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Gear / Technical Help => Post-Processing, Computer / Streaming / Internet Devices & Related Activity => Topic started by: justink on April 28, 2008, 10:59:25 PM

Title: Audacity (osx): How to mix two AUD sources?
Post by: justink on April 28, 2008, 10:59:25 PM
doing a SBD > R-09  and a 4023 > Aerco > R-09 tomorrow night.

what's the best way to mix these in post using Audacity... (or some other mac friendly and free application)?

thanks,

-j
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: morst on April 29, 2008, 04:54:13 AM
Let me give it a try for ya. These instructions should work fine on a mac or a PC running Audacity. Probably Linux too, though I have never tried it.

1- Run the masters so the levels peak below -3.0 dB on each if you can, so you can mix them without having to lower volume to avoid clipping peaks. Run them both at the same sample rate. Bit depth is not as important to match. Name each file descriptively including the type of source (Foobar2008-04-29-SBD-24bit.wav, Foobar2008-04-29-DPA-24bit.wav or some such)

2- Go to AUDACITY>PREFERENCES> QUALITY and set your default sample rate and bit depth to the desired settings (44100 with the desired output bit-depth). PROJECT>IMPORT both sources into audacity and FILE>SAVE your work.

3- Use the double-headed arrow "TIME SHIFT" tool in the top left corner (<-->) to line up the files as near as possible to the start of the music. Find a sharp peaking impulse like a drum hit or some other peak to line up and zoom in until they are as precisely aligned as possible.

4- If you think you need to do any EQ or level changes on either source, do this now. You can use EFFECT>AMPLIFY to tell you how high each source peaks. If each source peaks higher than -3.0dB at any point, you will get clipping on the mix, so you'll need to lower levels to avoid this. It is also possible to have one source higher than the other and still clip peaks. I am good but not great at math, so hopefully some other folks can chime in with suggestions and comments regarding levels. I think I have it right, that 2 signals of -3.0dB will add up to peak at -0.0dB so you want to stay below that.

5- Go to the end of the files and figure out how much they have drifted apart. Do some math* to figure out how much you need to use EFFECT>CHANGE SPEED to get them lined up (see below for my method of calculating the percent change)

6- I suggest shortening the longer file rather than stretching the shorter one, but it probably doesn't matter. Use the EFFECT>CHANGE SPEED to do that.

7- Check the alignment to make sure the sources stay together. If they are not correct, use EDIT> UNDO SPEED CHANGE and try step 6 again. When they are correct, FILE>SAVE your work again. As long as you keep the file open, you can UNDO past the file save operation, but once you close and open it again, you can't go back past the saved version.

8- Check the mix for sound by using the MUTE function on each track during playback to make sure it sounds good. Adjust the gain for each track if needed by using the +......- slider on the left of each track for course adjustment, or EFFECT>AMPLIFY for finer control.

9- Go to AUDACITY>PREFERENCES > QUALITY > HIGH-QUALITY DITHER and select "Triangle Dither"

10- FILE>EXPORT AS WAV (or AIFF) to make the mixed file. FILE>SAVE again. If you think you might need to make further adjustments after checking the completed file, keep this project session open so you can UNDO back. Name the file something descriptive like Foobar2008-04-29-MIX-24bit or Foobar2008-04-29-MATRIX-16bit so you can distinguish it from each source file.

11- FILE>OPEN a new Audacity project document and PROJECT>IMPORT the newly created mix file. EFFECT>AMPLIFY to check that all peaks are below -0.0dB. If this plugin does not offer to boost levels, then you probably have clipped a peak somewhere, and you will want to go back to the original files and lower the levels of one or both sources to preserve your dynamics and avoid flattening out peaks. If you have a little headroom and it sounds good, then you have successfully mixed your sources.

12- If you want to track for CD's, then VIEW>SET SELECTION FORMAT > CDDA min:sec:frames 75fps and then EDIT>SNAP TO> SNAP ON to allow you to cut tracks without "sector boundary errors." Select tracks in order by using EDIT> MOVE CURSOR TO TRACK START (I go into preferences and give it a keyboard shortcut to make this easier) then shift-clicking on the end of each track, then EDIT> SPLIT each track apart in order, making sure to split the final track too.

13- FILE> EXPORT MULTIPLE (NUMBERING CONSECUTIVELY) to WAV (or aiff) in your selected target directory.

14- Compress these files losslessly using your favorite FLAC encoder, and upload to your favorite sharing website, and post in the KICKDOWNS thread here so we can check it out.

15- please let me know if this is unclear or can be improved upon.  8)


* oh shoot, now I gotta figure out how to tell you the math part! My apologies for the half-assed nature of this part of my method.  :-[ Go to VIEW>SET SELECTION FORMAT > SAMPLES (SNAP TO SAMPLES) so you can measure the length of your program in samples. Measure the total length from your sync points early in the file to the desired sync points late in the file. You will get different numbers for each file since they are probably not lined up perfectly due to slight variances in the clock chips of the two recorders. Make a note of each of these numbers. Subtract one from the other to find out the number of samples of drift at the end, and write this number down. Divide the length of the longer one by the length of the shorter source and you will get a number close to but greater than 1.0000000. Let's use an example where you have exactly one second of drift at the end of exactly one hour at 48KHz. The longer file is now 172,848,000 samples and the shorter one is 172,800,000 samples. Divide the long one by the short one and you will get 1.0002788. (If I am getting this right, then) this tells you that you that you need to speed change the longer file by -.02788%

Damn I hope I got that right. Please won't someone troubleshoot my math and let me know the best way to do this???  :o
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: justink on April 29, 2008, 01:50:52 PM
thanks for typing all of this out!  i'll give it a shot.

i've been told by others to track the show out and line up each individual track, but this method sounds easier for some reason...

-j
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: morst on April 29, 2008, 02:10:45 PM
thanks for typing all of this out!  i'll give it a shot.

i've been told by others to track the show out and line up each individual track, but this method sounds easier for some reason...

-j
Glad it sounds easier. I wish it were simpler, but as Einstein said "Everything should be made as simple as possible, BUT NOT SIMPLER!!"

When you get the speed difference right, you only have to line it up once for each recording.  :)

edit- (Unless the speed of sound varies due to environmental factors such as temperature and humidity such that the sources become mis-aligned. . .)
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: ol' dirty taper on May 07, 2008, 04:04:22 PM
Morst


Thanks so much for typing this "How To" out for us here. I have been searching the archives for a couple days trying to find these exact steps! I have a couple shows lined up needing this post processing.

+T
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: willndmb on November 21, 2008, 01:27:36 PM
Let me give it a try for ya. These instructions should work fine on a mac or a PC running Audacity. Probably Linux too, though I have never tried it.

1- Run the masters so the levels peak below -3.0 dB on each if you can, so you can mix them without having to lower volume to avoid clipping peaks. Run them both at the same sample rate. Bit depth is not as important to match. Name each file descriptively including the type of source (Foobar2008-04-29-SBD-24bit.wav, Foobar2008-04-29-DPA-24bit.wav or some such)

2- Go to AUDACITY>PREFERENCES> QUALITY and set your default sample rate and bit depth to the desired settings (44100 with the desired output bit-depth). PROJECT>IMPORT both sources into audacity and FILE>SAVE your work.

3- Use the double-headed arrow "TIME SHIFT" tool in the top left corner (<-->) to line up the files as near as possible to the start of the music. Find a sharp peaking impulse like a drum hit or some other peak to line up and zoom in until they are as precisely aligned as possible.

4- If you think you need to do any EQ or level changes on either source, do this now. You can use EFFECT>AMPLIFY to tell you how high each source peaks. If each source peaks higher than -3.0dB at any point, you will get clipping on the mix, so you'll need to lower levels to avoid this. It is also possible to have one source higher than the other and still clip peaks. I am good but not great at math, so hopefully some other folks can chime in with suggestions and comments regarding levels. I think I have it right, that 2 signals of -3.0dB will add up to peak at -0.0dB so you want to stay below that.

5- Go to the end of the files and figure out how much they have drifted apart. Do some math* to figure out how much you need to use EFFECT>CHANGE SPEED to get them lined up (see below for my method of calculating the percent change)

6- I suggest shortening the longer file rather than stretching the shorter one, but it probably doesn't matter. Use the EFFECT>CHANGE SPEED to do that.

7- Check the alignment to make sure the sources stay together. If they are not correct, use EDIT> UNDO SPEED CHANGE and try step 6 again. When they are correct, FILE>SAVE your work again. As long as you keep the file open, you can UNDO past the file save operation, but once you close and open it again, you can't go back past the saved version.

8- Check the mix for sound by using the MUTE function on each track during playback to make sure it sounds good. Adjust the gain for each track if needed by using the +......- slider on the left of each track for course adjustment, or EFFECT>AMPLIFY for finer control.

9- Go to AUDACITY>PREFERENCES > QUALITY > HIGH-QUALITY DITHER and select "Triangle Dither"

10- FILE>EXPORT AS WAV (or AIFF) to make the mixed file. FILE>SAVE again. If you think you might need to make further adjustments after checking the completed file, keep this project session open so you can UNDO back. Name the file something descriptive like Foobar2008-04-29-MIX-24bit or Foobar2008-04-29-MATRIX-16bit so you can distinguish it from each source file.

11- FILE>OPEN a new Audacity project document and PROJECT>IMPORT the newly created mix file. EFFECT>AMPLIFY to check that all peaks are below -0.0dB. If this plugin does not offer to boost levels, then you probably have clipped a peak somewhere, and you will want to go back to the original files and lower the levels of one or both sources to preserve your dynamics and avoid flattening out peaks. If you have a little headroom and it sounds good, then you have successfully mixed your sources.

12- If you want to track for CD's, then VIEW>SET SELECTION FORMAT > CDDA min:sec:frames 75fps and then EDIT>SNAP TO> SNAP ON to allow you to cut tracks without "sector boundary errors." Select tracks in order by using EDIT> MOVE CURSOR TO TRACK START (I go into preferences and give it a keyboard shortcut to make this easier) then shift-clicking on the end of each track, then EDIT> SPLIT each track apart in order, making sure to split the final track too.

13- FILE> EXPORT MULTIPLE (NUMBERING CONSECUTIVELY) to WAV (or aiff) in your selected target directory.

14- Compress these files losslessly using your favorite FLAC encoder, and upload to your favorite sharing website, and post in the KICKDOWNS thread here so we can check it out.

15- please let me know if this is unclear or can be improved upon.  8)


* oh shoot, now I gotta figure out how to tell you the math part! My apologies for the half-assed nature of this part of my method.  :-[ Go to VIEW>SET SELECTION FORMAT > SAMPLES (SNAP TO SAMPLES) so you can measure the length of your program in samples. Measure the total length from your sync points early in the file to the desired sync points late in the file. You will get different numbers for each file since they are probably not lined up perfectly due to slight variances in the clock chips of the two recorders. Make a note of each of these numbers. Subtract one from the other to find out the number of samples of drift at the end, and write this number down. Divide the length of the longer one by the length of the shorter source and you will get a number close to but greater than 1.0000000. Let's use an example where you have exactly one second of drift at the end of exactly one hour at 48KHz. The longer file is now 172,848,000 samples and the shorter one is 172,800,000 samples. Divide the long one by the short one and you will get 1.0002788. (If I am getting this right, then) this tells you that you that you need to speed change the longer file by -.02788%

Damn I hope I got that right. Please won't someone troubleshoot my math and let me know the best way to do this???  :o
thanks
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: grtphl on January 09, 2009, 03:35:36 PM
Thanks!  Here's an obligatory thread bump for your great post.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: macacopowa on January 09, 2009, 04:21:59 PM
thanks a lot! an excellent "How To..." reference...+t for your good karma
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: groundhog2 on April 12, 2009, 03:45:22 PM
mucho thanks for your efforts morst.  this was very simple to read and apply.   sure is time consuming but worth the wait.  upping something right now ;D
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: georgeh on November 10, 2009, 12:13:19 PM
mucho thanks for your efforts morst.  this was very simple to read and apply.   sure is time consuming but worth the wait.  upping something right now ;D

bump for a thank you. still not sure if i can pull this off, but it wont be from lack of knowledge now :)
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: georgeh on November 10, 2009, 03:36:30 PM
I've spent most of today trying to do this with XP, crashes every time when i add time? About ready to give it up, but I do have some spare time to play with it more.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: acidjack on January 22, 2010, 08:03:57 AM
Just wanted to post a thank-you for this; extremely helpful.

One thing I didn't try, but am curious if others have, is if you can avoid the 4ch>2ch WAV>mix/track 2ch WAV>FLAC step and somehow track and amplify the 4ch WAV?  I assume it's tougher because it is hard to make your file peak at -0.1 and preserve the mix you want, but if anyone has tried this, I'd be curious to hear it.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: runonce on January 22, 2010, 08:24:22 AM
Just wanted to post a thank-you for this; extremely helpful.

One thing I didn't try, but am curious if others have, is if you can avoid the 4ch>2ch WAV>mix/track 2ch WAV>FLAC step and somehow track and amplify the 4ch WAV?  I assume it's tougher because it is hard to make your file peak at -0.1 and preserve the mix you want, but if anyone has tried this, I'd be curious to hear it.

Very often - you'll need that extra headroom. - When the sources combine, certain frequencies reinforce each other and produce peaks that will be louder than the individual sources peak. Keep an eye on the Audacity meters - playback peaky areas and watch for red in the meters. Red is bad.

Point is - the levels in the individual tracks dont reflect levels on the final export. Pumping up the individual levels to max before combining will almost guarantee a bunch of overs.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: page on January 22, 2010, 09:48:57 AM
Just wanted to post a thank-you for this; extremely helpful.

One thing I didn't try, but am curious if others have, is if you can avoid the 4ch>2ch WAV>mix/track 2ch WAV>FLAC step and somehow track and amplify the 4ch WAV?  I assume it's tougher because it is hard to make your file peak at -0.1 and preserve the mix you want, but if anyone has tried this, I'd be curious to hear it.

Very often - you'll need that extra headroom. - When the sources combine, certain frequencies reinforce each other and produce peaks that will be louder than the individual sources peak. Keep an eye on the Audacity meters - playback peaky areas and watch for red in the meters. Red is bad.

Point is - the levels in the individual tracks dont reflect levels on the final export. Pumping up the individual levels to max before combining will almost guarantee a bunch of overs.

Agreed, I find that I need up to 4-5db of headroom in the unmixed sources to prevent overages in the final rendering which usually lands within 1db. Often times, I'll actually drop 5 or 6db off of the raw sources, adjust wildly for a bit to see what I like as a tendancy, mix carefully in the realm where I found an inkling, and then write down the ratio of db between the two. Then I'll set my amp settings so I'll have the required headroom and the ratio and then render.

edit: forgot the second half of the question...

You can track in audacity at 4ch and thats preserved in the mixdown, and you can amplify just certain tracks in a 4ch wav file, but you have to associate the tracks seperately (if they come in as mono tracks then you are fine) or create stereo associations in audacity. Neither requires a render to wav, but it's a work-around. A rule of thumb is, if you have to use the mix/render or save as to Wav function more then once in the entire process in audacity, you either are using multiple programs in your workflow or you are doing an extra step somewhere.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: doodee on September 27, 2010, 11:02:06 PM
El referenco.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: auto_pilot on November 07, 2010, 03:24:50 PM
Just done my first matrix following your instructions. Very easy to follow, great results, confident that the effort required to make the two source recordings was worthwhile and shall be doing so again.

The time you took to write this out 2.5 years ago is very much appreciated.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: morst on November 11, 2010, 10:58:59 PM
Nice. Fachin' glad it's still useful!!

I will say that my workflow is a little different now. The main difference, is that the new audacity versions don't make you pick a sample rate before you start, so I do all my mixing at high-resolution now, then create the low-res (cd quality) version from that. The next change is that I decided I don't like Audacity's dither, so I turned it off.

My personal change is that I now use Digital Performer on the mac instead of audacity to do my work, but the old way is still reliable, and you can install all the software you need on any machine for free!! Damn handy on the road, or at mom's house!!
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: acidjack on December 10, 2010, 08:20:03 PM
I don't understand this, though.  The two files will be different in length anyway because they started at different times and stopped at different times. How do you account for that?  And if you select the link between two set points, it is always going to be the same, at least if you use the "label" function... Am I missing something?
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: capnhook on December 10, 2010, 11:58:02 PM
The only thing I'd add to morst's excellent instructions is that after saving the matrix, you can load it into the project you're working on.....check for overs and overall ratio.....and if you don't like what you see, dump the matrix from the project and tweak the sources for another try at it.

 That way, you don't lose any of your work, and you can iteratively improve the final matrix.    8)
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: auto_pilot on December 11, 2010, 02:41:03 AM
I don't understand this, though.  The two files will be different in length anyway because they started at different times and stopped at different times. How do you account for that?  And if you select the link between two set points, it is always going to be the same, at least if you use the "label" function... Am I missing something?

I've done three matrixes using this workflow now. All of them have a brief period at start and end where they're single-source after I've time-aligned. Most of this disappeared at the start of the show when I tracked the matrix, and at the end there's very little audience in the SBD source anyway so it's pretty much inaudible.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: danlynch on December 12, 2010, 03:39:38 PM
We're dealing with a small amount of drift between two different R-44's.  The drift ends up being about 110 milliseconds per hour.  The problem with "time stretch" in Soundforge is that this amount of stretching is too small.  Soundforge won't let me stretch anything below 100.01%, which is about 500 milliseconds. 
Any ideas?
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: auto_pilot on December 12, 2010, 06:04:20 PM
We're dealing with a small amount of drift between two different R-44's.  The drift ends up being about 110 milliseconds per hour.  The problem with "time stretch" in Soundforge is that this amount of stretching is too small.  Soundforge won't let me stretch anything below 100.01%, which is about 500 milliseconds. 
Any ideas?

The 'change speed' option in Audacity seems to have worked fine with 0.005% and 0.009% for the matrixes I've done so far
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: willndmb on March 30, 2011, 02:36:19 PM
:)
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: capnhook on May 25, 2011, 06:05:34 PM
We're dealing with a small amount of drift between two different R-44's.  The drift ends up being about 110 milliseconds per hour.  The problem with "time stretch" in Soundforge is that this amount of stretching is too small.  Soundforge won't let me stretch anything below 100.01%, which is about 500 milliseconds. 
Any ideas?

Divide the times into each other on a calculator,
change into a percentage difference,
copy the EXACT number from the calculator,
and paste it into Audacity's Speed Change.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: page on May 25, 2011, 06:21:41 PM
and paste it into Audacity's Speed Change.

I've never gotten the paste to work and have to type it manually. No biggie, but a minor pain.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: capnhook on June 19, 2011, 12:06:27 AM
and paste it into Audacity's Speed Change.

I've never gotten the paste to work and have to type it manually. No biggie, but a minor pain.

New software has a tendency to be more frustrating than what it replaces.... :P

You'll laugh.....I'm still on 1.2.6
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: ArchivalAudio on June 19, 2011, 04:14:01 AM
marking thread!
.
.
.
.
.
.
.
thanx!  ;D
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: achalsey on September 09, 2011, 01:37:08 AM
Bump for great thread going to page 2 and for probably a pointless question:

When adjusting the speed, are there any advantages/disadvantages to whether you lengthen the shorter track or shorten the longer track?  Normally I've found they're only fractions of a second off so I'm assuming it doesn't matter, but for whatever reason I seem to feel lengthening the shorter one would be better for some reason.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: page on September 09, 2011, 09:28:59 AM
Bump for great thread going to page 2 and for probably a pointless question:

When adjusting the speed, are there any advantages/disadvantages to whether you lengthen the shorter track or shorten the longer track?  Normally I've found they're only fractions of a second off so I'm assuming it doesn't matter, but for whatever reason I seem to feel lengthening the shorter one would be better for some reason.

I don't think it matters. A more pressing concern is to not stretch the source that will make the base of your mix. If you normalize both tracks to the same RMS level and then decide you want to use 70% of the sbd, then I'd stretch the room pull as each resample may induce further artifacts to the recording and I'd want the lesser used source to suffer compared to my base.

Whether that matters, I don't know, but it's no skin off my back to do it that way.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: gratefulphish on October 27, 2011, 01:16:50 PM
and paste it into Audacity's Speed Change.

I've never gotten the paste to work and have to type it manually. No biggie, but a minor pain.

I have not tried it in this particular setting, but many times when you cannot right click "copy" or "paste," you can do it by using the keyboard commands, "Control + "C" [copy] and "Control + "V" [paste].
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: NSL on November 14, 2011, 07:54:33 PM
I must be an idiot because I cannot figure this out and get it to work.  Can somebody go into more detail on the part about measuring the samples?  The numbers I get come out like the example in the description but when applying nothing changes at all.  Which numbers am I writing down and subtracting/dividing? 
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: achalsey on November 14, 2011, 08:52:14 PM
I'm not sure about the sample technique, but how I do it (and this may be a sloppier way I'm sure) is after I align the tracks at the beginning, zoom in as close as I can to two easily pinpointed notes that should be aligned as close to the end as possible and make a note of both.  Convert to seconds and divide the larger number by the smaller one and make the answer a % and put that into the change speed.

In other words, once you're aligned at the beginning, go as close to the end as possible to find two points that should be aligned.  Just like the beginning cymbal crashes or whatnot are easiest.  Zoom in all the way on the two exact points you think should be aligned and write down both times.  It should be HH:MM:SS:6 more digits.  Convert both times into seconds.  So if its over an hour set it would be something like 3700.399213 and 3701.223599.   Divide the larger number by the smaller one and turn the answer into a percentage to get how much you should change the longer file by.  Just like the sample method the answer should be something just over 1.

Also, either way, remember to highlight just from the point of alignment in the beginning not the whole file.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: NSL on November 14, 2011, 09:20:34 PM
Thanks for the reply, i'll give that a shot and see how it goes! 
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: NSL on November 20, 2011, 09:55:07 PM
Finally got around to and it sounds great!  Thanks for the help and for the guideline, much appreciated.   8)
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: justink on November 29, 2011, 03:47:30 AM
nevermind.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: bryonsos on December 17, 2011, 11:15:07 AM
12- If you want to track for CD's, then VIEW>SET SELECTION FORMAT > CDDA min:sec:frames 75fps and then EDIT>SNAP TO> SNAP ON to allow you to cut tracks without "sector boundary errors." Select tracks in order by using EDIT> MOVE CURSOR TO TRACK START (I go into preferences and give it a keyboard shortcut to make this easier) then shift-clicking on the end of each track, then EDIT> SPLIT each track apart in order, making sure to split the final track too.

Great resource, thanks again morst!

Is there any reason why you can't add labels for the tracks and "export multiple" as usual with a 2 track?

After you have things synced up, is it OK to cut excess crowd noise from the beginning and end of the file and do fades, or will those things create boundary errors etc?

Thanks in advance for any help/insight.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: justink on December 17, 2011, 12:09:24 PM
12- If you want to track for CD's, then VIEW>SET SELECTION FORMAT > CDDA min:sec:frames 75fps and then EDIT>SNAP TO> SNAP ON to allow you to cut tracks without "sector boundary errors." Select tracks in order by using EDIT> MOVE CURSOR TO TRACK START (I go into preferences and give it a keyboard shortcut to make this easier) then shift-clicking on the end of each track, then EDIT> SPLIT each track apart in order, making sure to split the final track too.

Great resource, thanks again morst!

Is there any reason why you can't add labels for the tracks and "export multiple" as usual with a 2 track?

After you have things synced up, is it OK to cut excess crowd noise from the beginning and end of the file and do fades, or will those things create boundary errors etc?

Thanks in advance for any help/insight.

once lined up, get the mix you want (more or less of one over the other source), then mix/render.  after that, you're free to do whatever other things you want.  i always use custom labels and export multiple.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: Hypnocracy on December 17, 2011, 02:09:55 PM
When adjusting time...How close is close enough? I have yet to get it exact but with in .02 seconds is about as close as I have come...

Talk to me about this not doing the whole file and just the selected to end?

Also, either way, remember to highlight just from the point of alignment in the beginning not the whole file.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: achalsey on December 17, 2011, 02:56:42 PM

Talk to me about this not doing the whole file and just the selected to end?

Also, either way, remember to highlight just from the point of alignment in the beginning not the whole file.

I just realized I haven't been doing it as accurately as possible.  I haven't been removing the time prior to the point of alignment from the equation.

What should be measured is the total samples (or seconds as I do it) just from the beginning point of alignment to where they should meet up in the end.  Since the percentage difference you get at the end is just the percent you need to change for that specific area, if you changed the speed of more than just that area, it would end up off.  (I'm not good at this, someone else can probably explain it better if that doesn't make sense)

In other words I guess;  If your original point of alignment for both tracks is at :10 (seconds) and the point of alignment you want at the end is say 1:00 (minute) and on the second track that same point is at 1:01.  Your calculations should only be measured from :10 (beginning alignment) to 1:00 and 1:01 (points you want to align at the end), since technically before and after those two points will be off after this.  Divide the larger number (sample) by the smaller whatever to find the percentage difference of just the area from the original alignment (:10) to 1:00.  That means if you changed the speed of anything more (or less) than that specific area (ie highlight the whole file), the percent speed change would be different and therefore the tracks would be slightly off.

Does that make sense?
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: bryonsos on December 17, 2011, 03:08:33 PM
12- If you want to track for CD's, then VIEW>SET SELECTION FORMAT > CDDA min:sec:frames 75fps and then EDIT>SNAP TO> SNAP ON to allow you to cut tracks without "sector boundary errors." Select tracks in order by using EDIT> MOVE CURSOR TO TRACK START (I go into preferences and give it a keyboard shortcut to make this easier) then shift-clicking on the end of each track, then EDIT> SPLIT each track apart in order, making sure to split the final track too.

Great resource, thanks again morst!

Is there any reason why you can't add labels for the tracks and "export multiple" as usual with a 2 track?

After you have things synced up, is it OK to cut excess crowd noise from the beginning and end of the file and do fades, or will those things create boundary errors etc?

Thanks in advance for any help/insight.

once lined up, get the mix you want (more or less of one over the other source), then mix/render.  after that, you're free to do whatever other things you want.  i always use custom labels and export multiple.

Thanks! Exactly what I needed to know.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: Hypnocracy on December 17, 2011, 10:15:12 PM
Ok...I have been calculating the time shift for a portion of the recording...so If I know the ratio I just need to apply that ratio to the whole in order to get it (closer) to exact

Measured segments

1:00:03/1:00:00

Total Recording is x/1:10:00

Solve for x equals the new time to shift the whole to...if the time was in 100ths of a hour instead of multiples of 60...now I see why they use samples instead of time...

Starting to become clear as mud....
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: morst on December 19, 2011, 11:19:37 PM
Great resource, thanks again morst!
Is there any reason why you can't add labels for the tracks and "export multiple" as usual with a 2 track?
No reason, but in 2008, I didn't know to do it the easy way!

...now I see why they use samples instead of time...

Starting to become clear as mud....
Yeah, do the stretch move based on the file lengths measured in samples, you get one nice exact number for each file. In the new 1.3.14 version, and the past few betas, you can set "time mode" to "sample" at the bottom of the screen for start, length, and position.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: cunger on December 22, 2011, 10:09:10 PM
I have a slightly off topic question. I have two audio sources for the same show. Instead of performing a matrix, I'd like to use Audacity to track both recordings at the same time. I believe I can take the instructions from the original post to do this? Here's what I'm thinking:
Import both recordings into Audacity, align the beginning.
Label the tracks.
Save the project.
Delete the first track.
Export multiple.
Reopen the project, delete the second track, export multiple.

Does anyone have an easier way to handle this? I tried to mute the unwanted source, but it still includes it in the export.

Thanks.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: justink on December 23, 2011, 06:23:03 AM
I have a slightly off topic question. I have two audio sources for the same show. Instead of performing a matrix, I'd like to use Audacity to track both recordings at the same time. I believe I can take the instructions from the original post to do this? Here's what I'm thinking:
Import both recordings into Audacity, align the beginning.
Label the tracks.
Save the project.
Delete the first track.
Export multiple.
Reopen the project, delete the second track, export multiple.

Does anyone have an easier way to handle this? I tried to mute the unwanted source, but it still includes it in the export.

Thanks.

sounds good to me.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: Walstib62 on December 23, 2011, 11:35:21 AM
Note: It helps a LOT if you do this first:
1. Import tracks
2. Align the tracks as close to the beginning as possible by shifting one L or R.
3. Now, make a single cut to all tracks at the beginning so that the track starts are the same, and the beginning is lined up. This makes all the later steps a lot easier.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: runonce on December 24, 2011, 09:19:43 AM
I have a slightly off topic question. I have two audio sources for the same show. Instead of performing a matrix, I'd like to use Audacity to track both recordings at the same time. I believe I can take the instructions from the original post to do this? Here's what I'm thinking:
Import both recordings into Audacity, align the beginning.
Label the tracks.
Save the project.
Delete the first track.
Export multiple.
Reopen the project, delete the second track, export multiple.

Does anyone have an easier way to handle this? I tried to mute the unwanted source, but it still includes it in the export.

Thanks.

I see - you're basically trying to track 2 shows at once.
Open 1 show and track it...Export Multiple - ok that show is done.
Next close that tracks you just worked with - but leave the marker track.
Open the next show - use the time align tool to make sure the markers still match the music.
Export multiple again.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: morst on December 26, 2011, 06:50:34 AM
I have a slightly off topic question.(snip)
Export multiple.
Reopen the project, delete the second track, export multiple.

Does anyone have an easier way to handle this?
Thanks.
The UNDO feature is your friend. But essentially, you have found an easy way to do it.

I would probably track with one muted, and right before the "export multiple" simply delete one track. Then after the export, UNDO the delete, and trash the one you just successfully exported. Export the other version, Undo the second delete, and save the file for later in case you screwed up.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: cunger on December 27, 2011, 09:43:56 AM
^^^ That's what I was thinking, just thought there might have been a better way. Thanks all!
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: ovtaper on January 03, 2012, 04:26:22 PM
i have a couple of off topic audacity questions that might possibly get answered amongst you all....
1. i have  a recording where the levels from one side to the other drop out completely. is there a way to take levels from one side to the other?
2 i have a recording that appears to have a low squeal most likely from connections in line in front of me. is there a way to eliminate this from the recording?

thanks + happy new year!!
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: GNRrockslife on January 20, 2012, 11:38:05 PM

* oh shoot, now I gotta figure out how to tell you the math part! My apologies for the half-assed nature of this part of my method.  :-[ Go to VIEW>SET SELECTION FORMAT > SAMPLES (SNAP TO SAMPLES) so you can measure the length of your program in samples. Measure the total length from your sync points early in the file to the desired sync points late in the file. You will get different numbers for each file since they are probably not lined up perfectly due to slight variances in the clock chips of the two recorders. Make a note of each of these numbers. Subtract one from the other to find out the number of samples of drift at the end, and write this number down. Divide the length of the longer one by the length of the shorter source and you will get a number close to but greater than 1.0000000. Let's use an example where you have exactly one second of drift at the end of exactly one hour at 48KHz. The longer file is now 172,848,000 samples and the shorter one is 172,800,000 samples. Divide the long one by the short one and you will get 1.0002788. (If I am getting this right, then) this tells you that you that you need to speed change the longer file by -.02788%

Damn I hope I got that right. Please won't someone troubleshoot my math and let me know the best way to do this???  :o

I'm sure this is a stupid question, but has this process changed in more recent versions of Audacity over the past 4 years? I can't seem to find "set selection format" under "View" in my current version of Audacity. I'm running version 1.3.14 for Mac. Again, sorry for a stupid question.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: page on January 21, 2012, 02:33:04 AM

* oh shoot, now I gotta figure out how to tell you the math part! My apologies for the half-assed nature of this part of my method.  :-[ Go to VIEW>SET SELECTION FORMAT > SAMPLES (SNAP TO SAMPLES) so you can measure the length of your program in samples. Measure the total length from your sync points early in the file to the desired sync points late in the file. You will get different numbers for each file since they are probably not lined up perfectly due to slight variances in the clock chips of the two recorders. Make a note of each of these numbers. Subtract one from the other to find out the number of samples of drift at the end, and write this number down. Divide the length of the longer one by the length of the shorter source and you will get a number close to but greater than 1.0000000. Let's use an example where you have exactly one second of drift at the end of exactly one hour at 48KHz. The longer file is now 172,848,000 samples and the shorter one is 172,800,000 samples. Divide the long one by the short one and you will get 1.0002788. (If I am getting this right, then) this tells you that you that you need to speed change the longer file by -.02788%

Damn I hope I got that right. Please won't someone troubleshoot my math and let me know the best way to do this???  :o

I'm sure this is a stupid question, but has this process changed in more recent versions of Audacity over the past 4 years? I can't seem to find "set selection format" under "View" in my current version of Audacity. I'm running version 1.3.14 for Mac. Again, sorry for a stupid question.

no worries

on the bottom left there are a couple of things. (left to right)

1) Project rate
2) Snap to Grid
3) Selection counter

on the right side of the selection counter is a little black triangle, click that once and then a menu comes up for what you what the display as. Set that to Samples.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: GNRrockslife on January 21, 2012, 02:51:01 PM

* oh shoot, now I gotta figure out how to tell you the math part! My apologies for the half-assed nature of this part of my method.  :-[ Go to VIEW>SET SELECTION FORMAT > SAMPLES (SNAP TO SAMPLES) so you can measure the length of your program in samples. Measure the total length from your sync points early in the file to the desired sync points late in the file. You will get different numbers for each file since they are probably not lined up perfectly due to slight variances in the clock chips of the two recorders. Make a note of each of these numbers. Subtract one from the other to find out the number of samples of drift at the end, and write this number down. Divide the length of the longer one by the length of the shorter source and you will get a number close to but greater than 1.0000000. Let's use an example where you have exactly one second of drift at the end of exactly one hour at 48KHz. The longer file is now 172,848,000 samples and the shorter one is 172,800,000 samples. Divide the long one by the short one and you will get 1.0002788. (If I am getting this right, then) this tells you that you that you need to speed change the longer file by -.02788%

Damn I hope I got that right. Please won't someone troubleshoot my math and let me know the best way to do this???  :o

I'm sure this is a stupid question, but has this process changed in more recent versions of Audacity over the past 4 years? I can't seem to find "set selection format" under "View" in my current version of Audacity. I'm running version 1.3.14 for Mac. Again, sorry for a stupid question.

no worries

on the bottom left there are a couple of things. (left to right)

1) Project rate
2) Snap to Grid
3) Selection counter

on the right side of the selection counter is a little black triangle, click that once and then a menu comes up for what you what the display as. Set that to Samples.
Thanks, that helped me get the sample numbers I need, but it seems to fall out of sync even worse I apply the "change speed". Could someone verify that I'm doing this process correctly? Sorry to be such a pain in the ass, this is my first time attempting a matrix. Here's my numbers:
- Longer recording is 292,879,639 samples (From the first sample to the sample that the last beat of music occurs on, with both sources synced up at the beginning)
- Shorter recording is 290,252,451 samples (Under the same circumstances)
- The quotient is 1.0090514
- The percentage change in speed for the longer recording should be -.90514% (Audacity rounds to -.905%)

Am I doing something wrong in this process?
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: page on January 22, 2012, 12:37:30 AM
Thanks, that helped me get the sample numbers I need, but it seems to fall out of sync even worse I apply the "change speed". Could someone verify that I'm doing this process correctly? Sorry to be such a pain in the ass, this is my first time attempting a matrix. Here's my numbers:
- Longer recording is 292,879,639 samples (From the first sample to the sample that the last beat of music occurs on, with both sources synced up at the beginning)
- Shorter recording is 290,252,451 samples (Under the same circumstances)
- The quotient is 1.0090514
- The percentage change in speed for the longer recording should be -.90514% (Audacity rounds to -.905%)

Am I doing something wrong in this process?

If it goes from being out of sync by 3 seconds at the end to being out of sync by 6, then you went the wrong way (duh, but stating it to build upon). What you're telling it is to expand a track. If you did 0.905xxxxx (and type all of that stuff in, don't cheap out) then it should shrink the track selected. A change of 1.00000 does nothing, that's your base line, not 0.

I used to squirrel around for a good 15 minutes trying to remember how to do this every time as I rarely got it on the first try.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: morst on January 22, 2012, 04:24:08 PM
The original directions I wrote were for version 1.2.6 I think. Version 1.3x is much better, as you can change sample rates whenever you like, for export.

If the (+ or -) sign is wrong, you can either reverse it, or do the process on the other of the two tracks. (shrink one or stretch the other)
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: justink on February 03, 2012, 06:23:23 PM
the newest version of Audacity seems to have a sync option (sync/lock tracks - the little clock at the top).  has anyone tried using this/know how it works?
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: runonce on February 04, 2012, 09:57:45 AM
the newest version of Audacity seems to have a sync option (sync/lock tracks - the little clock at the top).  has anyone tried using this/know how it works?

I think...it keeps the tracks in sync if you happen to edit one trackset. (perhaps some processes can cause a lapse in sync?)

I know you need to turn it off before you import your second trackset - otherwise, it will start at the end of the first trackset.

Once you have your tracks imported - click it back on...

I dont think it has anything to do with fixing clock drift...
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: Chimney Top on October 17, 2012, 01:34:57 AM
Final Cut Pro X has a sync clips function for video and/or audio tracks... it's instant, but still not 100%... if you sync individual tracks it's probably ok... clips 60 minutes plus... not so much, but decent (then you can drag/zoom to align).  FCPX only exports at 48 khZ, but you might able to send to compressor then export at other sample rates.

FCPX also has a 31 band eq, panning, surround panning, etc.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: chinariderstl on February 10, 2013, 03:48:27 PM
Marking thread.  :)
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: intpseeker on August 27, 2016, 03:20:13 PM
Using my DR70-d, I took the 2 channels of soundboard and 2 channels of split omnis (outside gig), exported each separately as 16/44 stereo files. Then opened one in audacity and pasted the other into that project, I used mix and render and got a very nice matrix.

My question: can I create a matrix using 60 or 70% of the soundboard. (I'm assuming my first effort was a 50/50 mix.

Thanks!
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: achalsey on August 27, 2016, 11:02:39 PM
Definitely.  Though your first mix was most likely not "50/50."

The levels were probably somewhat different for each source and just loading them into Audacity and combining into one stereo track won't give you an even mix.

But to your question: at the very basic level, when you open files in audacity there is a gain slider for each file on the left side of the screen.  Its the one that just has the '+' and '-' symbols on both ends.  Above the 'L' and 'R' slider.

When listening to the show in Audacity just play with turning one source up or down and see how it sounds and what you like best.  Make sure the animated green bars in the top tool bar never show red.

ALL THAT SAID, have you been following the rules outlined in the beginning of this thread to align both sources?  The soundboard source and the omnis will almost certainly not be totally in sync and could cause an echo effect by the end of the set.  Thats a whole other can of worms that needs to be opened before you can get the right sound mix done.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: intpseeker on August 28, 2016, 02:14:01 PM
Definitely.  Though your first mix was most likely not "50/50."

The levels were probably somewhat different for each source and just loading them into Audacity and combining into one stereo track won't give you an even mix.

But to your question: at the very basic level, when you open files in audacity there is a gain slider for each file on the left side of the screen.  Its the one that just has the '+' and '-' symbols on both ends.  Above the 'L' and 'R' slider.

When listening to the show in Audacity just play with turning one source up or down and see how it sounds and what you like best.  Make sure the animated green bars in the top tool bar never show red.

ALL THAT SAID, have you been following the rules outlined in the beginning of this thread to align both sources?  The soundboard source and the omnis will almost certainly not be totally in sync and could cause an echo effect by the end of the set.  Thats a whole other can of worms that needs to be opened before you can get the right sound mix done.

I wasn't aware of/considering alignment at all, but when I began reading here, phasing came up and I checked the first kick drum spike and the two tracks were dead on. I just checked the last song,
and the spikes were still dead on. The soundboard and I were maybe 80-90 feet from the stage lip.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: Life In Rewind on August 28, 2016, 02:23:07 PM
Definitely.  Though your first mix was most likely not "50/50."

The levels were probably somewhat different for each source and just loading them into Audacity and combining into one stereo track won't give you an even mix.

But to your question: at the very basic level, when you open files in audacity there is a gain slider for each file on the left side of the screen.  Its the one that just has the '+' and '-' symbols on both ends.  Above the 'L' and 'R' slider.

When listening to the show in Audacity just play with turning one source up or down and see how it sounds and what you like best.  Make sure the animated green bars in the top tool bar never show red.

ALL THAT SAID, have you been following the rules outlined in the beginning of this thread to align both sources?  The soundboard source and the omnis will almost certainly not be totally in sync and could cause an echo effect by the end of the set.  Thats a whole other can of worms that needs to be opened before you can get the right sound mix done.

I wasn't aware of/considering alignment at all, but when I began reading here, phasing came up and I checked the first kick drum spike and the two tracks were dead on. I just checked the last song,
and the spikes were still dead on. The soundboard and I were maybe 80-90 feet from the stage lip.

You wont have drift - your 4 tracks are clock synced from the same recorder - drift is only an issue when you mix sources from different recorders.

Not sure how you got away without having delay issues - at 80 feet it should be VERY noticeable...be sure to zoom in a lot when checking...

Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: voltronic on August 28, 2016, 05:24:07 PM
Definitely.  Though your first mix was most likely not "50/50."

The levels were probably somewhat different for each source and just loading them into Audacity and combining into one stereo track won't give you an even mix.

But to your question: at the very basic level, when you open files in audacity there is a gain slider for each file on the left side of the screen.  Its the one that just has the '+' and '-' symbols on both ends.  Above the 'L' and 'R' slider.

When listening to the show in Audacity just play with turning one source up or down and see how it sounds and what you like best.  Make sure the animated green bars in the top tool bar never show red.

ALL THAT SAID, have you been following the rules outlined in the beginning of this thread to align both sources?  The soundboard source and the omnis will almost certainly not be totally in sync and could cause an echo effect by the end of the set.  Thats a whole other can of worms that needs to be opened before you can get the right sound mix done.

I wasn't aware of/considering alignment at all, but when I began reading here, phasing came up and I checked the first kick drum spike and the two tracks were dead on. I just checked the last song,
and the spikes were still dead on. The soundboard and I were maybe 80-90 feet from the stage lip.

You wont have drift - your 4 tracks are clock synced from the same recorder - drift is only an issue when you mix sources from different recorders.

Not sure how you got away without having delay issues - at 80 feet it should be VERY noticeable...be sure to zoom in a lot when checking...

Another way to check this is to put on headphones, pan one source hard left and the other hard right.  When they don't line up you'll start getting dizzy!  That's also a method I sometimes use to balance two tracks by ear.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: achalsey on August 28, 2016, 10:52:14 PM
Oooh, right.  My mistake.  Not drift by the end, but the two sources won't be aligned at the beginning.

The SBD feed should show up at your recorder basically immediately (electricity theoretically travels at the speed of light) while the mic source has to wait for the sound to travel through the air.  At 80-90' from the PA there definitely should be a discrepancy between the start of the SBD source and the mic source.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: danlynch on August 29, 2016, 12:15:39 AM
General rule is one millisecond per foot between the sources, i.e. mics 50 feet from the stage needs a shift of 50 milliseconds between AUD (slower) and SBD (faster) sources.  But the number can be adjusted by other factors, mainly the introduction of delay into the system by the FOH.  Its best to check the among various points in each source (usually using drum clicks) to check for the correct shift amount.



Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: morst on August 29, 2016, 05:09:22 PM
and the spikes were still dead on. The soundboard and I were maybe 80-90 feet from the stage lip.
Were the mics on the stage lip? That would explain the lack of much difference between the SBD feed which is also made of mics on stage...

otherwise, 80 feet is about 71 ms according to my favorite relevant widget:
mac kids, check this out: https://www.apple.com/downloads/dashboard/calculate_convert/soundreference.html
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: intpseeker on August 29, 2016, 10:08:40 PM
and the spikes were still dead on. The soundboard and I were maybe 80-90 feet from the stage lip.
Were the mics on the stage lip? That would explain the lack of much difference between the SBD feed which is also made of mics on stage...

otherwise, 80 feet is about 71 ms according to my favorite relevant widget:
mac kids, check this out: https://www.apple.com/downloads/dashboard/calculate_convert/soundreference.html

The mics were a bout 2 feet from the soundboard, 10 feet in the air.

I have cherry-picked spikes throughout the 2 hour gig, including a spike very near  the end of the last song, and zoomed in, the two tracks are dead on. I thought that maybe
I somehow took two soundboards or two audience pulls when  combined them, but when separated, one is dry and one has applause and chatter.

It could be that I'm not hearing the echo, but the last song sounds pretty good.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: Life In Rewind on August 30, 2016, 08:03:32 AM
and the spikes were still dead on. The soundboard and I were maybe 80-90 feet from the stage lip.
Were the mics on the stage lip? That would explain the lack of much difference between the SBD feed which is also made of mics on stage...

otherwise, 80 feet is about 71 ms according to my favorite relevant widget:
mac kids, check this out: https://www.apple.com/downloads/dashboard/calculate_convert/soundreference.html

The mics were a bout 2 feet from the soundboard, 10 feet in the air.

I have cherry-picked spikes throughout the 2 hour gig, including a spike very near  the end of the last song, and zoomed in, the two tracks are dead on. I thought that maybe
I somehow took two soundboards or two audience pulls when  combined them, but when separated, one is dry and one has applause and chatter.

It could be that I'm not hearing the echo, but the last song sounds pretty good.

Your distance from the soundboard is not very important...its all about the distance from the soundmakers and the mics.

The only thing that could account for this is - the soundman knew what you were doing and added the appropriate delay to your feed...Id say that is unlikely.

Similarly - if there were a set of delay stacks - and they were relatively even with the board - and you got that signal?

The other thing I thought of - you accidentally used the internal mics? Doesn't sound like it - but it would account for the lack of delay.

You can add this delay with the 70D - but you would have known if you did...not something you can set accidentally
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: morst on August 30, 2016, 02:53:52 PM
You can add this delay with the 70D - but you would have known if you did...not something you can set accidentally
Unless you set it a while ago, and forgot about it?!
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: intpseeker on September 01, 2016, 05:40:52 PM
and the spikes were still dead on. The soundboard and I were maybe 80-90 feet from the stage lip.
Were the mics on the stage lip? That would explain the lack of much difference between the SBD feed which is also made of mics on stage...

otherwise, 80 feet is about 71 ms according to my favorite relevant widget:
mac kids, check this out: https://www.apple.com/downloads/dashboard/calculate_convert/soundreference.html

The mics were a bout 2 feet from the soundboard, 10 feet in the air.

I have cherry-picked spikes throughout the 2 hour gig, including a spike very near  the end of the last song, and zoomed in, the two tracks are dead on. I thought that maybe
I somehow took two soundboards or two audience pulls when  combined them, but when separated, one is dry and one has applause and chatter.

It could be that I'm not hearing the echo, but the last song sounds pretty good.

Your distance from the soundboard is not very important...its all about the distance from the soundmakers and the mics.

The only thing that could account for this is - the soundman knew what you were doing and added the appropriate delay to your feed...Id say that is unlikely.

Similarly - if there were a set of delay stacks - and they were relatively even with the board - and you got that signal?

The other thing I thought of - you accidentally used the internal mics? Doesn't sound like it - but it would account for the lack of delay.

You can add this delay with the 70D - but you would have known if you did...not something you can set accidentally

I've worked with the sound guy, and when I asked if I could plug in, he was running to the stage and yelled back to use the rca outs, which I did. So he didn't have a lot to do with it.

I went through (all) the menus for the mics and it doesn't seem that I used the internals, mic+phantom was picked, plus the internals buried in the bottom of my bag, etc.

A question: If I had used the internals, why wouldn't I still have the lag from 80 feet away?
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: Life In Rewind on September 02, 2016, 09:50:34 AM

A question: If I had used the internals, why wouldn't I still have the lag from 80 feet away?

The speculation was: you ran your mics on your stand (1/2) - and had accidentally run the internal mics.(3/4)  Those two sets of mics would be physically very close to each other - and wouldn't have any lag.

But - doesnt sound like thats what happened...

At this point - its a mystery!

Post a sample if you can - see if anyone hears anything...
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: intpseeker on September 05, 2016, 02:34:13 PM

A question: If I had used the internals, why wouldn't I still have the lag from 80 feet away?

The speculation was: you ran your mics on your stand (1/2) - and had accidentally run the internal mics.(3/4)  Those two sets of mics would be physically very close to each other - and wouldn't have any lag.

But - doesnt sound like thats what happened...

At this point - its a mystery!

Post a sample if you can - see if anyone hears anything...


Well...that's a 'duh' moment on my part.

As it turns out the singer in the band noticed a bit of 'digital delay' on two of her songs in the middle of the gig. Wanna bet it was about 75 milliseconds worth?

Sounds like a touch of reverb.

I'm back to the drawing board figuring out how to align the tracks.

Thanks to all for the info. This has been a fun learning experience for me.

Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: morst on September 09, 2016, 05:42:41 PM
Well...that's a 'duh' moment on my part.

As it turns out the singer in the band noticed a bit of 'digital delay' on two of her songs in the middle of the gig. Wanna bet it was about 75 milliseconds worth?

Sounds like a touch of reverb.
HAHA! Awesome, ya found the problem, now you can solve it!

Go to the tracks with the delay, and use the original peak, not the delayed peak. Typically, short delay (less than 100 ms or so) is used as a thickening, or doubling effect and the peaks of the delayed signal might be nearly as high, or just as high as the original source signal (her voice.)

Longer delays are often used as an echo effect, and those are usually not mixed as loud as the original signal. Longer delay sometimes has multiple "returns" of the signal, typically at a decreasing level, to mimic a natural echo. If your echo came back louder than your voice in nature, it would sound weird, so too in music. But at very fast rates like you might have, returning just as loud is actually an option.

Heads up from the sound mixing dept...  :cheers:
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: Gutbucket on September 13, 2016, 05:11:49 PM
I'll recap for folks following along who may be scratching their heads a bit.

When mixing multiple sources, the final resulting "combined" recording will benefit most when:
1) All sources to be mixed have been checked for time synchronization and correctly synchronized with each other if required.
2) Appropriate adjustments are made to each source individually, before the sources are mixed together.
3) The sources are mixed using the most appropriate level relationship, which may be constant throughout the recording or varied over time.
4) Appropriate adjustments are made to the resulting combined file.

I'll follow up with some comments on each of these points..
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: Gutbucket on September 13, 2016, 07:13:37 PM
On point 1)-

Time synchronization issues manifest in two ways:

A) Time-offset difference-  a difference in time-alignment of the same events as represented across multiple the sources.  On playback, the time-offset will remain constant throughout the recording, unless there also happened to be a clock-rate difference between recorders (and unless the source or microphones are moved while recording).   If recorded using a single multichannel recorder or multiple devices which share the same clock data, the time-offset at that at the end of the recording will be exactly the same as the time offset at the beginning of the recording.  There is offset, but no "drift".

B) Clock-rate differencee- a difference between the nominal sampling rate at which the recordings were made, and the actual clock rates at which the two sources were sampled, when recording the same events to separate recorders that do not share the same clock-data.  For example- two recorders writing 48kHz audio files will sample the analog audio signals very close to, but quite exactly 48,000 times per second.  In actuality, the clock of one recorder is going to run ever so slightly slower than the other.  Like a time-offset, such a clock-rate difference should remain constant throughout the recording as well (hopefully! If not it would be far more challenging to correct*).  On playback, that slight difference between recording clocks manifests as a cumulative "additive" time difference when both sources are reconstructed to their nominal 48kHz rate using a single playback clock.  If the two sources are time-aligned at the start, and then played back using single playback clock, the slight difference between their actual recording sample rates will cause them to slowly "drift" out of synchronization as the file plays.  The longer the recording, the more out of sync the two sources "drift" by the end.

It's frequently the case that only a time-offset exists and needs correction. When sample-rate difference also exists, there is going to be a time offset as well.


For concert tapers, a time offset between sources is most commonly caused by the difference in the speed of sound through air verses an electrical signal through a wire.  Mics placed out in the audience further away pick up a sound significantly later than mics on-stage.  But there are other sources of time-offset too. Even when recording simultaneously to several recorders which are "clock-linked" so as to operate using the same sample clock, the different recordings may not start and stop at exactly the same time.  A recordist may need to push record and stop separately on each machine.  The resulting sources will have been sampled at exactly the same clock-rate, but they will need to be time-aligned later.  Time-offset is corrected for by offsetting one source in time with respect to the other.  That can be achieved by starting playback of each at exactly the right time, with a delay line, or most commonly and most easily by shifting one source along the playback time-line with respect to the other in the audio editing program.  By ear, it's is most easily done by listening to segments containing sparse speech (stage announcements and banter) or sparse sharp transients sounds like a single clap, snare or drum hit, or the like.  Zooming in on the waveforms, one may be able to see and align the peak of the transient.  Either way, it's easiest when the event being used stands out clearly from the background sounds, and difficult to impossible during dense passages.  Although there are exceptions, ordinarily the goal is to shift one source in time with respect to the other until a transient representing the same event occurs simultaneously, sounding clear and concise with no echo or blur.

A sample-rate difference occurs when recording to two or more separate, non-clock-linked recorders.  In that case, each recorder digitally samples the signals it is converting based on it's own local clock.  The clock-rate difference between clocks may be pretty close or not be particularly close, but in either case, if the recording runs long enough there will be some measurable difference between them, in addition to the time-offset difference between the starting and stopping points of the recordings.  This "drift" is sometimes so minimal it doesn't require correction.  Other times it causes a significantly audible effect which grows more severe until it becomes a blur and eventually an obviously discernible echo.    There are multiple ways of correcting for this.  One older, less than optimal method was to divide both sources into single song files, then individually align each song at it's beginning. The hope being that the time-offset "drift" is not significant enough to become audible before each song ends and the next begins.  The more appropriate and modern way of addressing the problem requires modifying the time-basis of one of the sources with respect to the other.  In effect, the length of one source is either "stretched" or "shrunk" to match that of the other.  In some software that's done via entering a new time-length for the file, after doing some work with a calculator to figure out the correct value. In others it's via entering a percentage or +/- value into a stretch/shrink function, by dragging the duration envelope of one source, or by manipulating a parameter value for the the source object.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: Gutbucket on September 13, 2016, 08:16:15 PM
*Footnote to my post above-

The clock-rate difference "drift factor" is pretty much constant in that each clock may exhibit significant difference over time in comparison with another clock, yet will still be very consistent with itself unless something is very wrong.  Here's one interesting example of that- Say one records two sources using two separate non-clock-linked recorders only to find there is significant drift between sources when transferred to a computer for playback.  If one instead plays back the resulting files on the same non-clock-linked recorders which originally recorded the files, the sources will effectively retain synchronization for the the entire recording without otherwise having to correct for the drift.  That's because each recorder then operates as it's own complete self-contained sample and reconstruction device, both sampling  and reconstructing using it's own clock, which remains consistent with itself.  Each recorder is it's own analog>digital>analog world in isolation, and effectively cancels out its own clock rate error, as long as that error remains constant. 

The trick in actually doing that is accommodating for the inevitable time-offset between sources at the start of playback.  I used to do this before I owned multichannel recorders, using two original Edirol R-09s , accommodating time-offset by using a series of rapid jabs to the play/pause/play button of whichever machine was slightly ahead of the other.  It helped greatly if the two sources were playing back through separate speakers and I could place my head midway between them to carefully and listen for full elimination of delay and phase effects while jabbing.  It took concentration and looked pretty funny, but it worked for multichannel playback, and helped me develop the ability to identify very slight degrees of misalignment by ear.  I also tried it a few times with three separate recordings, which was incredibly difficult!

Non-constant drifting of the clock rate can of course happen as well, it's just usually more subtle.  At the level of digital samples that manifests as "jitter" distortion.  At an order of magnitude larger time-scale, analogous time fluctuations manifest as tape-speed "flutter" distortion, and at a still larger timescale the "wow" distortion of a record-player turntable.  All these are "clock" speed-rate distortions of various types in different mediums.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: morst on September 25, 2016, 04:15:55 PM
Excellent points, well-summarized!

That's because each recorder then operates as it's own complete self-contained sample and reconstruction device, both sampling  and reconstructing using it's own clock, which remains consistent with itself.  Each recorder is it's own analog>digital>analog world in isolation, and effectively cancels out its own clock rate error, as long as that error remains constant. 
We hope this is true. If you record a show outdoors in winter but transcribe with decks at room temperature, you might find that there is more variation than you expect!?

Also, back in the old days of Chop-And-Paste, one fudge factor was to align individual songs or sections in their middles rather than their starts. This effectively cut the drift in half at the in and out points of each section, in comparison to letting it drift "all the way out" before resynching.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: justink on October 04, 2016, 12:54:56 PM
i just can not figure this out... i feel like i'm doing all the math correctly but it's just not syncing.  i think it has to do with audacity only lets you go a few digits on the % change.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: capnhook on October 04, 2016, 03:49:41 PM
i just can not figure this out... i feel like i'm doing all the math correctly but it's just not syncing.  i think it has to do with audacity only lets you go a few digits on the % change.
justink, make sure you are using 2.1.0, it utilizes all the significant digits in your multiplier

Versions after that are found to truncate your digits.  Why the team chose to break something that works is beyond any explanation
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: justink on October 04, 2016, 07:10:15 PM
i just can not figure this out... i feel like i'm doing all the math correctly but it's just not syncing.  i think it has to do with audacity only lets you go a few digits on the % change.
justink, make sure you are using 2.1.0, it utilizes all the significant digits in your multiplier

Versions after that are found to truncate your digits.  Why the team chose to break something that works is beyond any explanation

i am... for some reason it lets me put them in but then when i bring it up again, it truncates it down to three decimal places...  which is kinda huge actually.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: capnhook on October 04, 2016, 10:24:30 PM
Yeah.  You have to paste the factor back in each time you use the tool, or it chops your digits off.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: andyjah on October 06, 2016, 04:52:34 PM
i just can not figure this out... i feel like i'm doing all the math correctly but it's just not syncing.  i think it has to do with audacity only lets you go a few digits on the % change.
justink, make sure you are using 2.1.0, it utilizes all the significant digits in your multiplier

Versions after that are found to truncate your digits.  Why the team chose to break something that works is beyond any explanation

Is there any way to switch back to an older version? I am running the newest version and have been having the same issue as Justin
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: morst on October 07, 2016, 04:03:17 AM
Here is a link to mac and windows versions of Audacity 2.1.0:
https://sourceforge.net/projects/audacity/files/audacity/2.1.0/

Is there any way to switch back to an older version? I am running the newest version and have been having the same issue as Justin
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: justink on October 07, 2016, 10:42:12 PM
Yeah.  You have to paste the factor back in each time you use the tool, or it chops your digits off.

it won't let you paste...  lol
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: dynamicalories on May 18, 2017, 03:28:19 PM
Anyone have directions for doing this in Adobe Audition CC? I've got an AUD source and SBD source recorded on 2 different recorders. I could always just use the directions here but was wondering if this might be easier in Audition.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: dynamicalories on May 21, 2017, 08:02:38 AM
Damn, this works perfectly in Audacity. Thanks @morst. I'm no longer going to fear using 2 recorders for SBD/AUD if need be.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: morst on May 22, 2017, 02:22:32 AM
Damn, this works perfectly in Audacity. Thanks @morst. I'm no longer going to fear using 2 recorders for SBD/AUD if need be.
Fantastic news!  :clapping: :clapping: :clapping:

However, this sounds really cruel...
Yeah.  You have to paste the factor back in each time you use the tool, or it chops your digits off.
    :o
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: capnhook on May 22, 2017, 08:48:29 AM
Yeah, stick with version 2.1.0 to avoid this, for now.....maybe some clear heads will fix this.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: nak700s on August 14, 2017, 02:58:04 PM
Thank you...I can't wait to give this a try.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: Humbug on September 07, 2017, 02:44:22 AM
This thread is great - I spent an hour trying to line up a two hour matrix last night in 2.1.3, and figured out 3DP wasn't enough. Came here, downloaded 2.1.0, and I'm back on with the task.

Has anyone informed the Audacity team? 
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: justink on September 07, 2017, 09:51:08 AM
This thread is great - I spent an hour trying to line up a two hour matrix last night in 2.1.3, and figured out 3DP wasn't enough. Came here, downloaded 2.1.0, and I'm back on with the task.

Has anyone informed the Audacity team?

probably not.  we definitely need a fix.  i still can't figure it out.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: Humbug on September 07, 2017, 02:48:39 PM
Messaged the Audacity team on Facebook this evening; will post if I hear back.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: JiB97 on October 26, 2017, 07:49:22 PM
posting in here so I can reference later.

been having issues recently combining sources; everything is coming out clipping even when both source are max peaking @ -4.  wish there was a program where I could tell it to have source A @ 60% and source B @ 40%...
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: bvaz on October 27, 2017, 07:06:24 AM
posting in here so I can reference later.

been having issues recently combining sources; everything is coming out clipping even when both source are max peaking @ -4.  wish there was a program where I could tell it to have source A @ 60% and source B @ 40%...
I usually play the file in audacity at spots and look at the meters to see how high it is hitting before exporting.  not full proof, but it gives me an idea.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: Life In Rewind on October 27, 2017, 08:05:03 AM
posting in here so I can reference later.

been having issues recently combining sources; everything is coming out clipping even when both source are max peaking @ -4.  wish there was a program where I could tell it to have source A @ 60% and source B @ 40%...

Percentages aren't very useful or meaningful...use your ears.

And yes - its normal to have higher peaks when combining sources.

Solutions are - record in 24 bit and don't run so hot. (like -8db instead of -4db)

Or - once you have your mix - use the faders (on the left) to reduce the gain by equal amounts on each file set.

Just nudge each one down by 1db until the peaks go away.

Then export!
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: morst on February 14, 2018, 02:11:40 PM
posting in here so I can reference later.

been having issues recently combining sources; everything is coming out clipping even when both source are max peaking @ -4.  wish there was a program where I could tell it to have source A @ 60% and source B @ 40%...
I usually play the file in audacity at spots and look at the meters to see how high it is hitting before exporting.  not full proof, but it gives me an idea.
You can also just quickly render the peak area, so you don't have to wait for the whole thing to run, just to find out that the hot part went over!?

Run a test render, import it, if it peaks, lower everything & repeat. If the test doesn't peak, then render the whole thing, import and check for peaks!
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: nak700s on February 15, 2018, 12:20:59 PM

been having issues recently combining sources; everything is coming out clipping even when both source are max peaking @ -4.  wish there was a program where I could tell it to have source A @ 60% and source B @ 40%...
I usually play the file in audacity at spots and look at the meters to see how high it is hitting before exporting.  not full proof, but it gives me an idea.
[/quote]
You can also just quickly render the peak area, so you don't have to wait for the whole thing to run, just to find out that the hot part went over!?

Run a test render, import it, if it peaks, lower everything & repeat. If the test doesn't peak, then render the whole thing, import and check for peaks!
[/quote]

It isn't brain surgery, it's post production.  Experiment and write down what you do.  After doing it a couple times, you will know where to have the levels on all tracks.  If it helps, the way that I find works best for me is to use my ears and eyes.  In that order!  I listen to determine which tracks I want louder...or possibly the same.  Once I figure that out, it's easy from there.  When initially recording the show, I record low (ALWAYS at 24bit)... ideally peaking around -12db or lower.  I raise the tracks (or lower them if the band got crazy loud or the board patch was unmanageable during the show) to have the mix I want.  An example, being the last show I did, the board patch was brought to -5.5db and the microphone tracks were brought to -8.5db.  I liked the mixed ratio with the soundboard being a little more dominant in this case, but it isn't always like that for me.  From there, I export and save my work.  In this stage, I have gotten used to where to adjust my levels to so they are not peaking when combined.  Now I have two files in that folder, the original (which I will never delete) and the work in progress.  From there, I basically start over, opening up a new Audacity window, and dropping that new file into it for further editing.  This is where I do the bulk of my post work.  If there are only a few spikes, I'll bring them down (by highlighting the spike, then hitting the "+ magnifier" symbol 9-10 times, I isolate the spike to the point that I'm ONLY reducing that one jump in volume).  Once I'm happy with that stage, I bring both tracks up to -0.50db (some prefer -1.0db, while others prefer 0.00db.  I say too each their own on that point).  From there, if I'm happy, I'm almost done...but let's be honest here, I'm never happy at that point!  I will look at spikes, if there are whistles or screams, etc. to see what else needs to be done.  It is at this stage that a normal human being will normalize or use other features to essentially compress the music and give a more uniform wave.  I do not do this.  Ever.  I like the dynamic range of the live show and do my best to keep the highs and lows, while only eliminating the spikes to bring up everything else to a good volume.  This may sound like normalizing or compressing, but when I reduce a dozen or so spikes, around 1/1000 sec each, throughout one set, in order to bring everything else up, it is very different.  Once I've finished this, I will individually bring up the two tracks to -0.50db if they aren't already there.  Once this is finished, I like to do a 10 second fade in and fade out before saving this now completed file.  I prefer to track out the songs in CDWave...
And that, boys and girls, is how I have figured out how to reduce my 4-5 channel recordings down to a two channel recording that I can burn to CD, share, email to the band, etc.  I hope my step by step is helpful (and that I didn't leave something out because I take it for granted). 
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: morst on February 18, 2018, 07:12:23 PM
  From there, if I'm happy, I'm almost done...but let's be honest here, I'm never happy at that point!  I will look at spikes, if there are whistles or screams, etc. to see what else needs to be done.  It is at this stage that a normal human being will normalize or use other features to essentially compress the music and give a more uniform wave.  I do not do this.  Ever.  I like the dynamic range of the live show and do my best to keep the highs and lows, while only eliminating the spikes to bring up everything else to a good volume.  This may sound like normalizing or compressing, but when I reduce a dozen or so spikes, around 1/1000 sec each, throughout one set, in order to bring everything else up, it is very different.
Please correct me if I am wrong, but AFAIK, normalization is arithmetic and linear. Compression is decidedly NOT linear. They are very different.

My super-detailed approach involves making a test mix just a LITTLE hotter than I think I can get away with. I then import it, and find volume spikes that cause over-level peaks in the current render. I then lower those peaks manually, one at a time. I usually use the "amplify" plugin with a negative value like -1 or -3 dB. Once I have done this, I bounce a new mix and compare to make sure I got 'em all! If there are more than 10-100 peaks, I just master it a little lower, depending on how much work I want to put in for that last little bit of diminishing returns!!!
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: noahbickart on February 19, 2018, 10:45:52 AM
Peak Normalizing does not affect dynamic range.

“Eliminating peaks” = limiting. This is, by definition, a reduction of dynamic range.

I see no problem with either depending on the circumstances. But I know you are anti compression.

If so, why do the latter but not the former?
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: nak700s on February 19, 2018, 12:56:38 PM

Please correct me if I am wrong, but AFAIK, normalization is arithmetic and linear. Compression is decidedly NOT linear. They are very different.

My super-detailed approach involves making a test mix just a LITTLE hotter than I think I can get away with. I then import it, and find volume spikes that cause over-level peaks in the current render. I then lower those peaks manually, one at a time. I usually use the "amplify" plugin with a negative value like -1 or -3 dB. Once I have done this, I bounce a new mix and compare to make sure I got 'em all! If there are more than 10-100 peaks, I just master it a little lower, depending on how much work I want to put in for that last little bit of diminishing returns!!!
[/quote]

I'm not sure what the difference is, or if there even is one.  This is how I learned to do my edits and I like the results.  I wouldn't mind an easier way, but not at the expense of my recording.  What we do doesn't seem much different, I just prefer to minimize the redlines, although it happens and I lower them the same way you described at 1db at a time.


Noah:
"Peak Normalizing does not affect dynamic range.
“Eliminating peaks” = limiting. This is, by definition, a reduction of dynamic range."

I'm not debating "Peak Normalizing" because it isn't something I know enough about.  Perhaps you or someone can give me an explanation of this so I can better understand the differences as compared to what I do now.
However, I will argue that what I do by reducing a few peaks (as defined by me as spikes that are high enough, like a single overenthusiastic drum beat, to keep the balance of the recording down at a lower than desirable level, but did not necessarily peak or redline during live recording.) is not the same as using a limiter, which will essentially cap off the recording level causing an almost automatic compression by keeping all of the highest peaks at the same level, thereby eliminating much of the dynamic range.  The only time I use a limiter is in a stealth situation where I have to set and forget my levels.  I'll still set them low, in hopes of never utilizing the limiter's function, but know it's there just in case.  Noah, you have seen how I record...do you really think I peak out at a live show?
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: Gutbucket on February 19, 2018, 03:16:24 PM
I will argue that what I do by reducing a few peaks (as defined by me as spikes that are high enough, like a single overenthusiastic drum beat, to keep the balance of the recording down at a lower than desirable level, but did not necessarily peak or redline during live recording.) is not the same as using a limiter

What you describe above is the same as limiting with the threshold set to only catch the most excessive peaks.  The only difference is that you are selecting and reducing each peak manually, rather than having the limiter algorithm find them (as determined by the threshold value) and reduce them (the reduction ratio value) for you automatically.

Quote
.. is not the same as using a limiter, which will essentially cap off the recording level causing an almost automatic compression by keeping all of the highest peaks at the same level, thereby eliminating much of the dynamic range.

That's describing a much lower threshold setting which captures not just a few excessive peaks, but is effecting most peaks.

Both are "limiting peak excursions" and reducing dynamic range, as is your manual reduction technique.  The difference is simply one of degree based on different settings of the limiter (or your manual process), but are otherwise fundamentally the same process.




"Normalization" is simply an automated way of raising the level of the entire file by a certain value, where the normalization routine helps determine what that value should be to get the result you want.  It is a linear process and does not affect dynamic range - it raises the level of everything by the same amount.  Normalization with regards to the polishing of music files for release means "peak normalization", where the highest peak value is of interest (to avoid it going over) even though everything is being increased by the same value across the board.   It is the same as manually finding the highest peak, figuring out how much you can increase the signal level of the entire file by to increase everything as much as you want, and applying that amplification.

Sometimes you may hear of "RMS normalization."  This is also linear.  The only difference is that the RMS value of the signal is what is monitored instead of the peak values.  This is useful for matching the average energy level of two files for comparison so that they both have the same loudness so you don't deceive yourself by preferring the otherwise consciously imperceptibly louder one (RMS correlates to loudness much better than peak values).  But RMS normalization is not what you'd want to use to raise the level of your files so that the peaks are just below full-scale, as you don't really know where the peaks land until you render it.  It can accidentally cause overs since the highest RMS value will always be lower than the highest peak value and the two are not strongly correlated.

To complicate things, some programs will combine RMS normalization with a secondary limiting function to avoid overs when the RMS value is pushed to high.  This is two separate functions being applied on one step.  The second limiting function limits the dynamics, the RMS normalization it self does not.

Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: nak700s on February 19, 2018, 04:40:56 PM
I will argue that what I do by reducing a few peaks (as defined by me as spikes that are high enough, like a single overenthusiastic drum beat, to keep the balance of the recording down at a lower than desirable level, but did not necessarily peak or redline during live recording.) is not the same as using a limiter

What you describe above is the same as limiting with the threshold set to only catch the most excessive peaks.  The only difference is that you are selecting and reducing each peak manually, rather than having the limiter algorithm find them (as determined by the threshold value) and reduce them (the reduction ratio value) for you automatically.

Quote
.. is not the same as using a limiter, which will essentially cap off the recording level causing an almost automatic compression by keeping all of the highest peaks at the same level, thereby eliminating much of the dynamic range.

That's describing a much lower threshold setting which captures not just a few excessive peaks, but is effecting most peaks.

Both are "limiting peak excursions" and reducing dynamic range, as is your manual reduction technique.  The difference is simply one of degree based on different settings of the limiter (or your manual process), but are otherwise fundamentally the same process.




"Normalization" is simply an automated way of raising the level of the entire file by a certain value, where the normalization routine helps determine what that value should be to get the result you want.  It is a linear process and does not affect dynamic range - it raises the level of everything by the same amount.  Normalization with regards to the polishing of music files for release means "peak normalization", where the highest peak value is of interest (to avoid it going over) even though everything is being increased by the same value across the board.   It is the same as manually finding the highest peak, figuring out how much you can increase the signal level of the entire file by to increase everything as much as you want, and applying that amplification.

Sometimes you may hear of "RMS normalization."  This is also linear.  The only difference is that the RMS value of the signal is what is monitored instead of the peak values.  This is useful for matching the average energy level of two files for comparison so that they both have the same loudness so you don't deceive yourself by preferring the otherwise consciously imperceptibly louder one (RMS correlates to loudness much better than peak values).  But RMS normalization is not what you'd want to use to raise the level of your files so that the peaks are just below full-scale, as you don't really know where the peaks land until you render it.  It can accidentally cause overs since the highest RMS value will always be lower than the highest peak value and the two are not strongly correlated.

To complicate things, some programs will combine RMS normalization with a secondary limiting function to avoid overs when the RMS value is pushed to high.  This is two separate functions being applied on one step.  The second limiting function limits the dynamics, the RMS normalization it self does not.

Thank you for the explanation.
I'm not sure if I was initially clear as to what I do to bring my levels up or down.  When doing so over the entire file, nothing is altered other than the "saturation".  More often than not, I'm raising the level of an entire file (set) by + "Xdb" (or lowering if I'm balancing out multiple tracks to blend a certain way...more live mics or more soundboard...).  When I refer to spikes, I'm thinking in terms of those random drum beats, a blast of feedback from an instrument (which I'll try to reduce even more), a thud on a microphone, etc. that are causing the entire set to be lower than I'd like.  Here comes the part that I may not have been clear on:  I don't uniformly drop those spikes to match the next highest levels, I reduce them by 1db - 3db depending on their severity, essentially maintaining their higher level, just not as a "run-away" spike.  Does that make more sense?  I know I'm thinking of what I do (I'm at work now), but may still be leaving out some fine details.  When I do this, I do it individually as to maintain their relation to the rest of the music.  I don't just say, "OK, I'll reduce these few spikes to X", but rather I may reduce one by 2db, and another by 1db, allowing me to bring the entire file up another couple db's.  So, if I used the normalization feature instead, wouldn't that all be done at a single level, say 1db for example?
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: Gutbucket on February 19, 2018, 06:51:43 PM
Okay to be clear, you are doing three things-
1) identifying the offending peaks
2) reducing the level of those peaks by some amount
3) raising the level of the entire file into the "now unused top part of the scale" where you've made more room via lowering the highest peaks.

The first two steps are limiting.  The third is normalization, regardless of if you are doing all this manually or using a limiter and normalization algorithms to assist you.

Okay, now the details-
Quote
When doing so over the entire file, nothing is altered other than the "saturation".  More often than not, I'm raising the level of an entire file (set) by + "Xdb" (or lowering if I'm balancing out multiple tracks to blend a certain way...more live mics or more soundboard...). 
  ^This describes manual normalization.

Saturation is a magnetic tape term.  Good magnetic tape saturation meant finding an appropriate balance between low-level tape hiss noise at low saturation levels and non-linear compression effects at high saturation levels.  Digital audio is linear and does not suffer (or benefit depending on your perspective) from those distortions.  It's just digital level, measured in terms of dBfs (decibels, full scale) where 0 dBfs is the highest level possible without clipping distortion.  Normalization raises the level of everything equally to closer to 0dBFS.  It's good practice to leave a small buffer of a dB or so at the top, with the highest peaks topping out at a few dB below full-scale, say -2dBfs or whatever, since that can avoid something called intersample-overs, where the reconstructed analog waveform my occasionally clip even though the highest sample value to either side of that peak is actually below 0dBfs.

Quote
I don't uniformly drop those spikes to match the next highest levels, I reduce them by 1db - 3db depending on their severity, essentially maintaining their higher level, just not as a "run-away" spike.  Does that make more sense?  I know I'm thinking of what I do (I'm at work now), but may still be leaving out some fine details.  When I do this, I do it individually as to maintain their relation to the rest of the music.  I don't just say, "OK, I'll reduce these few spikes to X", but rather I may reduce one by 2db, and another by 1db, allowing me to bring the entire file up another couple db's.  So, if I used the normalization feature instead, wouldn't that all be done at a single level, say 1db for example?

^
Okay so this is the limiting steps (finding and lowering the peaks), not the normalization part (raising the level of everything) which is applied after the peaks are lowered.  The threshold control on the limiter is the detector which determines what will be affected.  Only the peaks which exceed the threshold setting might be affected (might depends on other settings of the compressor/limiter.  If limiting, might becomes probably or definitely (which is partly what differentiates limiting from compression).  The threshold is only a sensor.  It does not affect the sound itself.  It's just doing the identification of peaks part.  Part 1) in the list above.

The limiter's compression ratio and time-constraint settings (attack time, release time, and on a digital limiter- look ahead) affect how the peaks which are detected as exceeding the threshold are reduced and by what amount.  Limiting implies a high compression ratio and a very short attack time to more aggressively control excursions above the threshold.   A short attack time catches the shortest onset peaks, (look ahead essentially enables the ability to achieve an zero or immediate attack time, catching everything).

The ratio determines how much reduction in level is applied above the threshold.  Unless the ration is set to infinite, it won't crush all peaks to exactly the same peak level, unless its a "brickwall limiter" intended to absolutely never let anything exceed a certain peak value (which in essence is infinite compression with zero attack time above the threshold).  Instead it turns down the level by the ratio amount.  So a larger peak and a lower one, both of which exceed the threshold value, will still peak at different levels, but both will be reduced by a percentage of their original value.


Here's the thing- It can be hard to wrap your head around all these settings to determine exactly what the limiter (or compressor - they are the same thing essentially, only differing by degree in settings) is doing.  It can do what you describe, but when you go in and manually find each peak and manually reduce it, you know exactly which peaks are being targeted and by how much they are each being reduced.  The trade off is between the effort to do that manually verses developing the skill of how to set the limiter to do the same thing.  Those who really know their way around compression and limiting and do it well (not the loudness war casualties) will often use several passes instead of just one pass of compression and or limiting, catching only the very highest peaks with a more aggressive setting while perhaps using a less aggressive setting with a slightly lower threshold on a seperate pass to sort of "feather" the reduction and make it more transparent.

None of this is to argue that you should do it this way.  Do what works for you and you are comfortable with.  It is only to explain that limiting and normalization can be done manually or with limiting and normalization tools, but is essentially the same process.  Like musical performance and like taping itself, the quality of the end results depends more on the operator and how one uses the tools available to them rather than the tools themselves.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: nak700s on February 19, 2018, 07:15:55 PM
^^ OK, that was helpful information.  Thank you for taking the time to explain it to me   :)
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: morst on February 19, 2018, 07:34:12 PM
^^ OK, that was helpful information.  Thank you for taking the time to explain it to ALL OF US   :)

Fixed that for us!  :D
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: Gutbucket on February 19, 2018, 07:47:28 PM
I just hope that helps more than obfuscates!
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: nak700s on February 23, 2018, 01:30:31 PM
I just hope that helps more than obfuscates!

It does...and apparently for more than just me  :)
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: morst on June 24, 2018, 02:24:56 PM
Bumping a favorite old reference topic here, so that I can share my calculator with all of y'all.

I thought I posted my handy spreadsheet link on this thread so folks could enjoy it but I can't seem to find it, so here it is, the morst-audio-speed-converter.

https://docs.google.com/spreadsheets/d/1pQGfYwPgBFFzcY5m6aRj-Zbu9HsRumLy-tJB1d8Eufg/edit#gid=583050244 (https://docs.google.com/spreadsheets/d/1pQGfYwPgBFFzcY5m6aRj-Zbu9HsRumLy-tJB1d8Eufg/edit#gid=583050244)

If you can't use it live in a browser, just download it and use it at home in LibreOffice, OpenOffice, or any Excel equivalent.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: ycoop on January 14, 2019, 06:50:53 PM
Let me give it a try for ya. These instructions should work fine on a mac or a PC running Audacity. Probably Linux too, though I have never tried it.

1- Run the masters so the levels peak below -3.0 dB on each if you can, so you can mix them without having to lower volume to avoid clipping peaks. Run them both at the same sample rate. Bit depth is not as important to match. Name each file descriptively including the type of source (Foobar2008-04-29-SBD-24bit.wav, Foobar2008-04-29-DPA-24bit.wav or some such)

2- Go to AUDACITY>PREFERENCES> QUALITY and set your default sample rate and bit depth to the desired settings (44100 with the desired output bit-depth). PROJECT>IMPORT both sources into audacity and FILE>SAVE your work.

3- Use the double-headed arrow "TIME SHIFT" tool in the top left corner (<-->) to line up the files as near as possible to the start of the music. Find a sharp peaking impulse like a drum hit or some other peak to line up and zoom in until they are as precisely aligned as possible.

4- If you think you need to do any EQ or level changes on either source, do this now. You can use EFFECT>AMPLIFY to tell you how high each source peaks. If each source peaks higher than -3.0dB at any point, you will get clipping on the mix, so you'll need to lower levels to avoid this. It is also possible to have one source higher than the other and still clip peaks. I am good but not great at math, so hopefully some other folks can chime in with suggestions and comments regarding levels. I think I have it right, that 2 signals of -3.0dB will add up to peak at -0.0dB so you want to stay below that.

5- Go to the end of the files and figure out how much they have drifted apart. Do some math* to figure out how much you need to use EFFECT>CHANGE SPEED to get them lined up (see below for my method of calculating the percent change)

6- I suggest shortening the longer file rather than stretching the shorter one, but it probably doesn't matter. Use the EFFECT>CHANGE SPEED to do that.

7- Check the alignment to make sure the sources stay together. If they are not correct, use EDIT> UNDO SPEED CHANGE and try step 6 again. When they are correct, FILE>SAVE your work again. As long as you keep the file open, you can UNDO past the file save operation, but once you close and open it again, you can't go back past the saved version.

8- Check the mix for sound by using the MUTE function on each track during playback to make sure it sounds good. Adjust the gain for each track if needed by using the +......- slider on the left of each track for course adjustment, or EFFECT>AMPLIFY for finer control.

9- Go to AUDACITY>PREFERENCES > QUALITY > HIGH-QUALITY DITHER and select "Triangle Dither"

10- FILE>EXPORT AS WAV (or AIFF) to make the mixed file. FILE>SAVE again. If you think you might need to make further adjustments after checking the completed file, keep this project session open so you can UNDO back. Name the file something descriptive like Foobar2008-04-29-MIX-24bit or Foobar2008-04-29-MATRIX-16bit so you can distinguish it from each source file.

11- FILE>OPEN a new Audacity project document and PROJECT>IMPORT the newly created mix file. EFFECT>AMPLIFY to check that all peaks are below -0.0dB. If this plugin does not offer to boost levels, then you probably have clipped a peak somewhere, and you will want to go back to the original files and lower the levels of one or both sources to preserve your dynamics and avoid flattening out peaks. If you have a little headroom and it sounds good, then you have successfully mixed your sources.

12- If you want to track for CD's, then VIEW>SET SELECTION FORMAT > CDDA min:sec:frames 75fps and then EDIT>SNAP TO> SNAP ON to allow you to cut tracks without "sector boundary errors." Select tracks in order by using EDIT> MOVE CURSOR TO TRACK START (I go into preferences and give it a keyboard shortcut to make this easier) then shift-clicking on the end of each track, then EDIT> SPLIT each track apart in order, making sure to split the final track too.

13- FILE> EXPORT MULTIPLE (NUMBERING CONSECUTIVELY) to WAV (or aiff) in your selected target directory.

14- Compress these files losslessly using your favorite FLAC encoder, and upload to your favorite sharing website, and post in the KICKDOWNS thread here so we can check it out.

15- please let me know if this is unclear or can be improved upon.  8)


* oh shoot, now I gotta figure out how to tell you the math part! My apologies for the half-assed nature of this part of my method.  :-[ Go to VIEW>SET SELECTION FORMAT > SAMPLES (SNAP TO SAMPLES) so you can measure the length of your program in samples. Measure the total length from your sync points early in the file to the desired sync points late in the file. You will get different numbers for each file since they are probably not lined up perfectly due to slight variances in the clock chips of the two recorders. Make a note of each of these numbers. Subtract one from the other to find out the number of samples of drift at the end, and write this number down. Divide the length of the longer one by the length of the shorter source and you will get a number close to but greater than 1.0000000. Let's use an example where you have exactly one second of drift at the end of exactly one hour at 48KHz. The longer file is now 172,848,000 samples and the shorter one is 172,800,000 samples. Divide the long one by the short one and you will get 1.0002788. (If I am getting this right, then) this tells you that you that you need to speed change the longer file by -.02788%

Damn I hope I got that right. Please won't someone troubleshoot my math and let me know the best way to do this???  :o

I tried unsuccessfully to use this method. Is your approach to align the sources at the start of the recording and then choose a spot later in the tracks that is the same point in “time” though it will not align perfectly?
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: capnhook on January 14, 2019, 06:56:55 PM
Are you using Audacity V2.1.0?
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: ycoop on January 14, 2019, 07:22:18 PM
Are you using Audacity V2.1.0?

I believe I’m using 2.3.0 (not at home now).
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: capnhook on January 14, 2019, 08:01:57 PM
I always have to time stretch my portable recorder files (I usually put it on the SBD), and I found once ago that some of the newer Audacity versions didn't use all the significant digits I inputted....the stretch turned out wrong with some newer versions of Audacity.

The "Change Speed" function would internally truncate a value like 0.0034819382974327 into just 0.00348.  You need all those other digits for a perfect stretch.  I was pulling my hair out until I figured out what was causing the bad stretches.

I haven't checked any of the really new versions, V2.1.0 suits me fine.  I don't know why the developers de-tuned the "Change Speed" tool, because it worked perfectly.

PM me if you would like a clean V2.1.0.  I can WeTransfer it to you.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: morst on January 14, 2019, 08:59:32 PM

I tried unsuccessfully to use this method. Is your approach to align the sources at the start of the recording and then choose a spot later in the tracks that is the same point in “time” though it will not align perfectly?
I would probably explain this a little differently now that it's 10.5 years later but the basics are still about the same.


1. Pick a spot near the beginning where you can line them up, and do so.
2. Mark the spot, and mark the start of both files so you can tell how much they move in step 3
3. Pick a spot near the ending where you can line them up, and do so.
4. Mark the spot, and mark the start of both files so you can tell how much they moved since step 2
5. use these spots to calculate the total length of time between the marked sync points from steps 1 & 3, and use the marked starts to compare how much you had to shift
6. do math
7. stretch or squash according to the math in step 6
8. sync at one of the spots, and then check the other. Should be correct if you got the math right. Watch out for the negative sign!


* always remember to save your work
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: ycoop on January 14, 2019, 09:30:24 PM

I tried unsuccessfully to use this method. Is your approach to align the sources at the start of the recording and then choose a spot later in the tracks that is the same point in “time” though it will not align perfectly?
I would probably explain this a little differently now that it's 10.5 years later but the basics are still about the same.


1. Pick a spot near the beginning where you can line them up, and do so.
2. Mark the spot, and mark the start of both files so you can tell how much they move in step 3
3. Pick a spot near the ending where you can line them up, and do so.
4. Mark the spot, and mark the start of both files so you can tell how much they moved since step 2
5. use these spots to calculate the total length of time between the marked sync points from steps 1 & 3, and use the marked starts to compare how much you had to shift
6. do math
7. stretch or squash according to the math in step 6
8. sync at one of the spots, and then check the other. Should be correct if you got the math right. Watch out for the negative sign!


* always remember to save your work

Thanks for the updated guidance, I’ll give it another go when I have that 2.1.0 copy.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: morst on January 20, 2019, 04:29:09 PM
Thanks for the updated guidance, I’ll give it another go when I have that 2.1.0 copy.
This website appears to have legacy audacity versions, including 2.1.0
https://www.videohelp.com/software/Audacity/old-versions
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: capnhook on January 21, 2019, 04:15:51 PM
Thanks for the updated guidance, I’ll give it another go when I have that 2.1.0 copy.
This website appears to have legacy audacity versions, including 2.1.0
https://www.videohelp.com/software/Audacity/old-versions

Looks legit, good find morst.  :coolguy:
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: nak700s on January 25, 2019, 12:26:26 PM
After almost 2 years, I was finally able to get IT to install Audacity on my work computer so I can edit shows in my down time at work.  He installed the latest version, 2.3.0, which I can't stand!  I can't seem to export in anything other than the entire multi-track or a mono track.  Ahhh, no!  Is the older 1.3 Beta version still available for download?  I figure that if the program is already on the computer, I should be able to replace it with an older version, no?
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: capnhook on January 25, 2019, 01:43:56 PM
Get V2.1.0, and don't look back.  There is a good link above ^^^ that morst found for us.

If not, I can WeTransfer you a copy.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: nak700s on January 25, 2019, 02:15:26 PM
Get V2.1.0, and don't look back.  There is a good link above ^^^ that morst found for us.

If not, I can WeTransfer you a copy.

Thank you, I'll give that one a try...it certainly can't be worse than 2.3.0.  I can't believe I can't export a stereo file with the latest version!
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: capnhook on January 27, 2019, 10:58:30 PM
Thanks for the updated guidance, I’ll give it another go when I have that 2.1.0 copy.
This website appears to have legacy audacity versions, including 2.1.0
https://www.videohelp.com/software/Audacity/old-versions

Looks legit, good find morst.  :coolguy:

Here's another site for V2.1.0:

https://sourceforge.net/projects/audacity/files/audacity/2.1.0/



Make great tapes.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: nak700s on January 29, 2019, 02:30:15 PM
I wasn't able to install it myself...unfortunately, IT would need to do it for me.  Next time he's around, I'll ask.  In the meantime, I just have to do my editing at home.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: Papaphunk on February 14, 2019, 09:08:34 AM
Trying to mix a SBD and AUD source together from the weekend shows...This can be maddening.

I've listened to the same joke in between songs 2 and 3 about 50 times this week trying to align these 2 files  :banging head:
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: capnhook on February 14, 2019, 09:32:14 AM
TRIM, and Line up the starts exactly, and then stretch one of them.  You have to use V 2.1.0, or it won't work.  V 2.3.0 Change Speed is wrong, and will have you pulling your hair out for sure.


I can help you if you get stuck, if you want to WeTransfer the files.  Hang in there, you'll get it.

Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: nak700s on February 14, 2019, 10:42:39 AM
^^^ This is why I love TS so much ^^^

 :coolguy: :clapping: :coolguy:
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: Papaphunk on February 19, 2019, 10:16:46 AM
TRIM, and Line up the starts exactly, and then stretch one of them.  You have to use V 2.1.0, or it won't work.  V 2.3.0 Change Speed is wrong, and will have you pulling your hair out for sure.


I can help you if you get stuck, if you want to WeTransfer the files.  Hang in there, you'll get it.

Success! Thanks Capnhook  :coolguy:

https://archive.org/details/DonnaTheBuffalo2019-02-08.SBD.Matrix.Flac16
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: TheBishop on May 20, 2020, 12:44:47 PM
I'm having a hell of a time right now...

The venue that I have been recording at has given me access to their soundboards so that I can mix them with my audience recordings.  Awesome!  So I take the SBD (recorded at 48k) and my AUD (also recorded at 48k) and load them in to Audacity v2.1 (I was using the newer version until I read this thread so I uninstalled that and installed 2.1).  I lined both of the recordings up at the 0:00:03.725 (178,791 samples) point and then find a common point towards the end of the show, for the soundboard this is 2:12:43.275 (382,237,217 samples) and for the audience this is 2:13:05.196 (383,289,428 samples).  I use morst's Audio Speed Converter spreadsheet:

(https://i.imgur.com/lveShFB.jpg)

and I get a % speed change of -0.27527696236864200000.  I put this in to Audacity (without the negative sign) and run the Change Speed effect on the audience recording:
(https://i.imgur.com/vhallzf.jpg)

This is where things get funky...

At 0:00:27 the recordings are off by 77 msecs
At 2:15:00 the recordings are off by 500 msecs
but at 1:08:00 the recordings are off by 6 seconds!

This is my first time trying to combine two sources and I'm going nuts.  I don't understand how they could be so close at either end of the show, but so far apart in the middle.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: morst on May 20, 2020, 02:31:24 PM
Listen carefully for a gap or discontinuity in the (shorter?) source which gets "ahead".
If there are breaks in one source, then it will require separate synchronization for each portion

The other thing to watch with sources like this which have two different sample rates is that you are counting samples for only the source you wish to change. The 44.1 source won't have the same number of samples in the same length of music as the 48k source so you have to be consistent in order for my spreadsheet math to work.

I suggest using the numbers of samples which refer to the source you need to stretch or squash. The other one is just your guide to get the points marked. If that's not clear, you could sample rate convert one source to match the other, but I usually shun additional steps when possible.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: voltronic on May 20, 2020, 03:07:19 PM
I think Bishop said both sources were 48 kHz.

Even with the same sample rate though, different converters in different boxes will drift relative to one another.  Being 6 seconds off after an hour isn't crazy, even if everything works as it is supposed to.  I have definitely seen it that bad before between two different 48 kHz sources.  The only way to avoid it is to  jam timecode on both devices and sync up in post, but that's not always an option.


Wouldn't the Change Tempo effect be a better choice than Change Speed, since the second one also changes pitch?
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: TheBishop on May 20, 2020, 03:21:41 PM
Morst,

Damn, you're pretty good.  Something happens with the SBD source a little after 14 minutes in and it loses 6 seconds.  Now I've got to work out exactly where and how long it is.

**Edit:** Just found another 5 second break in the soundboard at 37 minutes.  I think there are going to be one or two more.  There was about 22 seconds of what I thought was drift between the two files to begin with.

Also, to confirm, they were both 48k files.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: morst on May 20, 2020, 05:38:51 PM
I think Bishop said both sources were 48 kHz.

Even with the same sample rate though, different converters in different boxes will drift relative to one another.  Being 6 seconds off after an hour isn't crazy, even if everything works as it is supposed to.  I have definitely seen it that bad before between two different 48 kHz sources.  The only way to avoid it is to  jam timecode on both devices and sync up in post, but that's not always an option.

Wouldn't the Change Tempo effect be a better choice than Change Speed, since the second one also changes pitch?

HAHA yeah if I could have read more carefully I could have seen 48 for both... but I replied not having computed that.

Note that his timings show that he originally got it synced at the start and end, but then the middle was way off.
That's not normal, and is exactly what happened when I tried to mix sources on a bad DAT transfer so I recognized the issue.


as for CHANGE SPEED, yes, you need the pitch to change, although unless you have far better pitch than I do, you won't notice.
Change Tempo is for making advertisements where the announcer talks super fast but it's not like a chipmunk.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: voltronic on May 20, 2020, 09:09:37 PM
Note that his timings show that he originally got it synced at the start and end, but then the middle was way off.
That's not normal, and is exactly what happened when I tried to mix sources on a bad DAT transfer so I recognized the issue.
Well now it's my turn to have poor reading comprehension.  :cheers:

as for CHANGE SPEED, yes, you need the pitch to change, although unless you have far better pitch than I do, you won't notice.
Change Tempo is for making advertisements where the announcer talks super fast but it's not like a chipmunk.

I'm a bit confused by this.  Why would you want the pitch to change when you don't have to?  I get that it might be too small to notice, but still.  Are their artifacts introduced in Audacity's Change Tempo?  Other programs can do this with no ill effects.  I did this in Reaper earlier this week (admittedly a much more extensive app).
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: morst on May 21, 2020, 12:31:51 AM
I'm a bit confused by this.  Why would you want the pitch to change when you don't have to?  I get that it might be too small to notice, but still.  Are their artifacts introduced in Audacity's Change Tempo?  Other programs can do this with no ill effects.  I did this in Reaper earlier this week (admittedly a much more extensive app).
OK mental exercise:

Let's imagine that the decks are not close to one another at all, but rather their speed is off by something radical like a factor of 2!
We know that the audio will be a full octave apart.
Surely we need the pitch to be changed when the conversion takes place.


Two machines with entirely different ideas of how long one second takes will require some kind of transformation, in order for their outputs to match.


I have no idea if Change Tempo has artifacts, it's not at all what I have ever attempted to use, as it is made for a totally different purpose than I want.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: TheBishop on May 21, 2020, 02:40:45 PM
Welp, turns out after identifying those SBD dropouts everything lines up nicely and I don't even have to do a "Change Speed".  Hopefully the other files that they sent me don't have similar issues, but I've got a bad feeling.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: TheBishop on May 22, 2020, 03:02:03 PM
Here it is, my first matrix: https://archive.org/details/sof2019-12-07.mtx.flac2448/
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: morst on May 22, 2020, 08:55:27 PM
Here it is, my first matrix: https://archive.org/details/sof2019-12-07.mtx.flac2448/ (https://archive.org/details/sof2019-12-07.mtx.flac2448/)
Sounds fat! Nice going!!!
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: TheBishop on May 22, 2020, 09:55:11 PM
Thanks, I appreciate that. Next up is a Toubab Krewe show that I've been needing to master for several months now.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: morst on August 02, 2020, 03:30:14 PM
Bumping this thread, because I just re-wrote the instructions for my morst-Audio-Speed-Converter.XLSX spreadsheet, which is available for free download still at this link:
https://docs.google.com/spreadsheets/d/1pQGfYwPgBFFzcY5m6aRj-Zbu9HsRumLy-tJB1d8Eufg/edit#gid=583050244 (https://docs.google.com/spreadsheets/d/1pQGfYwPgBFFzcY5m6aRj-Zbu9HsRumLy-tJB1d8Eufg/edit#gid=583050244)


Quote
"This spreadsheet is a tool which can calculate the percent of ""Speed Change"" needed, in order to synchronize two uninterrupted audio tracks, made with different digital recorders which did not have timing clocks locked together.
This tool was made for use along with the Audacity workstation software. Audacity is availble as a free download for PC, MAC, and Linux. This tool's results can likely be used for other workstation software, as well."   


"Before using this tool, the user should precisely locate and mark four points within the two tracks to be synchronized, in order to make find the two values to feed this tool.
To make a track mark (label) in Audacity on PC, use the mouse and click the point in the track, then use Control-B keyboard shortcut, or go to Tracks > Add Label At Selection. On MacOS, it's Command B.
For greatest accuracy over long files, the two points at which the files are be synchronized should be as far apart in time as is practical, that is, one near the start of the shortest segment, and one near the end of it.
As each point is located and marked, the start time of the file to be changed should also be marked.
The two marked start times are where the difference in time between the sync points of the file to be changed may be most easily measured, as the waveform of the first spot moves from its marked location when the user finds the second spot.
Rather than having to find the same bit of the pattern to mark again, it is much easier to simply use the start of the track as a proxy.
If it is not practical to use the start times, the file end points may alternately be used."   
                                       
"To use this tool, the user enters two values, and the desired output is the Speed Change value (% differnce), which can then be used in the AUDACITY workstation software's Speed Change plugin, in order to synchronize the tracks.
The primary version on lines 4-5 allows the user to enter the length of the reference file, in samples, and the number of samples in between the marked start points. (see above)
The optional version on lines 9-10 allows the user to enter two track lengths, in samples. This might be useful for matching a soundtrack to the scratch audio of a video production, for instance, or making guesstimations"                                                                       


comments welcome?!
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: nak700s on July 05, 2021, 09:56:41 AM
I'm having a hell of a time right now...

The venue that I have been recording at has given me access to their soundboards so that I can mix them with my audience recordings.  Awesome!  So I take the SBD (recorded at 48k) and my AUD (also recorded at 48k) and load them in to Audacity v2.1 (I was using the newer version until I read this thread so I uninstalled that and installed 2.1).  I lined both of the recordings up at the 0:00:03.725 (178,791 samples) point and then find a common point towards the end of the show, for the soundboard this is 2:12:43.275 (382,237,217 samples) and for the audience this is 2:13:05.196 (383,289,428 samples).  I use morst's Audio Speed Converter spreadsheet:

(https://i.imgur.com/lveShFB.jpg)

and I get a % speed change of -0.27527696236864200000.  I put this in to Audacity (without the negative sign) and run the Change Speed effect on the audience recording:
(https://i.imgur.com/vhallzf.jpg)

This is where things get funky...

At 0:00:27 the recordings are off by 77 msecs
At 2:15:00 the recordings are off by 500 msecs
but at 1:08:00 the recordings are off by 6 seconds!

This is my first time trying to combine two sources and I'm going nuts.  I don't understand how they could be so close at either end of the show, but so far apart in the middle.

If this is something you plan on doing more often, may I suggest an equipment upgrade...  You may want to consider a 4-track deck that you can record 4 tracks internally.  I use the Sound Devices 744T, and there are several other great options as well, like their Mix-Pre series.  A long set of cables and you're now simultaneously recording all 4 tracks (a pair of mics + a stereo soundboard feed) on the 1 deck.  All four tracks will open in your editing program, and you'll decide what to bring up or down to your liking.  It's about 1000% easier!   :cheers:
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: checht on July 05, 2021, 11:51:50 AM
If this is something you plan on doing more often, may I suggest an equipment upgrade...  You may want to consider a 4-track deck that you can record 4 tracks internally.  I use the Sound Devices 744T, and there are several other great options as well, like their Mix-Pre series.  A long set of cables and you're now simultaneously recording all 4 tracks (a pair of mics + a stereo soundboard feed) on the 1 deck.  All four tracks will open in your editing program, and you'll decide what to bring up or down to your liking.  It's about 1000% easier!   :cheers:

^ this. 100% agree.
Went from Mix-Pre 3 to 6 for this reason. Had an old pair of mogami 100' cables, added some 50's & 20's from Tgadakis and everything got better. Next we can discuss the ultimate SBD connector field kit 😀.
Title: Re: Audacity (osx): How to mix two AUD sources?
Post by: morst on July 05, 2021, 03:10:32 PM
You can't always get a cable between the SBD and the best sounding spot, so this technique won't go away just yet.

OH FUCK this shit is all old and probably solved.
nevermind

That correction number is VERY large. Are you sure the stretch/squash requires six seconds of correction?
1052211 is a lot of samples...
Are you certain that both recordings are continuous? No pauses?
I think you should consider using the other set of lines in my spreadsheet and entering the length of the longer section as 382,058,426 and the difference as the number of samples between the early Sync track start point and the later Sync track start point
When you synced at the start and the end, please mark the locations of the file starts, and use the amount of change as the DIFFERENCE.
The length of time BETWEEN the points is only 382,058,426 samples, which I suggest to plug in as the "LONGER" Length.
(I am gonna have to rewrite this spreadsheet soon anyhow so it's good to get clarity/communication issues sorted out.)


** A note for clarity - the speed change is not computed based on the length of the entire fire.
The speed change is computed based on the number of samples between the two sync points on the longer source versus the number of samples between the two sync points on the shorter source.
I find it easier to count the long one and mark the shorter one's movement, which is why I use the set of lines in my sheet where I plug in length and difference.