Topic: Sync help needed (also: arrrrghhh I give up)

[acidjack]

I don't know what my problem is, but it seems I am just completely incapable of properly syncing two sources from different machines.  I've read the process; it's not rocket science.

But for some reason, for me, on multiple attempts, it just doesn't work.  I'm using Audacity. I have Audition, but I don't find it easier for doing this.

I have two files, about 90min long.  They have been properly aligned at the start.

Twice I set a sync point near the front and a sync point in the last 5min or so.

first attempt:

file 1 240 375 585 samples
file 2 240 370 630 samples

divide into each other, get 1.00002061
Shorten longer file by -.002061

Did not work.  Did not work when I attempted lengthening the shorter file either.

second attempt:

file 1 243 325 138
file 2 233 330 032

for a difference of 1.00002011 if you divide them into each other.

I tried shortening the longer file by -.002011, and it failed.

I didn't put this in "Computer" section mostly because at this point, I am just hoping some kind ts member can just do it for me.  Computer manipulation of the files has been a slow learning curve for me, and I am really frustrated.  I have the Audacity project file set up with everything but the actual math done.

If you can assist, or can figure out what I did wrong, pls PM me.

[page]

I'll reply here first in case anyone else is thinking about this just in case, if that doesn't work I'll PM you for the files and see if I can figure it out.

in general, some things I recommend:

1) Your sync points at the beginning/end should be the same frequency band if at all possible. The same snare is ideal.
2) I've found that while Audacity doesn't save more then 4 or 5 significant digits, I use all 11 or 12 just in case it will actually process them.
3) Sometimes I just have to fudge the math a bit after calculation. For example, instead of using -0.0001342455, I would actually use -0.0001352455 and play with it. I chalk it up to human error at the sample level of calculating the two lag values. The trick is figuring out which way to fudge it and by how much (bless the Undo Function).

If those three don't help, say so and I'll PM you for the files to see if I can help.

[eman]

What do you mean by "shorten by 0.002061" (off by 2 decimal pts BTW). 0.99997939 = 1/ 1.00002061 is this what you are using for the multiplication factor? Or you could multiply the other file by 1.00002061. Don't forget to realign after you do the stretch. If it doesn't work, adjust you number a little, note how much off it is when you do it. Not much fun, I know. I've only hit it perfectly on the first time a few times. Be patient, grasshopper.

[page]

What do you mean by "shorten by 0.002061" (off by 2 decimal pts BTW). 0.99997939 = 1/ 1.00002061 is this what you are using for the multiplication factor? Or you could multiply the other file by 1.00002061. Don't forget to realign after you do the stretch. If it doesn't work, adjust you number a little, note how much off it is when you do it. Not much fun, I know. I've only hit it perfectly on the first time a few times. Be patient, grasshopper.

I concur.

I've also only hit it on the first try a couple of times.

[acidjack]

What do you mean by "shorten by 0.002061" (off by 2 decimal pts BTW). 0.99997939 = 1/ 1.00002061 is this what you are using for the multiplication factor? Or you could multiply the other file by 1.00002061. Don't forget to realign after you do the stretch. If it doesn't work, adjust you number a little, note how much off it is when you do it. Not much fun, I know. I've only hit it perfectly on the first time a few times. Be patient, grasshopper.

Should have been more clear, the number for the shorten is a percentage, so hence, .00002061 becomes -0.002061%

Right?

[junkyardt]

look, I know some people like and respect doing it this way, with calculations using numbers to the 9th decimal place, etc., as the 'mathematically pure' way to do it. I tried it this way for a while, and ultimately found it to be too much lengthy trial and error, i.e. calculate, process file, sync...they don't sync right...recalculate, reprocess file, re-sync...still not quite right...repeat, etc. and ultimately, even after hour(s) of work this method often didn't even yield a properly synched result. now I use Vegas, and usually knock it out in 5-10 minutes or less.

[acidjack]

^ I suspect Vegas is much better for this, yes.  Unfortunately I'm on a Mac, so that's out 

[page]

^ I suspect Vegas is much better for this, yes.  Unfortunately I'm on a Mac, so that's out 

Exactly, If Vegas ran on anything other then Windows I'd consider it. I'm not dual booting just for doing mixes.
However, my frumpy indignation did cause me to go look up how it's done in Reaper:

Elastic Audio in Reaper Tutorial

Same principle of drag and stretch. Not Audacity, but it's a hell of a bargain compared to Vegas. Further research will be needed to see what sort of pitch adjustments are necessary, but it's an option if you don't want to do the time stretch thingy.

That said, if I could figure out how to do tracking on sector boundaries in Reaper, I'd probably pick up a license. I'm literally down to just mixing multiple sources and tracking a 16bit file in Audacity. All of my EQ, sample delay correction, noise reduction, etc are all handled elsewhere.

edit: fixed link.

[mattmiller]

What do you mean by "shorten by 0.002061" (off by 2 decimal pts BTW). 0.99997939 = 1/ 1.00002061 is this what you are using for the multiplication factor? Or you could multiply the other file by 1.00002061. Don't forget to realign after you do the stretch. If it doesn't work, adjust you number a little, note how much off it is when you do it. Not much fun, I know. I've only hit it perfectly on the first time a few times. Be patient, grasshopper.

Should have been more clear, the number for the shorten is a percentage, so hence, .00002061 becomes -0.002061%

Right?

Have you tried using r8brain to do the resampling?  I didn't have a lot of luck using CEP 2.0 because of the apparent lack of enough decimal places to make these small adjustments.  Now, I make my measurements in CEP and then use r8brain to resample.  I use 8 decimal places and have had tremendous success.

[hoppedup]

I tried shortening the longer file by -.002011, and it failed.

When you say shorten, you mean Change Speed command in Audacity, right? That's what I use.

The first couple of times I did this, I got confused with -/+ on the speed change. Haven't had any issues in quite some time. If you are trying to speed up (shorten) the longer source, you need to use a positive value. If you want to slow down the shorter file, use a negative value.

Like page, I'm not sure how many significant digits it recognizes but I enter as many as I can.

[Myco]

Now here's a reason why I like my DR-680, no need to deal with this issue any more.

[acidjack]

I tried shortening the longer file by -.002011, and it failed.

When you say shorten, you mean Change Speed command in Audacity, right? That's what I use.

The first couple of times I did this, I got confused with -/+ on the speed change. Haven't had any issues in quite some time. If you are trying to speed up (shorten) the longer source, you need to use a positive value. If you want to slow down the shorter file, use a negative value.

Like page, I'm not sure how many significant digits it recognizes but I enter as many as I can.

I do think that I may have gotten the speed change backwards (not thinking about that "speeding up" a file shortens it). 

page was kind enough to run it for me and got a slightly different number.  When I applied what he gave me, it worked.  I now think I have a pretty good handle on where I went wrong and will try this again in the future... unless a Vegas-like easy stretch method comes along for mac.

[page]

Now here's a reason why I like my DR-680, no need to deal with this issue any more.

I didn't know you could stealth wtih a 680. That's mildly impressive.   

Stealth mixes and running from the prime room/audience spot (which isn't located next to the sbd) are the last two places I'd consider resyncing, otherwise I agree, clocking is optimum. In this instance specifically, getting a clocked signal wasn't an option.

unless a Vegas-like easy stretch method comes along for mac.

Take a look at the Reaper link I posted earlier. I'm still learning myself (I'm on OSX as well) but it looks like it has potential. I'd be tempted to try double effort and do it both ways while I got used to the stretch method, just to see what caused the least amount of soundstage/detail smear (which I think is the biggest problem posed by doing clock-resyncs).

Short of redoing one of my mixes, I won't have an opportunity for a number of weeks to try it myself.

[jagraham]

I tried shortening the longer file by -.002011, and it failed.

When you say shorten, you mean Change Speed command in Audacity, right? That's what I use.

The first couple of times I did this, I got confused with -/+ on the speed change. Haven't had any issues in quite some time. If you are trying to speed up (shorten) the longer source, you need to use a positive value. If you want to slow down the shorter file, use a negative value.

Like page, I'm not sure how many significant digits it recognizes but I enter as many as I can.

^ This is a problem I had a few times.  I believe the thread where this is explained might be a little confusing because hoppedup is right that "change speed by -.xxxx" actually means you need to "speed up" the longer file with a positive value.  i found out what i was doing wrong by subtracting and i noticed that the difference in total samples had been doubled when it should have been cut in half.

in terms of significant digits i just use calculator on my PC and copy and paste all the numbers to be safe.  maybe thats a bad idea?

another concern here can be your recorder.  i have a few MTX mixes where i ran SBD > JB3 with a JB3 having major timing issues.  seems like when i run my newer tascam units in 24/48 or 24/96 the timing is much closer when i sync the files.  the JB3 only runs 16/44 and when i sync the files sometimes parts of the set will sync but others wont.  basically, if your ADC is problematic it might be very frustrating to mix the files no matter what you do.

[Walstib62]

Another trick in Audacity is to line up the beginning and cut both sources at track start. If you don't, the track you are changing will shift and you will have to realign the beginning every time.