Topic: a couple 24bit noob questions

[jagraham]

so i did my first 24bit show last night with ca11s>stc-9000>dr07@24/44.1.  i am very impressed with the dr07 compared to my old jb3.  anyway, i have figured out how to dither down but am still a little confused.  i understand the purpose of the 32bit float for higher quality editing.  now, i have isloated the 16bit and 24bit master files.  my concern is that the original recording from the dr07 sd card is a "32bit float" in audacity but was recorded at 24/44.1. why does audacity not recognize this as 24bit? is that something basic that i just missed?  my other problem is the file sizes.  the file off the recorder or the "32 bit float" that was recorded at 24 is 1.68GB for a 2 hour show while the 24 bit file from the audacity dither is only 1.12GB.  also, the windows explorer bitrate listing is 2116kbps on the master file, while the 24bit file says 1411kbps.  hope i havent made this too confusing.  one thing to note was that i had previously had audacity's preferences to 48000, not sure if changing it to 44100 made a difference.  anyway, hope someone can shed some light on this and ill post results later.

[page]

so i did my first 24bit show last night with ca11s>stc-9000>dr07@24/44.1.  i am very impressed with the dr07 compared to my old jb3.  anyway, i have figured out how to dither down but am still a little confused.  i understand the purpose of the 32bit float for higher quality editing.  now, i have isloated the 16bit and 24bit master files.  my concern is that the original recording from the dr07 sd card is a "32bit float" in audacity but was recorded at 24/44.1. why does audacity not recognize this as 24bit? is that something basic that i just missed?  my other problem is the file sizes.  the file off the recorder or the "32 bit float" that was recorded at 24 is 1.68GB for a 2 hour show while the 24 bit file from the audacity dither is only 1.12GB.  also, the windows explorer bitrate listing is 2116kbps on the master file, while the 24bit file says 1411kbps.  hope i havent made this too confusing.

It does recognize it as 24bit, but any adjustments you do will pull that section into the 32bit realm, thats what that setting is telling you. When you export files (or multiple files if you've tracked it out) then you select what to dither to during the save. 1411kbps is 16bit at 44.1, the other number (2116) doesn't look familiar, so I'm assuming it's a 24bit file at some sampling rate...

one thing to note was that i had previously had audacity's preferences to 48000, not sure if changing it to 44100 made a difference.  anyway, hope someone can shed some light on this and ill post results later.

Yes, changing that would affect things. Whatever you have project defaults set to, and then the sampling rate in the editor set to will be active when you export regardless of what the file was. So if you taped at 44.1, and left this setting at 48, when you exported with a dither to 16bit, even if you didn't run a resample routine on the file while editing, it will do it on export because you've specified 48... Not the most user intuitive setting I've seen.

[jagraham]

thanks for the help.  now i have another problem.  after dithering to 24 and 16 bit, i actually get the same size files for each.  i assume the 16bit sets are fine, but i am concerned about the 24bit.  the files are recognized as 24bit in audacity but are the same size as the 16 bits and are 1411kbps.

[notlance]

2116kbps = 24 bits * 44.1k samples/sec * 2

The factor of 2 is because it is a 2 channel file.

Try not to do sample rate conversions during editing.  You don't gain anything by converting from 44.1k to 48k, for example.  If you have to release a 48k version of your recording (because it will be used for a DVD soundtrack perhaps) you'd be better off recording the original at 48k.

And at the risk of starting a dither debate, don't sweat the dither.  For the vast majority of recordings the type of dither and even to dither or not just does not matter.  Most venues, even classical venues, are so noisy that the significance of dither literally falls down into that noise.

[jagraham]

thanks for the advice.  going 44.1>48k on my part was unintentional.  what was the potential for harm there?  i may have done it on past recordings, but never had a problem burning to cd later, so were the files actually 44.1 even though audacity formatted to 48?  as far as dithering, i really just need to know which set is 16 and which is 24 for distribution/burning.  any reason my file wont save to 24 correctly but will to 16?  it was mentioned in the dr07 thread that the unit may have issues doing 24bit, any info on that?  i really appreciate all the help from everybody.

[page]

thanks for the advice.  going 44.1>48k on my part was unintentional.  what was the potential for harm there?  i may have done it on past recordings, but never had a problem burning to cd later, so were the files actually 44.1 even though audacity formatted to 48?  as far as dithering, i really just need to know which set is 16 and which is 24 for distribution/burning.  any reason my file wont save to 24 correctly but will to 16?  it was mentioned in the dr07 thread that the unit may have issues doing 24bit, any info on that?  i really appreciate all the help from everybody.

I don't think your actually creating 24bit files out of Audacity. There is something you are not doing differently in the export and as a result, it's still going down to a 16bit level.

[jagraham]

just tried another conversion of file direct from the sd card > 24bit(32bit float>24bit) and the bitrate is stil 1411.  i have preferences > quality > Sample rate at 24bit/44.1 and the audacity window for the file says 24/44.1 as well.  im using audaity1.2.6 on windows vista.

[jagraham]

sounds right page, let me try r8brain from the masters and see what happens...

[page]

just tried another conversion of file direct from the sd card > 24bit(32bit float>24bit) and the bitrate is stil 1411.  i have preferences > quality > Sample rate at 24bit/44.1 and the audacity window for the file says 24/44.1 as well.  im using audaity1.2.6 on windows vista.

File > Export.

Attached are two images that describe what you should have for 16bit exporting for CDs and 24bit exporting. (shots taken on a mac, but I suspect it's the same thing).

Oh, and I recommend you use the latest Audacity 1.3.X. I disliked the 1.2.X tree for tracking.

[jagraham]

ok, got 1.3.11, looks nice but the only export option is 16bit, even though i have default rate in settings as 24.

[jagraham]

looks like i got it, had to go to "other uncompressed files" and go to options in the export window.  this really helped, glad i came on here to figure this out instead of figuring it out myself.  i got the 16bit files up on DIME already, hope those are OK.  ill get the 24 bit processed later.  doing any VA spring shows soon?

heres the shows...
http://www.dimeadozen.org/torrents-details.php?id=291171
http://www.dimeadozen.org/torrents-details.php?id=291170