Bit depth question

Hello,

Still fairly inexperienced with Audacity, but have questions about bit depth.

First: Running on Big Sur 11.2.1. Audacity version 2.4.2


I am doing some long-distance recording / sharing files with friends. We had been recording using 16-bit, but have recently started using 24-bit. We want to be able to share 24-bit files.


If I change the Audacity default to 24-bit, I am finding that when I import a 16-bit wav file to Audacity, it automatically converts to 24-bit. And if I import a 24-bit file, it converts it to 32-bit. (At least that’s what shows up in the track details on the left side.)

And, if the preferences in Audacity are set to a default of 32-bit, both 16-bit and 24-bit files are converted to 32-bit.

Is this how it should work? I believe this is a fairly new phenomena. I don’t recall 16-bit files being automatically converted in the past. Unfortunately, I’m not sure if this just started to show up after the last OS update… or earlier.



Thanks,
Mark

And, if the preferences in Audacity are set to a default of 32-bit, both 16-bit and 24-bit files are converted to 32-bit.

This is the normal default for internal processing. (The conversion to 32-bit and back is lossless.)

It’s actually more important that it’s 32-bit floating-point which essentially has no upper or lower limit (it can go over 0dB) and it’s just better & easier for digital signal processing. The most common example is if you apply some effect like EQ that pushes the peaks over 0dB. The waves won’t be clipped as long as you normalize or otherwise adjust the levels before exporting as 16 or 24-bit.

If you’re mixing that will also push-up the levels (mixing is done by summation). In that situation you can export as 32-bit floating-point WAV. Then re-import and normalize before exporting to your desired final-format.

Thank you for that. Yes, I “mostly” understand all that (and yep, I understand that it is 32-bit floating point). And that ideally we would just use 32-bit floating point format. We mostly just mix with Audacity.

The issue we have is that one of the guys we share files with is a complete computer-phobe… and won’t own one. He records on a Tascam and is limited to either 16 or 24-bit. We have to give him files on an SD card formatted for the Tascam. This hadn’t been a problem (other than the inconvenience), as Audacity wasn’t converting file formats. Now it is. My question was if this is what Audacity should be doing? And I guess… when did this change?

We can still do what we need to do… just a bit more inconvenient. We just need to make sure we do the things you mention, and be careful to make sure we export as 24-bit.

Thanks again for the feedback!

Mark

Audacity doesn’t keep track of the original format (except it will match the Project Rate/sample rate to the 1st file you open). So you have to choose the bit depth when you export no matter what.

It’s perfectly OK to share 24-bit files but you should let Audacity to work at 32-bits internally. And when you’re done there’s no good reason to distribute/shar your final production at 32-bits.

He records on a Tascam.

And, when the rest of you guys have “computer problems” he won’t! :smiley: :smiley: :smiley:

and is limited to either 16 or 24-bit

That’s OK too. And it’s OK to mix-and-match. Analog-to-digital converters (and digital-to-analog converters) are not floating-point so Audacity is up-sampling if you set it for 32-bit recording/processing. Your audio interface/soundcard determines the actual resolution and the drivers/software take care of any conversions (often without you knowing).

OK. Thanks! I was just getting confused over what seems to be a change in how Audacity deals with files when I import. I won’t worry about it… and let Audacity do it’s thing at 32-bits. And just make sure to export as 24-bit so we can share.

I guess a further question then is: The Tascam is also limited to 44.1KHz (or 48KHz) sample rate. When we import files to Audacity, the sample rate of the files show 44.1KHz (as recorded on the Tascam). I assume there is no advantage to setting the sample rate in Audacity to a higher rate? Correct?

Thanks again for the info. As I said we are new to this, and just trying to get a handle on how things work.

Mark

For normal audio work, correct.

Thanks!