Cobalt wrote:So I've heard that when you're bouncing an unmastered song it's best to bounce at the same bit depth you're working in
You're not necessarily "working in" a certain bit rate. Instead, the audio files used by your project each have their own bit rates. The bit rates can be the same for all your audio files - but then again they could be different ones. You could use 16 bit samples but 24 bit audio files. Or the opposite. Or some 16 bit and some 24 bit audio files. Logic's audio engine is processing everything at 32 bit floating point, independently of the original format of the audio files. Logic does not allow you to bounce 32 bit floating point audio files, which would be unnecessary for that application anyway as long as you are using "reasonable" digital audio levels (meaning you're not bouncing your project at -55 dBFS for example).
Assuming you only worked with 16 bit audio files, you'd still want to bounce a 24 bit file.
So in conclusion I would always bounce a 24 bit audio file if I want the best quality possible.
Cobalt wrote:and save the dithering process (i.e. 24 bit to 16 bit) til the end of mastering so you only do it once.
Dithering should occur when converting from 24 bit to 16 bit. And that conversion should be the last thing you do at the end of the mastering process - but if you did that conversion before, then dithering also should occur before (although I can't think of any situation when you'd want to convert to 16 bit before the end of the mastering process).
Cobalt wrote:What's confusing me is I'm not sure what bit depth I'm working at, as my song is mostly Logic's virtual instruments.
Logic's virtual instruments all generate 32 bit floating point signal.
Cobalt wrote:There are also a few audio files in there, some 16 bit, some 24 bit. I looked in the preferences and project settings, but only found a "24 bit recording" option.
That option determines what bit depth will be used for any new recordings you make - it does not affect anything that is already recorded.
Cobalt wrote:What bit depth is my song file playing at by default?
32 bit floating point.
Cobalt wrote:Should I bounce my unmastered files in 24 bit or 16 bit if they're mostly VIs? Or does bit depth not apply to VIs
VIs or not you should always bounce unmastered files in 24 bit.