Loobyluggs:

I have switched my soundcard to 16 bit, 24 bit and 32 bit and (using a variety of music CD's and applications) I can tell the difference - the best way to describe it is 'warmth' or perhaps, 'breadth'.

If you're hearing a difference in music CDs, I'm 99% sure whatever you're using to change the bit rate is also tweaking the equalizer without telling you. All music CDs are 16-bit with a 44.1KHz sample rate. Like I said before - you can't re-create lost data. Think of it like editing a video: if you take a 640p video and scale it up to 1080p, you're not going to see more details; you're just stretching out the few pixels you started out with. You can smooth out the pixels so it looks less "blocky", you can do some post-processing to reduce noise or increase sharpness, and you can tweak the color profile (which I guess is analogous to an equalizer), but you won't get more details than what you started out with. So - your sound card drivers are most likely artificially tweaking the source to sound "warmer" as you adjust the bit depth. You can try to experiment with this: Uninstall all of the software your sound card came with. Let Windows install just the barebone drivers. Using the Windows control panel, turn off the equalizer and try the different variations of bit depth and sample rate. I guarantee you will not hear any difference in your music CDs, provided you don't go any lower than 16-bit @ 44.1KHz.