Someone pointed me to Daniel Gattermann's blog post, which discusses a new and seemingly little-mentioned feature (there's almost nothing about it to be found via Google) on Intel-powered Macs running 10.4.8 -- ambient noise reduction.
You'll find this setting on your Intel Mac in the Sound System Preferences panel, and it looks like this:
Without this option the voice was clear but there was also a lot of noise from the MBPs fans and some static to hear. With this option enabled the sound seems to be a bit "softer" but more pleasant to listen to.It seems this is definitely Intel-only; it's nowhere to be seen on either my G5 or older 12" PowerBook G4. I haven't had the chance to test it yet myself (audio chats in the household are frowned upon during the early morning hours when I'm working on hints!), but will do so later today.
Mac OS X Hints
http://hints.macworld.com/article.php?story=20061113163546355