AudioAdvContrl - Anyone know what these regestry edits do?

[SINC]

Hey guys i've always had problems hearing people on my TyTN from the ear piece.

I've discovered these regestrys in HKEY_CURRENT_USER and was wondering if altering any of these controls could improve my listening experience with the caller....

3D
AgcEnable
Bass
HpVol
ReceiverVol
RecLevel
SuperBass
ToneEnable
Treble

I'm going to try mucking about with it, but if anyone else can test these settings also... i'd be interested to know and compare results - especially someone else who is a little more technical than I am.

Cheers guys

SINC