OK... so if your reading this your probably in the same boat as as many people, everthing works great but..... no sound. After countless tries with many different ideas from many sources I've made a compromise. I've given up on support for my onboard Azalia Intel Audio and opted for USB sound. I installed the Soundblaster USB audio kext from the JaS 10.4.7 dvd and ever single usb audio device I have plugged in so far has worked great ( example 2 different C-Media usb audio sticks, Logitech USB headphones, input and output work, generic mic, and web cam mic ) Give your brain a rest and stick with USB audio... no hasel and it works.

FYI

Acer 1642 Laptop
JaS 10.4.7
usb
dvd burning
QE , CI
Power Management

All working great

Good Luck...Robert