Hi everyone,
I just wrote a small utility to help figure out sound issues on (previously) unsupported Macs. It tells you what sound output drivers are currently active.
Here is the output on a Mac Mini.
SndDevSearch 1.1 starting up
1 sound output device detected
sdev #1
SubType 'awgc' Manufacturer 'appl' flags 0x8000000c name 'Built-in'
0 audio components detected
This is enough information to find the driver code in the System File, given knowledge on the Sound Manager and Component Manager (hint: look for a 'thng' resource which contains the strings 'sdev', 'awgc', and 'appl').
Here is the utility. May it be useful.