Yes, to install the Transit software was once (not too long ago) posted by a user here as a working remedy for the OS9 soundmanager failure on a Mini G4.
It may not work in every case, as XR-Lane just wrote. Sad, but guessing from my own experience with OS9 sound (before I had a Transit interface) not that surprising either.
I got it kind of working (using an external line amplifier) but results flipped from great to plain failure in a very unpredictable way.
Sidenote: I'm not interested in any system/entertainment/multi-media sound and didn't spend a single minute on such topics.
Bias Peak, SonicWorx, Tokyo and similiar apps are my only interest in OS9 audio.
@XR-Lane I didn't want you to read even more pages - that was kind of a joke
I assumed you may gave missed some points (possibly mentioned in other threads).
The Mini G4 was never intended to run OS9 software. Never.
That smart folks of this board got it running is one of the greatest hacks ever, but it remains... a hack.
To have OS9 boot at all, the soundmanager needs (at least) a dummy device to not break the startup process. It was clear that this fake woudn't work, but a possible fix might be applied later.
It's not a simple fix because hardware isn't documented and one would have to reverse engineer the software from OSX test results.
I never measured the G4 specs, but onboard audio from that time NEVER was great.
(it's probably similiar to those current $10 USB audio devices mentioned earlier)
There's a wide variety of audio interfaces (2nd hand) with OS9 drivers, up to Tascam FW mixers featuring motor faders for $200.
ALL these devices perform much better than the built in G4 audio hardware and for that reason it's a waste of time to rebuild the missing OS9 part.