I'm working on a reimplementation of the Sound Driver API via the Sound Manager, called Legacynth.

A number of old games that use the Sound Driver are still able to run in Mac OS 9, but with no sound — there's a .Sound driver on PPC and AV Macs, but it doesn't produce audio. Legacynth intercepts the I/O calls to the driver and translates them into Sound Manager calls. The initial release supports sampled sounds and comes with a test program so you can easily verify that it works.

You can download it here: https://www.macrelics.com/legacynth/

There's also AGPL-licensed source code in https://github.com/jjuran/metamage_1 under apps/mac/Legacynth/.

The next release (with square-wave tones) is coming soon, but in the meantime, I'm interested in any and all feedback. Beyond making it work, I put some real effort into making it usable, and I hope it shows.