Shinzon: I know this workarround is for Star Wars EP1 Racer, but it is the same problem, at least for me.
Shinzon, thank you so much for posting this fix over here - it works for me too :) I did some investigation on the device using pcilookup.com - although I can't find an exact match with both Vendor ID and Device ID, searching with just the Vendor ID turned up two device entires. One was from NKK Corp. - probably not relevant - but the other Vendor was Turtle Beach, and my headset is TB. Interestingly, the headset still seems to work with the device disabled - and sure enough, Myst IV launches every single time while it's disabled.
A full explanation still doesn't spring to mind - but perhaps the game is still dependent on an ancient version of OpenAL or DirectX, from a time before HID-driven audio devices existed.
Anyhow... for anyone who's curious but isn't sure how to identify these "almost anonymous" HID devices...
1. Open up Device Manager
2. Expand "Human Interface Devices"
3. Find several named "HID-compliant vendor-defined device"
4. Right-click and choose Properties
5. On the Details tab, select Hardware IDs in the dropdown
6. Note Vendor ID and Device ID (details below)
7. Visit pcilookup.com
For Vendor ID and Device ID, check the first line returned in the details. Mine looks like this:
HID\VID_10F5&PID_2154&REV_0100&MI_03&Col02
Vendor ID: 10F5 (code after VID_)
Device ID: 2154 (code after PID_)
If you see no results entering both into the PCI lookup page, try searching on just Vendor ID. This should at least return devices from a company you recognise as providing one of your own, as with Turtle Beach for me. This won't help much, aside from satisfying curiosity, and perhaps letting you know what you might lose with the device disabled.
I haven't been past the title screen just for testing - the video looks a bit rough, but we'll see how I get on with that. Thanks again Shinzon, for passing that fix over here!