GBA Audio: PSG sound channel 3 sounds different than on actual hardware in Battle Chip Gate Homebrew

[StraDaMa]

I'm not sure how different the other PSG channels are, or if other games are affected. But the example I have is for PSG channel 3 of the start jingle in Battle Chip Gate Homebrew. I've recorded just PSG channel 3 of the start jungle on a real DS lite (using an aux cable), VBA, and mGBA 0.11-8127-17a549baf. The VBA and DS recordings are the most similar, while the mGBA one sounds off. I can't record a real GBA without the recording being super noisy, but it sounds like the DS one.

To reproduce this:

1. Run the included homebrew that's been modified to only play PSG channel 3 of the start jingle.
2. Pick any game
3. Press Select to skip the "waiting for a connection" check
   mgba_psg3_issue.zip