Top Gear 2 sound issues without BLARG_APU

[m45t3r]

I was backporting the changes from #27 to my https://github.com/m45t3r/PocketSNES fork (here is the PR m45t3r/PocketSNES#3). And noticed that Top Gear 2 started to have audio issues.

First I thought that I had made some mistake during the backport process, but I resolved to test snes9x2005 on RetroArch with my PS Vita and sure it has the same issue (the build is quite old, from the start of this year I think, but since this change is from 2017 I should have it). So yeah, I think the issue is actually introduced by PR #27 (I did isolate the changes from this PR on my PocketSNES fork and the issue is reproducible).

What is the issue? Start a new game and on the first stage, right after the race starts you will listen an audio glitch. This audio glitch repeats every dozen seconds during the race, so it is pretty annoying. Comparing snes9x2005 with snes9x2005+ should make the issue clear (but there is also other sound issues from old snes9x APU that are not introduced in this PR) I think this is not the only game that has audio issues (I also noticed some changes in Final Fantasy VI, but I am not sure if they are closer to the original or not).

[m45t3r]

Just a update, the issue actually happens when you're trying to turn your car. Making multiple taps on left or right make the issue more clearly.