I'd bet it's the game's bug, not Dolphin's. Sonic Adventure DX was pretty poorly coded, AFAICT.
Have more evidence but first I upload the video :evil.
Salu2 - Darkness Knight
...That's how it fucking sounds on real hardware. Whatever bugs you're perceiving with this game in particular, check exactly how they sound on a real console before assuming that it's a Dolphin bug.
I don't see what you are talking about in the ice cap zone video, everything sounds normal. If you are talking about the collision detection at the end of the ramp, Sonic Adventure is known to have these issues on the actual gamecube. You can glitch through/bounce off walls all the time, the dreamcast version is even worse. I don't hear anything wrong in the chao scene either.
I can tell egg man's ship sounds wrong, though. I own both the DC and GC versions of the game, and I'm pretty sure the ship sound does not cut in and out like that. Try HLE audio instead.
I don't see what you are talking about in the ice cap zone video, it sounds normal. If you are talking about the collision detection at the end of the ramp, Sonic Adventure is known to have these issues on the actual gamecube. You can glitch through walls all the time, the dreamcast version is even worse. I don't hear anything wrong in the chao scene either.
I can tell egg man's ship sounds wrong, though. I own both the DC and GC versions of the game, and I'm pretty sure the ship sound does not cut in and out like that.
I can vouch for that, Melee has very obvious problems with the reverse engineered DSP Rom