Немного новой информации от ffgriever
Unfortunately, the new SPU emulation isn't that good as I thought it was. In some games it works almost perfect, while in others it's still a crap. The main problem right now is that it's software spu, so it requires a lot of cpu resources to emulate the sound (depends on number of voices that are playing and speed of the game... the slower the game works, the more sound it has to process, and the processing takes more time, thus slowing the game further, making even more sound processing to be necessary - but at least it scales quite fluent to the framerate). It has one advantage though. The sound is fine at both very fast and very slow fps (and perfect at exact 100% rate). The previous (hardware one, the PSX's SPU and PS2's SPU2 are very, very similar, almost the same), worked good only when the fps was exactly at 100%. If it was too fast, the sound has been becoming a cacophony, when too slow, there was a lot of stuttering, clicks and weird sounds.
I think the hardware sound emulation (more like translation) is the one I'm going to concentrate on in the future, as it almost doesn't decrease framerate at all... But right now I don't know how to properly handle cases when a game works too slow (the sound really hurts my ears )... When it's too fast, it's not a problem (frame limiter, though even now, when the limiting is not perfect, some clicks happen).
Yet I'll publish my current build anyway (both versions with sound and without sound - something like "null plugin" on pc emulators... here the plugin can be changed only at compile time ).