Getting into phase

Arguably the most problematic aspect of MAME’s PSX hardware emulation was the SPU audio chip. It had no envelope support, no reverb, and an assortment of bugs. Fortunately most arcade games use the SPU only for sound effects and have a separate chip for music so the problems weren’t as dire as a working MESS PSX driver might have shown, but glitches did occur and vex players (for instance, the siren in Tetris the Grand Master).

Anyway, pSXAuthor, the author of the pSX emulator gave us permission a while ago to use his SPU code in MAME. The problem at the time was that his code makes heavy use of C++ features and MAME back then was plain C only. Aaron’s recent architectural changes have finally made it possible to rock out with your polymorphic classes out in a sound chip emulation, and so I’ve finally done the port.

One thing the MESS driver does do is play .PSF music rips from PlayStation games. I’m going to use one of my favorite songs from one of my favorite PS1 games (Parasite Eve) here to demonstrate the before/after.

Current MAME SPU emulation
New pSX SPU emulation in MAME

I think you’ll find the improvement quite striking.




Source: rbelmont.mameworld.info