LLE is still in development. Use HLE for sound. Either way, the music in Melee is known to be broken and has been that way since the very beginning. Chances of it being fixed soon are slim. Using LLE MIGHT also be the cause for the tremendously slow speed.
Be sure to have Dual Core, JIT Dynarec, Optimize Quantizers and Idle Skip enabled, as those provide the most speed.
As for the black screen, I'm not sure. Try deleting the ini file from the Config folder in the "User" folder. That truly reverts most of the changes back to default.
__________________
AMD Athlon 64 x2 5600+ ~2.9 GHz
XFX GeForce 9800 GTX+ 512 MBs
2 GB DDR2 ~800 MHz