One thing to note about spu pluggins that have the spu irq options is to not enable spu irq in both the pluggin options and epsxe sound options.. Enable spu irq in only the espxe sound options or only in the pluggin config options.. Not in both places as it has been known to cause problems with sounds.. The rest of the options in the pluggins you can read from the readme's that come with them.. I turn everything on except for a few options in iori's pluggin.. Disable real time config, unless you are playing in windowed mode.. I use Andy's spu for Vagrant Story..