just use the internal spu it should work or if you have vgs play it there its not too bad on vgs since its only 2d except if your using petes software gpu its really good looking in this plugin compared to petesogl or d3d
I would reccommend giving Iori's SPU vers. 1.46 a try w/this game. I use it with Castlevania SOTN and I get full music, speech, and everything else. Give it a try and see what you think.
Just in case we've missed the obvious don't forget to check that xa audio is turned on under the sound options. Epsxe turns is off by default on first installation. BTW Castlevania uses a specific resolution so unless you're using Kazzuya plugin or have turned on the keep aspect ratio on Pete's plugin the graphics are goin to look slightly stretched. The original resolution is 256X240 so if you're using one of Pete's Accelerated plugins set it to window mode and make the resolution 512x480 or 768x620 depending on your desktop resolution. Beware the time runs too fast under Epsxe so you only have 9 hours to complete the game.