The same problem appears on Langrisser IV for the PSX as well... and it appears that it has something to do with the BIOS... will do more testing and see what happens. I managed to get it working on PSXeven 0.19 with some tweaking. My configuration:
PSXeven 0.19
SCPH1001 BIOS
CDRXeven
PEOPS DSound Driver 1.9
PEOPS Soft Driver 1.16
All on default settings.
Or it could be that it's a problem with the CD itself, the images I have may be bad, as the sound emulation is unusually screwy.
Well, for whatever reason, Xeven's sound emulation is slow. Dunno why though.
Edit: Alright, well, I've finished my testing. The game works fine with Xeven's emu (but I haven't found a way to get it to work with ePSXe 1.6.0, I believe it's probably a coding bug), so I'll just leave it at that. His sound emulation is still slow, but I'm sure in a year or so it'll be up there with ePSXe, or at least I hope.