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:
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.
the only thing i noticed wrong is the sound bug when loading from epsxe save states but using the epsxe core spu i don't have that problem, if you want more info i'll post SS of my exact configs for both plugins and epsxe