Well..PPSSPP has that issue for Dangan Ronpa ._.
It's just like me before :3
By the way have you try this? :
PPSSPP Method:
1) Download modified PPSSPP build at http://buildbot.orhpis.net/ppsspp
2) Run PPSSPP, settings, audio and download the atrac+ plugin. make sure its enabled.
3) Exit PPSSPP, open the newly generated ppsspp.ini file
4) Ctrl+F Framebuffer
4.1) Set FramebuffersToMem = "False" to "true"
4.2) Set FramebuffersCPUConvert = "False" to "true"
5) Save