Good news.
Music and Sound should now play fine. I observed problems with pitch changed (speed up/down) music but otherwise it works quite fine. Sound effects will hang the first time they are played because they are cached, afterwards it’s lagfree (same strategy as the Wii version, just with more lag because 3DS is slow).
I also noticed that the performance got worse in general but this in unrelated to the audio code and must be something else… (but is still on a playable level on old 3ds in my opinion)
Furthermore the heap size got adjusted, games should run much later out of memory now.
The code is not yet in our repo, so here are the downloads:
https://easyrpg.org/downloads/tmp/easyrpg-player-latest.cia
https://easyrpg.org/downloads/tmp/easyrpg-player-3ds-latest.zip
Note about MIDI: I added the midi instruments to the romfs but I still have no a9lh, so can’t test the CIA ;). If MIDI does NOT work you have to take the wildmidi.cfg and instruments folder from the zip and place the files in /easyrpg-player/wildmidi/ on your SD card.