From GameBrew - a wiki dedicated to Video Game Homebrew.
BlargSPC is a homebrew SPC player that is capable to play SNES SPC-dumped files on the 3DS. It is based on the SPC/DSP cores og blargSNES.
Q. Why am I getting this message: NDSP could not initialize?
BlargSPC uses the NDSP firmware for audio playback instead of the old CSND methods. This means you will either need to run a more recent version of *hax with relevant payloads (2.5 or greater) to have access to the hb:dsp service, or you need to dump the binary from an existing retail game or eShop title. The firmware is copyright data, so it cannot be supplied. If you wish to go with the dump method, then please go to the DSP Firmware Dumper page and follow the instructions.
Q. This can play SPC files of games that currently have no audio in blargSNES. Does that mean a fix for blargSNES is coming soon?
Unfortunately, no, not because of this anyways. The reason why blargSNES has trouble with some audio in games is because of communication/sync problems (among other things) between the main CPU and SPC cores. SPC files you may find online were dumped by other emulators that don't have this problem. But, at least this shows that the audio can process/play once this issue with blargSNES is resolved.
Q. Wait, I can play SPC files of games with enhancement chips in them. Does that mean...
No, it does not. The SPC/DSP cores are completely independant from the rest of the system with the exception of a couple of lines to the main CPU used for SPC uploading/downloading.
D-Pad - Navigate directories (Up/Down by individual, Left/Right by blocks)
X - Exit player
A - Play selected SPC file, Enter/exit directory
B - Stop playback
Some SPCs may not play, or may have clicks in them, but the majority of the files (tested by the developer) appeared to play fine.