I has seen the 10 year old VS1053b DSP chip mainly on boards that play mps and other steam formats. But the programmable DSP makes it versatile, it also can play MIDI files as well as playing real time MIDI.
Making the smallest possible player, perhaps in a fat MIDI plug keychain you could use as a last resort Casio class backup/test instrument, might be an interesting project.
I just recently ran across this thorough article on using the VS1053b in a real time MIDI player setup, operating in a standalone mode.
The Chip has built in:
128 Melodic Instruments (GM1)
87 Percussion Instruments (GM1+GM2)
And some up-loadable enhancements.
It’s maximum polyphony is 64, a maximum sustained polyphony is 40, depending on the instrument selection and DSP load from other processing options like reverb.
Boards using this chip often often have SD cards, one with a microprocessor might be able to use the OGG recording capability to archive a session using a built in mic. (A record to SD Card tutorial)
A Chinese board delivered in 5 weeks for $7.92 from Aliexpress, hobby shops like Adafruit and Sparkfun sell boards using this chip, for about 3X the Aliexpress price.
Briefly browsing the VLSI Solutions site in Finland, I noticed the VS1103, a simplified? chip that also does MIDI.
Guy playing some music on a generic MP3 board patched for MIDI
A run-through of all 128 presets (Can you guess the instruments)
I suddenly became interested in this chip after picking up a “Adafruit music maker feather shield” (51.0mm x 23.0mm) which includes a 3W amp, for 85% off in a local retail store clearance (packaging was becoming unreadable)
