[sdiy] Raspberry Pi 2 B Synthesizer Project Progress

[Scott Gravenhorst]

For those who might be interested in this...

I've developed what seems to be a stable 32 voice Karplus-Strong MIDI 
synthesizer and I've just measure the latency time (defined as from time 
of receipt of MIDI note-on to start of actual sound signal at the DAC). 
  This was done with a dsPIC and the measurement has a granularity of 
6.4 microseconds.  The latency I measured at first was 24.5 
milliseconds, but a bit of sleuthing and happy accidents in 
troubleshooting lead me to the source - ALSA buffer size.  Once I 
reduced it, I attained a measured worst case latency of approximately 
7.1 milliseconds.  This is with Xorg running...  I am currently stress 
testing it with Chopin Mazurkas and am finding no problems.

This has been quite a road of discovery...  I am motivated now to do 
more.  Next will be adding another synth (bitimbral) or an effects 
processor, perhaps both.  Seems the hardware ought to handle it.

This code is all in C.  I now have a framework of software for 
development of other synths.

-- Scott