RPi Turbo Update

In my previous post, I reported my investigation on building a synth on the RPi and although for the price it was amazing, the performance didn’t go near what the priciest Beagleboard could deliver. However today got anounced a ‘Turbo mode’ update for RPi that, amongst other things, allows automatic overclocking and better handling of Audio/USB. And boy they didn’t lie !

1. Built-in Audio:


  •  512 samples – 4 voices
  • 256 samples – 2 voices


  • 512 samples – 11 voices
  • 256 sampes – 7 voices

The default device still won’t go under 256 for the buffer samples but what a difference. The audio is still a little garbagy (due to it’s architecture) but becomes totally usable.

2. USB Audio:


  • 512 samples – 5 voices
  • 256 samples – 4 voices
  • 128 samples – 2 voices
  • 64 samples – 1 voice


  • 512 samples – 12 voices
  • 256 samples – 8 voices
  • 128 samples – 5 voices
  • 64 samples – 3 voice
  • 45 samples – 1 voice


  1. Thank you for the link. Unfortunately I can’t figure out how to execute the program. I made it executable with chmod, but my Pi wants me to choose a program to open it with. Do you know what I’m doing wrong? thanks!

    1. just start it from the console just after booting. i.e. don’t do that startx.

      simple type

      ./lgpt.rpi-exe and it should start

      if the screen you use is too big, you can scale the display by doing

      ./lgpt.rpi-exe -SCREENMULT=2

      to make it twice as big.

    1. No one ever said audio buffer size had to be powers of two :)

      It is usual to use so because it makes it easy to be displayed in a drop down box but it is no way needed hardware wise.


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