pisound by blokas Blokas

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pisound is an ultra-low latency high-quality sound card and MIDI interface for Raspberry Pi ® pocket computer. This little board will bring your audio projects to a whole new level!

Technical Specs

We used the legendary Burr-Brown Op-Amps, ADC and DAC chips in this little board to ensure flawless signal amplification and conversion. Of course, everything is hooked to the dedicated ultra-low noise power supply in order to get maximum signal fidelity and minimum interference.

Furthermore, unlike usual MIDI solutions for Raspberry Pi ®, MIDI on pisound is implemented using high speed SPI and a dedicated MCU for translating SPI data to serial MIDI byte streams and it's readily recognized in audio software as an ALSA Raw MIDI device.

Stereo Input:
  • Input sensitivity at 0dB gain: 5Vpp
  • Max gain: +46dB
  • 24-bit ADC
  • Sample rates: 48kHz, 96kHz, 192kHz
  • Physical Gain control
  • Clip indicator (LED)
  • ¼" 6.35mm Stereo socket
Stereo Output:
  • 24-bit DAC
  • Sample rates: 48kHz, 96kHz, 192kHz
  • Output level: 2.1 VRMS at 1 kΩ load
  • Physical Volume control
  • ¼" 6.35mm Stereo socket
Audio loopback:
  • SNR (at 1kHz): 110 dB
  • Bandwidth (at 48 kHz sample rate): 7.5 Hz – 23 kHz
  • THD: less than 0.05%
  • Latency: 5ms
MIDI loopback:
  • Latency: less than 1.3ms
  • Power Supply: 7.2 - 12.6VDC, 20W - Provides power to Raspberry Pi ®
  • PCB Dimensions: 100mm x 56mm

Pin Map:

Connecting to Raspberry Pi ®

pisound connects directly to the Raspberry Pi ®, no additional cables or soldering required. Just plug it onto your Raspberry Pi ® and use included M2.5 spacers to fasten it.

PureData and pisound

You can run your PureData patches straight from a USB thumb drive with a press of a button with no need to connect an external monitor, keyboard or mice.

Plug in a USB drive containing your PureData main patch file called "main.pd", plug in any additional MIDI controller/keyboard, press The Button and Voilà!

You can install PureData by running the following command in a Terminal window:

sudo apt-get install puredata

Installing Drivers on Raspbian OS

Run the following commands one by one in a Terminal window:

wget http://blokas.io/pisound/install-pisound.sh
chmod +x install-pisound.sh

Restart the Raspberry Pi ® by running:

sudo reboot

After restart is complete, in order to verify successful installation, look for pisound being detected by the following ALSA utilities:

aplay -l
arecord -l
amidi -l

You can find the pisound's source code here: GitHub/BlokasLabs/pisound