Awesome Oscillographic Synthesizer, de/Rastra, Made From Old TV

Here’s another cool project from Kyle Evans, creator of the electroacoustic didgeridoo.

The de/Rastra oscillographic synthesizer is a real-time audio/video instrument and computer-interfacing device that lets you generate visualizations intrinsic to cathode ray tube technology while simultaneously creating the acoustic analog of the displayed imagery.

Here’s what Evans has to say about the de/Rastra oscillographic synthesizer:

Through hacking and exploiting the capabilities intrinsic to all CRT devices, the technology becomes repurposed as a performative interface, breaking down the device’s ‘consumption only’ nature. The performer is given control over the technology by removing it from the intended application and forcing it into an active state through a combination of physical and mental effort.

Technical details:

  • Computer interfacing:
    • Atmel 328 communicates with a program designed in Max/MSP via xBee wireless communication.
    • 4 Force sensing resistors: generate sounds and visuals by varying the amount of pressure applied to them.
    • 3 axis accelerometer: modulates signals as the instrument is moved through space.
    • 4 momentary push button switches: Generates sonic and visual accents and quick events.
    • 6 flip switches: Used to change between the different program states throughout the performance.
  • Visualizations:
    • Multiple audio signals created by the Max/MSP patch are amplified by a 4 channel 400W power amplifier and inserted into the CRT’s yoke (X and Y deflection axes controlled by different signals). This deflects the electron beam in a fashion that is directly connected to the audio being produced.
    • Additionally, an electromagnet inside the CRT, also being driven by an audible sine wave, deflects the beam further creating the colorization.

The de/Rastra oscillographic synthesizer is an open source project and will eventually be accompanied by tutorials on methods of CRT hacking. You can find out more about Evan’s oscillographic synthesizer project at the yaktronix site.

3 thoughts on “Awesome Oscillographic Synthesizer, de/Rastra, Made From Old TV

  1. I love good examples of sound and image in perfect harmony. The synchronicity of the waveforms displayed and heard is uncanny. I think this is really well executed.

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