Events, Featured, Other, Sound
comments 10

The Evil Eye – Optical audio record by Indianen

evil eye 08 copy

The Evil Eye project is the result of a residency by Belgium collective Indianen at the Frans Masereel Center, a center for printmaking in Kasterlee. The project investigates how printmaking could produce another kind of information, transforming material into an object with a new meaning. 

When you put “optical audio record” on the record player it passes the handheld electronic “eye” the team has built: a simple device with an LED and a light sensor. The rotating patterns create modulating light that is translated into an electric signal by the eye. This signal is fed into a guitar amplifier and comes out as the exact sound that is embedded in the prints.

The app that generates the patters was made with Cocoa / Objective-C. It can create tracks with notes and sequences of notes with different waveforms like a synth, or just audio files (.wav) that you load into it. The screenshot below shows the record in the making and allows user to move and scale the tracks, change the sample rate, etc.

The track editing view superimposes waves on top of each other and allows for adding tones, moving them around and changing their pitch and waveforms (square wave, sine, sawtooth, etc…). The software finally exports the PDF files (single track image on the left which includes only sine waves or many different tracks, mostly square waves, on the right – the label was added in illustrator afterwards )

 The device used to read the patters contains a small electronic circuit that converts the light it receives into an audio signal. When you hold it above a spinning (optical) record, the LED at the bottom shines on the pattern (see video below). The light that is reflected from the paper is measured by an optical sensor and that’s the signal that gets sent to the amplifier. There is no extra processing of the signal.

Evil Eye performance is taking place on Thursday June 28th 2012 at the Frans Masereel Center, Kasterlee, Belgium.

IndianenFrans Masereel Center.

  • Gavin

    Instead of an “optical synth”, why not use the iPhone flash for the light and the camera as the sensor? Bet it would work the exact same way and remove the need for specialist hardware….

  • Andrew Shooner

    Well, that wouldn’t get anyone to show up at the Masereel Centre.

  • Tim

    Hi Gavin, this it tim, I built the hardware.
    We also thought about your suggestion, but our solution is actually quite simple, much less complicated than creating an app for iPhone. We use a simple light-to-voltage converter that doesn’t do any processing. An iphone app would require some visual processing but more importantly also some kind of synthesizer. (I think) In the setup we used, all the sound is encoded in the disks and there is no need for anything digital.
    Also, we like the idea that people can play the records only once and then have the information locked in the printed disks forever :-)

  • Check out the work of Dutch artist Mariska de Groot Its about just this.

  • Nice work! I put on a conference/festival last year on work like this (we called it ‘direct sound’) going right back to the 20s –

  • not as good as “soundmachines” from “the product”

  • tim

    I used to work with patrick and dennis from the product. Amazing guys and great work!

  • Gavin

    thanks for the explaination :)

  • Jefe aka Johnny Chiba
  • NIce! Is there any footage of the performance?