Do LASERs make a Sound? With A Photocell Light Theremin...Yes!

Tonight I dusted out the trusty old photocell oscillator (this one turns twenty next year) and decided that it was time to test it out with my newish laser projector, knowing full well that it would sound great!

I ran it through the Octatrack, with a channel running a comb filter and a little reverb, so it really gets some interesting resonance stuff going on. When the camera gets close to the unit, you can actually hear the raw tone coming from it's insides.

The sound of this single oscillator is pretty bland, limited to a knob for pitch adjustments, but there is a nifty trick inherent to the photocell, and how different wavelengths produce different timbres, so you basically have a built-in audio waveshaper under the hood! I learned of this early on when experimenting with a black light and noticed that it produced a much more intense and full sounding tone. Sunlight also produces a very pure and brilliant-sounding waveform.

Back when I was in college, I was taking a video technology course taught by the engineer of the Com department and we were learning about different light wavelengths and at the top was cosmic rays light, so I asked how I could get them for my theremin and I think he said that I'd have to get above the clouds so....I still don't know what THOSE sounds like! Sorry, I just had to include that anecdote.

These are actually a pretty simple build (or a cheap eBay purchase) for the adventurous!

Thanks for reading, I hope you liked my post!