Reflective Photophone: A New Type of Audio Transducer

Описание: I’m developing a new tool for sound designers. Is its sound quality good enough? You may judge.

The reflective photophone is an audio transducer that works using light. Its neither a microphone nor a hydrophone, so it doesn’t sense fluctuations in pressure. You could think of it as an optical contact microphone.

This video presents a catalogue of sounds I captured with a stereo photophone prototype in 2024. It picked up interesting audio from some ordinary things that don’t make much sound on their own. I noticed it has a way of creating sonic illusions of large size from small subjects. And I found I could use perforated optical masks as a modulation effect. Surprisingly, it picks up strong audio from ripples on the surface of water.

There are several positive aspects that set the photophone apart from microphones: Full rejection of off-axis sound and background noises. Flat frequency response across the audible band. Absence of sound coloration due to phase interference. No proximity effect. No microphone handling noise. No mass loading of the subject as with a conventional contact mic.

Having said all that, it probably won't be the best choice for recording rock bands!

This is different than the Lite2Sound devices I also make. Lite2Sound is designed to hear ambient light. Quite opposite, the device in this video ignores ambient light. So substituting a Lite2Sound device in place of the photophone this video would not give the same results.

-- Video timeline --
Music box 1:37
Ruler 3:19
Tuning forks 4:47
Gold leaf 7:15
Seedheads 9:21
Heat sink 11:22
Slinky 12:26
Ball Bearings 16:08
Eraser template 20:06
Water jug 20:44
Water syringe 23:04
Isopropanol + Water 25:32
Acid + Bicarbonate 27:01
Tuning forks and water 29:01

Audio recording detail for this video: Stereo 3.5mm analog output from the photophone was patched to an Allen&Heath WZ analog mixer, digitized with E-Mu 1616m 24-bit audio interface, and recorded in Sony Vegas. No EQ or de-noising plugins were used. Track Compressor plugin was used in some sections.

Developed by Eric Archer / Rare Waves LLC (USA). Copyright 2024 CC BY-NC-ND

If you’d like to be notified by email of upcoming product announcements, get in touch through rarewaves.net … Thanks for watching!