Explore the sounds of modulated light!

Sound is encoded in the ambient light around us, yet few people have heard it.  Modulated light can sound like noise, harmonic tones, or even rhythms and music, depending on where you look.  Ambient listening with a photodiode amplifier is sort of like hearing a radio station that plays serendipitous music, a personal soundscape that you guide by moving and pointing your receiver in different directions. 

Modern technology is a fascinating source of modulated light, especially in the city at night.  Riding in a car or train, listening through the window to the busy nighttime cityscape, one hears an ever-changing and sometimes startling sonic picture of the world.  Inside or outdoors, there are many rewards for the curious listener with an ear for the unusual.

Field recording in the city at night with a photodiode amplifier

To hear modulated light, you can use a photodiode amplifier like Lite2Sound™ from Rare Waves.  It is a simple but clever device that combines a light sensor and an audio amplifier with headphone jack. 

How does light relate to sound?  When a light source is flickering rapidly, we can’t see it changing because the frequency is too high.  But, our ears are very sensitive to these frequencies, if we have a way to convert changes in light’s intensity into sound.  That’s what a photodiode amplifier does – it converts changes in light intensity into an analog voltage. Then an amplifier uses that voltage to move your headphones or speakers so you can listen. 

A photodiode amplifier is unlike an oscillator or synthesizer, because there is no indirect “mapping” involved.  Instead, it is more like a microphone that directly reveals a hidden layer of reality.

On this website you can find free plans to build your own light-to-audio converter, and a source for photodiode amplifier DIY kits and fully assembled models.  Our Lite2Sound circuits are being used by sound designers, field recordists, paranormal investigators, and ambient music enthusiasts.

If you are a DIY workshop instructor, we would be pleased to work with you to offer Lite2Sound as a class project at your studio.

Lite2Sound™ is a trademark of Rare Waves®. Rare Waves is an American manufacturer of analog synthesizers and electronic music equipment for creative musicians, producers, and sound designers.

This website is created and maintained by Eric Archer.

The information on this website, including schematics, text, and graphics, is published under Creative Commons CC-BY-NC license.  Authorization is granted for non-commercial use only, provided that attribution is given to the original author Eric Archer (Rare Waves LLC).