Electromagnetic Swan Song of a Power Cord

The great thing about sound design is that broken stuff suddenly becomes usable and beautiful in its own right. The other day, the charger of my laptop broke — it just wouldn’t charge anymore and emitted a weird buzzing sound. So naturally I got out my telephone pickup coil and attached it to the charger. Turns out the buzzing was a little swan song:

Rest in peace, little overpriced piece of technology.

For those interested in the tech behind it, a telephone pickup consists of a coil that can “sense” electromagnetic fields: a nearby changing magnetic field will create current in the coil (if it is part of a closed loop) through a process called electromagnetic induction. As such, telephone pickups work differently from regular microphones: while microphones convert acoustic energy (pressure changes in the air) to an electrical signal, coil pickups convert the energy of a magnetic field to an electrical signal. Since any electronic device will create an electromagnetic field proportional to the current flowing through it, you can stick a telephone pickup on any electronic gadget to explore its hidden electromagnetic world. The resulting sounds are a great source for any type of glitchy, techy or digital-sounding sound design. I’ve used coil recordings in the past to simulate the sound of weird static, transmission issues and glitches.

I use the cheapo Radioshack telephone pickup coils that look like this:

Telephone Coil Pickup

You can find them on Amazon. Jez Riley French also sells some modified ones on his website.