The Music of the Krell

Forbidden Planet is a movie from 1956. It featured a sound track and sound effects entirely created by electronic circuits. I say circuits because this was 8 years before Robert Moog would produce the first synthesizer. The sound track was produced by Bebe & Louis Barron using circuitas invented for the purpose and test equipment.

Watch the movie here: https://archive.org/details/ForbiddenPlanet1956_201707

I thought I should try my hand at recreating the music of the Krell with circuits I had made!

Krell 1

A good starting recipe is an oscillator, delay, and reverb. The Ugly Face (right) is an oscillator drive by a guitar input. When the threshold is turned up it will self oscillate. The out put is as square wave.

Krell 2

The Barron’s used ring modulation copiously in the Forbidden Planet sound track. I thought I’d get out yhe Zvex Ringtone. The Ringtone is sequencer and ring modulator. The Barron’s didn’t have access to a sequencer since it hadn’t been invented yet.

A ring modulator produces a signal that is the sum and difference of an input frequency and another frequency which is usually produced internally. The sequencer allows us to program the internal frequency in 8 steps. The input frequency comes from your instrument, in this case it’s the Ugly Face.

EX Mini Reverb
Ibanez Mini Analog Delay
Zvex Ringtone
Super-Freq Ugly Face

Krell 3

This time I used the Fuzz Factory as an oscillator. This pedal will oscillate on some settings usually when turn down the Stability and turn up the Drive, Comp, and Gate.

I also added the Zvex Seek Wah. This is a wah controlled via an 8 step sequencer. Imagine a wah pedal stepping through 8 different positions of the foot pedal.

Mosky Spring Reverb
Zvex Ringtone
Zvex Seek Wah
Fuzz Factory

Krell 4

This demo makes use of the Deadastronaut Tremshifter. The Tremshifter is both a tremolo and phase shifter in one box.

Krell 5

This demo uses the Commonsound.org Triwave Picogenerator as the sound source. This is a legend in the DIY realm. It’s has two oscillators, and three LFOs. You can mix the amount of LFO that influences the pitch of each of the oscillators. The LFOs also have a rate and shape control.