A Look At The THX Deep Note

Some of us get really excited when we hear this sound. Others were scared of it as children. No matter how you feel about James A. Moorer’s THX “Deep Note”, you can’t deny that it’s one of the most unique sounds ever created.

But what makes it so special? Before we get into recreating it with a Teensy, we have to understand how the THX Deep Note is formed.

The Original Technology

The Deep Note was synthesized using a 20,000 line C program that Dr. Moorer wrote for the SoundDroid processor – which he also designed for Lucasfilm-THX.

The Swarm of Bees

The Deep Note is comprised of 30 different voices, each of which was a synthetic cello sound. All 30 voices are initialized at random frequencies between 200 Hz and 400Hz. This creates a droning, “swarm of bees” sound. From there, these voices’ frequencies are slightly lifted or lowered a few Hz.


When it comes time, these random voices go whizzing off to their destination frequencies – which aren’t a chord, but seem to be octaves of D/Eb. (It isn’t really either note, because Moorer detuned them all slightly so that they wouldn’t converge into a perfect octave and lose each voice’s definition.)

When the notes all head for their destination frequencies, they have a very special way of doing so. The path isn’t linear, or logarithmic, but happens in jumps. Take a look at the spectrograph of Deep Note below:


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