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Electronic Theatre Controls Inc

Sound2Light Frequency Bands


The Sound2Light processor drives the first six playback faders according to the frequencies contained in the sound. Low, bass, frequencies go to Playback #1, higher to #2 and so on to #5 driven by high treble sounds.

The frequency range is divided into five bands as follows:
Playback 1: 15-100Hz
Playback 2: 100-360Hz
Playback 3: 360-1296Hz
Playback 4: 1296-4665Hz
Playback 5: 4665-22050Hz

When there is no sound Playback 6 is activated as a rest or silent background state.
The rest state is driven after a delay so that it only appears when a sound clip has finished.

Additional Information

The slope is 24db per octave
There is also a fixed high pass rumble filter at 15Hz 24db/octave.
Audio is detected by an envelope follower with a time constant of 100ms for AGC (automatic gain control) and 5s for activating a lighting state.

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