Noise Source

Noise Source. This module provides a number of noise types that, on their own range from low-frequency rumble (brown noise) to rushing air (blue noise). Combined with an envelope generator and filter, any number of drum sounds can be synthesised.
The Pink and Brown noises have a lower cut-off frequency of a few Hz, so they can also be used as an LFO source – the brown noise looks more like a slowly wandering voltage, with little content in the audio range.

440Hz Reference. A perfect addition to any synthesiser, enabling fast and accurate tuning of VCO's. Either mixing the VCO output with the 440Hz tone and tuning for no amplitude modulation, or clocking a sample & hold and tuning for zero-frequency, tuning can be trimmed even in a live situation.

When there is no jack inserted into the 440Hz socket the tone is disabled internally to ensure that it cannot interfere with the rest of the instrument.

Key Data

Module Depth:


Power Connector:

Doepfer 10-pin shrouded header

Current Consumption:

+12 Volts, 20mA
-12 Volts, 20mA

Reverse-Power Protection:


Panel Width:

4HP (20mm)

Panel Options:

White powder-coated aluminium.
Blue Noise
Blue noise power spectral density rises at 6dB/Octave, so is rich in high-frequency energy. Great for emulating cymbals.
Violet Noise
Violet noise power spectral density rises at 3dB/Octave so isn't so 'fizzy' as blue noise.
White Noise
The flat frequency response of white noise is perfect for filtering and effects.
Pink Noise
Pink noise
Brown Noise
The corner-frequency of the brown noise is below 20Hz, however the plot here looks flat. This is because the low-frequency response of the capture device is rolling-off at the noise profile continues to rise. The two cancel, giving the flat response.
440Hz Sine (Reference Tone)
The 440-Hz tone has a 3rd-harmonic 30dB down on the fundamental, which sounds pretty pure. It can easilly be used to tune a VCO, either using a beat-tone or lissajous figures on an oscilloscope.