Friday, October 15, 2010

Analog Noise vs. Digital Noise

My Doepfer A-100 system includes 2 Noise different generators, the A-118 Noise/Random Voltage Generator, and the A-117 Digital Noise Generator.

A noise generator is an oscillator that produces an internal noise signal, typically white or pink noise.
Noise Generators produce random signals, containing harmonics on all frequencies, and can be modified into the desired tone. 

The A-118 produces white and colored noise. The white noise is the well-known 'hiss'.
The spectrum for the white noise has the same amount of energy in every section. 
The colored noise output of the module is a mix of blue noise ( high frequency component ) and red noise ( low frequency component )

Noise in the audio spectrum can be used in many ways, most commonly in wind-effects, or in cymbal crashes and hi-hat -sounds.

The A-117 Digital Noise sounds very different and has less control possibillities.
This module has 2 outputs, consisting of mixes of multiple oscillators to re-create vintage Roland TR-808 and TR-606 sounds like the hi-hat, cymbals and cowbell.
One output has a mix of 2 fixed digital oscillators, that can be used as a basis for the distinctive 808 cowbell-sound, the outher output has 6 oscillators to form cymbal and hi-hat sounds.

The Random outputs of both modules can be used as a Control Voltage for all kinds of stuff. I prefer the Analog Noise for that, simply because it has more controllers.
I often use it as a modulation source to add subtle changes in a filter (check out a short example HERE), but these modules can also provide interesing effects in combination with the A-148 Sample and Hold module. More on that in a later post...

Video: A-118 Demo 

A118 Noise and Random voltage generator demo made by @Hawklord2112