[sdiy] Various colors of noise.

[Thomas Hudson]

Yes very much different. There’s an old article in Scientific American by Marvin Gardner, that shows that music statically follows 1/f  or pink noise.

Note selection by red or brown noise is very boring. Imagine you have a random set of five dice to select the next note. Red / brown is only rolling  one of the dice for every selection.

Random sampled noise at any specific color frequency still follows the statistical likelihood of the next sample for that color..

There’s great way to hear the difference:

-  Colored noise, clocked sample / hold, quantizer, note selection.

The note selection differences are very apparent.

Though it would be interesting to plot the curves at various sample rates.

 

> On Mar 2, 2026, at 8:31 PM, Emily Straight <emily.tw.straight at gmail.com> wrote:
> 
> is there any statistical difference between different colors of noise after going through a sample-and-hold? i'd figured on longer timescales every possible voltage is equally likely anyway, so you wouldn't be able to tell the difference.
> 
> On Mon, Mar 2, 2026, 3:26 PM Thomas Hudson via Synth-diy <synth-diy at synth-diy.org <mailto:synth-diy at synth-diy.org>> wrote:
>> I have an analog module that can generate blue, white, pink, and red (brownian) noise. I’m interested in how I might create a random walk using perhaps a sample/hold and smoothing function to produce a sort of wandering control voltage from each of these noise sources.
>> 
>> I also was recently introduced to green noise. From Wikipedia:
>> 
>> The mid-frequency component of white noise, used in halftone <https://en.wikipedia.org/wiki/Halftone>dithering <https://en.wikipedia.org/wiki/Dithering>[19] <https://en.wikipedia.org/wiki/Blue_noise#cite_note-19>
>> Bounded Brownian noise
>> Vocal spectrum noise used for testing audio circuits[20] <https://en.wikipedia.org/wiki/Blue_noise#cite_note-comp.dsp_FAQ-20>
>> Joseph S. Wisniewski writes that "green noise" is marketed by producers of ambient sound effects recordings as "the background noise of the world". It simulates the spectra of natural settings, without human-made noise. It is similar to pink noise, but has more energy in the area of 500 Hz.
>> 
>> Wondering how I might generate this other than using something like a bandpass filter tuned to 500 Hz using pink noise. I want to generate it in the analog realm.
>> 
>> TIA,
>> Thomas
>> 
>> 
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