Colored Noise (sorry, I forgot to include the original post)

[Niklas Lindberg]

There are to "basic" types of noise, white and coloured.

The difference is that the white noise is unfiltered and the
coloured is filtered in some way. If i remember it right, the
coloured (pink) noise has a constant energy level at all frequencies
(which means decreasing amplitude for increasing freq.) and
the white noise has a constant amplitude at all frequencies.

The coloured noise is often called "pink" (for some reason i don't know)
and sometimes other colours are used (red, blue). I guess that
means it's filtered in some other way, to emphasize some part of
the frequency spectrum.

All types of noise are musically useful IMO, but for different uses...

For example:

LP-filtered coloured noise for thundering, earthquake-like sounds...

HP-filtered white noise for wind effects, sea sounds...

"Random" usually means randomly stepped voltage levels at regular intervals.
(the same as connecting a noise source to a Sample&Hold circuit clocked
by an oscillator). Normally this incorporates some sort of "Rate" control.

/Niklas
-------------------------------
Niklas.Lindberg at ees.enator.se


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>From owner-synth-diy at horus.sara.nl Wed Mar 13 19:18 MET 1996
Date: Wed, 13 Mar 1996 13:04:22 -0500
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From: Bob Zimmer <bzimmer at voicenet.com>
Subject: Colored Noise?
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In looking at various noise source schematics, it seems that White, Pink and
Random are the most common "colors" for noise sources.

There was a review of the Doepfler (sp?) modules floating 'round the net at
one time and their noise source includes knobs to blend the level of Red and
Blue noise.

Does anyone know of a source that would explain what these various color
types represent?

Are any of them (other than White, Pink and Random) musically useful???

  >=== Bob Zimmer -- Philadelphia PA ===<
  >=== bzimmer at voicenet.com          ===<




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