[sdiy] Akai S612 filter/schematics

[Magnus Danielson]

From: Andre Majorel <amajorel at teaser.fr>
Subject: Re: [sdiy] Akai S612 filter/schematics
Date: Thu, 18 Apr 2002 09:21:19 +0200

> On 2002-04-18 01:38 +0200, Theo wrote:
> 
> > Don't think your distribution is pink.
> > If memory doesn't fail, pink is 3dB LP filtered white noise (cutoff at 0hz)
> 
> The frequencies of the partials were set by raising a number to
> a random power. I think this is a pink distribution (i.e.
> statistically, each octave contains as many partials as any
> other octave).

In Pink distribution you have equal amount of energy per octave. This
requires a -3dB/oct slope. Trouble is that you can't design a filter
with exactly that slope, but you can approximate it with a bunch of
parallel caps where each has a series resistor. The approximation can
become quite accurate.

> White noise does *not* look flat in a spectrum analyser, as each
> octave has twice as much energy as the octave below.

Right. It rises with +3dB/oct.

Cheers,
Magnus