[sdiy] Akai S612 filter/schematics

[Andre Majorel]

On 2002-04-17 16:05 +0200, Joris wrote:

> Btw from the data sheets ( http://www.national.com/ds/MF/MF6.pdf ) it
> seems like there is no resonance peak in these lowpass filters, but my
> ears tell me there *is*. Any thoughts on this?

Not sure, but... I once generated band-limited pink noise by
adding sines with random frequencies between two frequencies one
octave apart, with a pink distribution. Unless there was a bug
in my program, its output would have looked like this on a
spectrum analyser :

           ______
                              Amplitude vs. log of frequency
  _________      ________

The top end of the band was like a low pass filter with vertical
slope (infinite dB/oct), and no resonance. And yet it sounded to
me like there was a peak around the cutoff frequency.

So either there was a bug in my program or this is the audio
equivalent of an optical illusion, a psychoacoustic illusion.

-- 
André Majorel <URL:http://www.teaser.fr/~amajorel/>
std::disclaimer ("Not speaking for my employer");