[sdiy] Resonator type filters

[Bernard Arthur Hutchins Jr]

Mattias -  good comments


What you say seems correct, except for the difficulty of ascribing pitch to short signals.


If you ping a sharp bandpass, it rings essentially at the center frequency. if you ping it with an extended impulse train, the pitch generally becomes the pitch of the impulse train.This I recently discussed:


http://electronotes.netfirms.com/EN229.pdf

<http://electronotes.netfirms.com/EN229.pdf>For a moderate number of equally spaced impulses, you get (as you suspect) an intermediate result.  But the tones may well be so short (delta-T is small) that the pitch is poorly heard (delta-F is large  - Heisenberg).

With a set of several resonances (let along 39 of them) expect and hope for something very interesting.

I kind of suspect that it is not pitches altered by the filters to a different scale, but rather the imposition of residual non-harmonic partials (unfamiliar instruments) that leave the major impression here.

Description of what is heard kind of rules over theory here!

Bernie

________________________________
From: navelludd at gmail.com <navelludd at gmail.com> on behalf of Mattias Rickardsson <mr at analogue.org>
Sent: Wednesday, July 5, 2017 10:55 AM
To: Bernard Arthur Hutchins Jr
Cc: synth-diy at synth-diy.org
Subject: Re: [sdiy] Resonator type filters

On 3 July 2017 at 21:04, Bernard Arthur Hutchins Jr <bah13 at cornell.edu> wrote:
> A lot of questions here about how a filter bank is used and what it sounds
> like are addressed in EN116 which I posted.
>
> Basically, if nothing moves, it sounds like nothing: like sawtooth in,
> different complex waveform out - equally boring.  If something does move
> (modulation, starts/stops, live music) it sounds tinny.    I remember well
> listening to music on the radio through the bank, turning the Q up, and
> discovering that the western music sounded like eastern music.  Possibly a
> useful reference comment.

Oh, so it's some kind of longitude modulator then? ;-)

I think this could partly be caused by another side effect than the tinnyness:

Resonances shift the [percieved] pitch of short notes, when the
resonant frequency is a bit off from the note's fundamental frequency.
This is because the partials of a short note are spread out a bit in
the spectrum due to the limited time it exists, and an nearby
resonance can easily ring louder than the expected frequency of the
note. (Just like listening to bass notes in a room with untreated room
modes - the bass gets muddy not only by smearing in time, but it even
gets hard to hear the pitches of the notes - you end up listening to
the strongest room modes instead.)

So perhaps the music got "out of tune" when run through all the
resonances, and it sounded like oriental scales rather than western?
:-)

/mr
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