Any textbook study of resonant circuits and, using bilinear mapping a
discrete-time counterpart, 3 dB bandwidths and Q is about a 2nd-order system.
A hemholtz resonator or a comb filter have resonance at many frequencies and
they are much higher order tHan 2. The are also tuned to harmonics.
The 2nd-order section, or "biquad" (with Q greater than 1/2) is resonant to
only one non-negative frequency.
--r b-j [email protected]
"Imagination is more important than knowledge."
-------- Original message --------
From: Stefan Sullivan <[email protected]>
Date: 7/22/2018 9:55 PM (GMT-08:00)
To: A discussion list for music-related DSP <[email protected]>
Subject: Re: [music-dsp] What is resonance?
Oh interest challenge of the definition of resonance. The typical textbook
diagram shows a little local bump at some frequency in a bode diagram, but if
you consider dc the resonant frequency, then the only way to show a bump is by
being higher than all the other frequencies (i.e. monotonically decreasing).
Hmm, I wonder. One common definition of resonance bandwidth is also the "3dB"
point. But I guess resonating at dc is probably not a common use case.
Stefan
On Sun, Jul 22, 2018, 18:11 robert bristow-johnson <[email protected]>
wrote:
I've been wondering about the connection that resonance and filter orders at
least 2. That's 2 delays (and feedback).
But if you're limiting the resonant frequencies to DC and Nyquist, then with a
one-sample delay digital filter, you can have something like "resonance".
Even if the single delay is two samples long (but no tap in the middle), that
allows only DC, Nyquist, or half-Nyquist as tunable frequencies.
So just sayin, in another sense of the word, that "resonance" can be had with a
single *long* delay and one feedback path or with two arbitrarily short delays
and two feedback paths.
--r b-j [email protected]
"Imagination is more important than knowledge."
-------- Original message --------
From: Stefan Sullivan <[email protected]>
Date: 7/22/2018 2:20 PM (GMT-08:00)
To: A discussion list for music-related DSP <[email protected]>
Subject: Re: [music-dsp] What is resonance?
Yes. The term helmholz resonator should be a hint ;) Basically when a sounds
gets added to itself after a delay you end up adding energy to the frequency
that corresponds to that delay amount. For very long echos we don't hear it as
a resonance, but for shorter delays it will boost higher and higher frequencies
into the audible range.
Stefan
On Sun, Jul 22, 2018, 08:10 <[email protected]> wrote:
Hello all
Is "feedback with delay" really resonance? I recognize many people describe the
effects of "room resonanes this way", but to my understanding these are no
resonances in the basic meaning but reflections. A resonance is a self standing
oscillating system like a guitar string or an air mass in a Helmholtz resonator.
Rolf
Gesendet: Samstag, 21. Juli 2018 um 04:33 Uhr
Von: "Andrew Simper" <[email protected]>
An: "A discussion list for music-related DSP" <[email protected]>
Cc: [email protected], [email protected],
[email protected]
Betreff: Re: [music-dsp] What is resonance?
Resonance is just delay with feedback. Resonance occurs when you delay a signal
and then feed it back with some gain to the input of the delay "in phase"
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