[sdiy] RE: [AH] Parametric EQ

[JH.]

Well ... "neutral" sounding parametric EQs are cheap in software, nowadays.
A parametric EQ with "character" would be interesting - and I intended to offer a clone of the Moog Parametric EQ.
But then I made a PCB for the Polymoog Resonator section, and this has been such a success that I hesitate to follow thru that first 
idea, because there is so much "overlap". The Polymoog Resonator has 3 fully parametric bands, but the control is slightly different 
to an ordinary EQ. Like a parametric EQ, it has Bandwidth, Frequency and Gain controls for each channel. But unlike an ordinary EQ, 
there is no (direct) function for attenuating a band. You can only boost, and mix with a dry signal. But there are different 
functions for each channel: The usual BPF, but also a BPF-Notch, a LPF and HPF.
It's probably not as predictable as an ordinary EQ, but it's very intuitive and "organic" sounding.
(I still have PCBs available for this, so yess, it was a bit of advertising, too.)
(I know of at least one person who has made the individual frequencies voltage controlled, using Vactrols.)

http://www.jhaible.de/resonator/resonator.html

JH.

----- Original Message ----- 
From: "Greg James" <gjames at kddlab.com>
To: "'Analogue Heaven'" <analogue at hyperreal.org>
Cc: "'synth-diy'" <synth-diy at dropmix.xs4all.nl>
Sent: Saturday, February 20, 2010 11:58 PM
Subject: [sdiy] RE: [AH] Parametric EQ


I've suggested this before (maybe on other lists): It would be swell if
someone designed a single-channel parametric EQ PCB that allowed full
control over frequency, bandwidth, gain, and whatever else could be thrown
in for good measure. Then, the DIY crowd could adapt it to whatever format
they wanted. Did I mention CV control of the parameters? One could then
decide how many channels they want (3, 4, 16???) to build out a super EQ of
their own size. I know I'd be interested in doing this in MOTM format.

Jeurgen? You listening? :)

-Greg
(unfortunately NOT an electrical engineer)

-----Original Message-----
From: John Mahoney [mailto:jmahoney at gate.net]
Sent: Saturday, February 20, 2010 5:30 PM
To: Analogue Heaven
Subject: Re: [AH] Parametric EQ

At 03:38 PM 2/20/2010, mister dwan wrote:
>...
>The AFC-2 is the secret weapon.  ...  4 completely parametric EQs...

To be precise, they are semi-parametric, as the bandwidth (Q) is not
adjustable.

However, that shouldn't stop anyone from trying there, as everything
I've seen raves about the Toft EQs.

John


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