Hi,
The
filter is a SSM2040 (lot of people say it's the best VCF chip). If you check
the Crumar schematics then it's wired almost exactly as shown in SSM2040
data sheet as "voltage controlled lowpass filter with voltage controlled
resonance. The frequency control input sensitivity is 1
volt/octave."
Voltage controlling resonance is driven by RESONANCE
fader. Voltage controlling the filter comes as the sum of three
components:
-
envelope (generated by SSM2050) which you control with ATTACK and DECAY
faders;
- LFO
(which comes from MODULATION section when the button is in VCF
position;
-
voltage controlled by RANGE fader. Actually, range of the RANGE (pun intended!)
can be calibrated with the pot TH1 on the BRASS board. If the filter does
not sound sharp enough maybe you should adjust that. As far as I can tell it's
24dB...
Any
comments?
If
anyone else out there has played around with adjustment pots on the boards would
you pls share your experiences and ideas.
-----Original Message-----Hi there,
From: cragulauk [mailto:craig@...]
Sent: 05. August, 2003 15:08
To: crumar@yahoogroups.com
Subject: [crumar] Re: Performer "EQ Control"
I'm not 100% about this, but I'd imagine they are fixed bandwidth (ie
preset frequency range) parametric eq controls, ie non-resonant
filters: low shelf for low, band pass for middle and hi shelf for
high.
A filter is basically parametric eq, but with resonance (positive
gain at the cutoff frequency) that follows the cutoff frequency.
Parametric eq can create the same kind of sounds as a filter, indeed
it is a type of filter, but you try doing a sweep down all those
knobs or faders!
While we're on the subject, does anyone know what kind of filter is
used on the brass section? It must be low pass just cos of how it
sounds and I'd imagine that it's less than 12dB/octave as it's fairly
weak compared to many 12 or 24dB filters.
I do love those squelchy bass sounds it can make. Great sampled as a
chromatic scale, recycled and played back on yer sampler via your
fave sequencer for wicked sequences.
If anyone knows any better, please put me straight!