SergeModular

Dear all,
Partly motivated by the current ModCan debate and partly by my success in
finally uploading a file, I decided to run a VERY subjective filter
comparison.
The oscillator mix was NTO sawtooth and ModCan wavetable (controlled via
ModCan standard oscillator). One of each mixed 50/50 via Serge audio mixer.
The filters were: first, Serge Variable Q, Fenix Multimode (filter 1) and
finally ModCan (Polyfusion type). I used a little decay and sustain from the
Serge Extended ADSR to control the ModCan Quad VCA and add a little bite to
the filters via frequency cut off.
I admit to most often using a UAP as the last port of call but whenever I
patch in the ModCan VCA it always sounds ballsy. Speaking only for myself I
could never call it disappointing.
If you download the MP3 (now at Serge files) you will hear the Serge filter
(with a small amount of resonance) being manually swept, followed by the
same filter with the resonance being manually increased. Next up the Fenix,
finally the ModCan.
I've never done this comparison before myself. IMO in these test conditions
the Fenix filter (one of my favourites) sounded the weakest. IMO the ModCan
sounds the richest but falls down when having the resonance swept.
The ModCan has a very rich bottom end and a zingy high end but all those
qualities seem to disappear when the resonance is increased. I think in the
past I have juggled the filter frequency and CV2 inputs to get the filter to
sound bigger when using a high Q.
Anyway, it's all very subjective and quite hard to hear any differences once
converted to an MP3.
BTW the whole thing was run from a Future Retro sequencer (the FR777 in my
case).

>I decided to run a VERY subjective filter
> comparison.
> The filters were: first, Serge Variable Q, Fenix Multimode (filter

1) and

> finally ModCan (Polyfusion type)

Chris,

A great one-shot comparison. Thanks for uploading it. While everyone
will have their own opinion about which sound they prefer, we can all
hear the VFQ perform (and very well, too). Perhaps this will foster
more dicussion about filters from a sonic quality perspective, rather
than a cut-off-slope specification viewpoint.

I used to be in the more-is-better camp. But the VQF is quite
satisfying. Apparently, the resonance peak is larger with lower cut-
off slopes. (See the chart at the bottom of the page for the Doepfer
A-105 VCF7 filter - informative, even if it is specific to the
Doepfer www.doepfer.com/home_e.htm)

Dr P

CW,

Perhaps the Modcan suffers from the lack of compensation in the filter. When resonance is increased, the frequency at the "knee" is amplified (I will continue to use a "leg" metaphor for this description, with the passed frequencies being the "thigh top" and the roll-off being the "shin"). In a filter not designed to compensate for this phenomena, the "thigh top" frequencies will all be decreased in amplitude (volume) and the slope of the filter "shin" will become steeper. This is perhaps the situation with the ModCan, with the bass frequencies losing "punch" when the resonance is increased.

This compensation needs to be specifically designed into the circuit and adds expense to the cost of production. Although I am not certain, I believe the Serge VCFQ has this compensation built in.

Scott

"C. Whitten" wrote:

The ModCan has a very rich bottom end and a zingy high end but all those qualities seem to disappear when the resonance is increased.

CW,

Perhaps the Modcan suffers from the lack of compensation in the filter. When resonance is increased, the frequency at the "knee" is amplified (I will continue to use a "leg" metaphor for this description, with the passed frequencies being the "thigh top" and the roll-off being the "shin"). In a filter not designed to compensate for this phenomena, the "thigh top" frequencies will all be decreased in amplitude (volume) and the slope of the filter "shin" will become steeper. This is perhaps the situation with the ModCan, with the bass frequencies losing "punch" when the resonance is increased.

This compensation needs to be specifically designed into the circuit and adds expense to the cost of production. Although I am not certain, I believe the Serge VCFQ has this compensation built in.

Scott

"C. Whitten" wrote:

The ModCan has a very rich bottom end and a zingy high end but all those qualities seem to disappear when the resonance is increased.