200e

Hello,

Is it possible to control the cutoff frequency with the knobs without  
stepping?
I read that it is calibrated in semitones. This is very weird, it  
should be the harmonics of the harmonic series.

At 11:05 PM +0300 10/11/06, Alex Pi wrote:
>Is it possible to control the cutoff frequency with the knobs without 
>stepping?
>I read that it is calibrated in semitones. This is very weird, it 
>should be the harmonics of the harmonic series.

The knob is not a pot, but rather a rotary encoder, so it is inherently stepped. The filter response is smooth when responding control voltages or the internal arbitrary function generator, though.

- C

-- 
Chris Muir           | "There are many futures and only one status quo.
cbm@well.com         |  This is why conservatives mostly agree,
http://www.xfade.com |  and radicals always argue." - Brian Eno

hello alex, and everyone.

here are my answers. i hope they help!

-   the knob on the 291 is really a rotary encoder with a moderate number of
discrete positions. given that fact, don decided to map each position to a
hz value in 12tet. although this is, strictly speaking, as arbitrary a
mapping as any, it at least has the benefit of being familiar to most
people. personally, i sometimes find the semitones to be very useful; other
times i don't really care (like whenever q is not super high.)

-   when you continuously sweep a narrow band filter over an input wave, you
would typically hear harmonic partials because they are present in the
sound, not because they are built into the filter circuit. if the input
sound is a gong or cymbal (or a non-linearly-coupled spring equation), you
will hear enharmonic partials, and if the input spectrum is filled with
noise you will hear random pitches.

-   the cv inputs of the 291e are not discretized; they dump voltage
directly onto the circuit in the same manner as the original 291 dual
filter. thus one could sweep the center frequency by other means (e.g. a
knob on the 255, 256e, or 250e, a volume pedal, or a large magnetic
pendulum) and hear the component frequencies of the input sound emphasized
without prejudice, whatever they may be. such continuous sweeping can also
happen between stages in the 291e (hence, 'morphing').

ok!

eb

On 10/11/06, Alex Pi <alexpi@tellas.gr> wrote:
>
>   Hello,
>
> Is it possible to control the cutoff frequency with the knobs without
> stepping?
> I read that it is calibrated in semitones. This is very weird, it
> should be the harmonics of the harmonic series.
>
>  
>


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