[Re: adding notch to SV filter]

[M.Ruberto]

"so i see" said the blind man to his deaf wife. yeah, i just found this out
the hard way. i spent most of the day repairing a cracked PCB on a Kawai
K5000, then i spent the rest trying to get a good notch from the filter.
subtraction didn't work. adding worked, but the effect was so subtle i decided
it wasn't worth the extra parts. i do have a perfectly good phasor pedal here
too ;)

thanks

-<mike>-



Harry Bissell <harrybissell at prodigy.net> wrote:
> Summing the HP and LP outputs is THE way to go. If you subtract the bandpass
from
> the input, it only works for one "Q" setting. Adjust Q and you have to
adjust the
> gain also.
> 
> So this will work only at one point... part there the signal looks like a
bandpass
> again with
> funny phase inversion.
> 
> This was a technique used on the old PAiA 2720... it did work, with the
limitation
> above.
> 
> H^)  harry
> 
> PS: IMHO the allpass (phase shifter) is more usable than the single notch.
> 
> "M.Ruberto" wrote:
> 
> > hi,
> >
> > i'm building a standard state variable filter and i would like to have a
notch
> > output in addition to the HP, LP and BP. is it acceptable to obtain it by
> > subtracting the BP from the input signal? or is there some less simple
but
> > more correct way of doing this?
> >
> > thanks
> >
> > -<mike>-
> >
> > ____________________________________________________________________
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