[sdiy] Flanger???

[jhaible]

Here's a hint about using BBDs in Flangers:
Keep the signal level in the BBD chip *low*.
You can often read about adjusting for symmetrical
signal clipping, and of course you're tempted to
make the signal as large as possible because of
the poor SNR. But even before the signal is
clipping, it's slightly distorted. This can be
a good thing in a chorus ("warmth"), but
in a flanger it will ruin the effect. Why? because
a Flanger works with *cancellation* of certain
frequencies (comb filter), and this includes
higher harmonics. But if one signal (the BBD-delayed
one) is ever so slightly distorted, it has different harmonics
and these will not cancel with the straight signal.
So let the signal peaks be at least 6dB *below*
clipping point. If it's too noisy then, use a compander.
And yes, Delta Lab Delays make great Flangers!

BTW, I heard that the new MAM Flanger is similar to the
Deltalab method. My relations to MAM are not as close as
they used to be, so I have not heard the final product myself.
Anybody on the list had a chance to hear it?

JH.


> Well as u know I am not a 'friend' of the BBD
> (Bucket Brigade Delay) but I wouls check out
> Juergen Haible's clone of the Eventide Flanger
> "Storm Tide Flanger"... it is probably as good
> of a circuit as you will ever find.
>
> A LOT of BBD based circuits suffer from pretty
> poor noise performance. (read... 'extremely poor')
>
> Phasing and Flanging are really different. In
> Phasing, the notches are not harmonic related...
> in Flanging they are. Phasing is usually done with
> all-pass filter designs... Flanging is done with
> delay lines.
>
> I'd look for some old Delta-Lab Effectrons (for cheap)
> if you want flanging.  If you have two delay lines...
> you can set one for a fixed, short delay (maybe 1ms) and
> vary the other one... allowing through-zero flanging
> (a VERY cool effect)
>
> H^) harry
>
>
> >From: Peter Grenader <petergrenader at mksound.com>
> >To: Nihil Chimeraea <nihil at torgoth.com>, <synth-diy at dropmix.xs4all.nl>
> >Subject: [sdiy] Flanger???
> >Date: Wed, 22 May 2002 21:42:59 -0600
> >
> >Guys,
> >
> >After finding that the Analog System's Comb Filter was sort of a bust in
as
> >far as flanging,  I have been looking around for one and had a crazy idea
> >just to modify a store bought guitar pedal with a VC input or two.
> >
> >Then, I found this circuit on John Hollis' site:
> >
> >http://www.hollis.co.uk/john/ultraflanger3.jpg
> >
> >You will see there an LFO on the bottom left which is generating the
sweep,
> >and figured this is the place to plop in the VC input.
> >
> >Does anyone have any experience with this particular circuit, or could
any
> >of you recommend another circuit which would do the job?
> >
> >A clarification on Analog System's Comb FIlter:  I am not meaning to spam
> >one of my fav synth builders, not at all.  Their multi=mode filters are
one
> >of the sweetest out there. Their Comb Filter did not give the effects I
was
> >after in flanging or phasing, that's all.  It kind of is an auto Adrian
> >Belew generator, as anything going into it tends to sound like Ade coming
> >out.  This isn't a bad thing, it just didn't do what I wished, so I
swaped
> >it for a Doepfer phasor. Am still in need to that all powerful flange
> >however.
> >
> >Let me know and thanks,
> >
> >Peter
> >
> >
>
>
>
>
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