AW: Harald Bode Patent (was Re: Another kind of Phasing)

Haible Juergen Juergen.Haible at nbgm.siemens.de
Wed Jan 14 12:44:54 CET 1998


>I think what's happening here is that you've got a new implementation
>of a motorized (ie., Shepard tone, barber pole, continuously
>ascending) phase shifter.

[...]

>Is that what it sounds like to you?
	[...]

	>   HarOld, as I thought, but HarAld).  He has one which may
just be the
	>   infamous Barberpole phaser.  The number is 4399326.  
	>
	>Well, that's pretty much Juergen's circuit.  
	>
	>(Note that it was filed yesterday, 17 years ago!)
	>

I almost *knew* someone must have invented this before (;->) -
nothing's new under the sun.

First I have to say that what I have build does *not* sound like
a countinously rising phaser. It sounds periodic, with the rate of
the quadrature oscillator. My only finding was that is sounds
a little different than an ordinary phaser, so that it would be
worth mentioning.
But this Bode patent seems to do much more. I have just downloaded
it and taken a brief glance, but I will give it a close look tonight.
Most of the things Bode describes should be easily patchable
on my Modular, plus the frequency shifter. I didn't try to include
an ordinary phaser in the feedback loop so far, only BBD delays.
(A short BBD delay in a FS feedback configuration gives a nice
shattering spring-like reverb.)

> >(JH's might be an improvement; I'm not convinced HB's initial phase
	>shift circuit is necessary.)

At first I thought why an extra phase shift before the dome filter -
the dome filter produces enough common phase shift on both
branches (in order to produce a 90deg differential shift), so
why an extra phaser? But it seems that Bode suggests a complete
Phaser device (i.e. comb filter) at this location, not just an 
all pass filter. But well, that's easy to try, I have enough phasers
at home to try this. And these motorized pots might be emulated
with another quadrature VCO and an Interpolating Scanner.
Can't await to try it.

JH. 



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