Wiardgroup

an edifying post, Mr. Chang.... thanks!

i'd like to add one small factoid:
The Buchla design for a lowpass gate exhibits a dynamic attenuation of
the harmonic spectrum that is very close to the characteristics of a
real physical sound source fading into the distance. I can't declare
whether this was a deliberate effort on Don Buchla's part or not, but
given his deep roots in physics, i'd be willing to bet it was no
accidental coincidence.

-doc


--- In wiardgroup@yahoogroups.com, "Gary Chang" <gchang@...> wrote:
>
> I wanted to post a note about the "Lowpass Gate" and its usage
> throughout electronic music, for the purpose of clarifying why some of
> us have obsessed about them....
> 
> From the 200 Series Brochures, circa 1970s:
> 
> "The Model 292[Quad Voltage-Controlled Lopass Gate], with the
> capability of simulating the spectral and amplitude changes that
> accompany a receding sound source, is one of several Electric Music
> Box modules that can deal with spatial localization and movement."
> 
> There were three opreation modes for these devices - filter, vca and
> dual.  Obviously, when in dual mode, the lopass gate operates as both
> - a filter(6db/oct) and a VCA.
> 
> This dual mode is the sound of Mort Subotnick's electronic
> realizations of the 70's.  It has a characteristically "woody" chirp
> to its transient character.  It is this mode that most of us who used
> the old Buchlas miss, hence the quest for "LowPass Gates".
> 
> The issue with the recent versions of this circuit is that most of the
> versions of the the LP gate is that they are too slow.  When hit with
> a short transient, they tend to ring excessively, making the "uber
> marimba" patch made famous by Subotnick all but impossible without
> slapping a VCA after the gate to shorten the sound.  The old Buchla
> had only a 1v ptp audio signals, so the vactrol didn't have as far to
> go to open all the way up, compared to the 10v ptp audio signals found
> on Wiard and many other systems, so it was very quick.  As a matter of
> fact, even the new 200e has very slow lopass gates, needing a second
> gate in VCA mode to shorten the ring.  This is not typical of the 70's
> 200 series 292 gates.
> 
> Then in comes the Borg2, and we have a perfect 10v ptp lopass gate -
> even better than the original (which are 1v ptp and had a "dual
> linear" - as opposed to logarithmic cv curve).  
> 
> I also love to use the original Borg Filter for multichannel panning
> with the JAG, because it rolls off the distant channels (just like the
> 227 quad locator of the Buchla 200 system), while opening up to full
> bandwidth where the sound is nearer.
> 
> So, that's the lowdown on this LowPass Gate business....
> 
> gary
>