MOTM

on the 410 triple filter, i understand what the rate and depth controls do 
vis-a-vis the lfo and how it interacts with the filters but where does the 
"sweep" control fit in? what does it actually control?
why only 2 lfo`s and not go all the way and use 3 ?
( i`ve noticed that these triple vcf modules seem to have elicited some 
interest from the modular user community since i`ve seen at least three 
manufacturers that offer them for their systems.  i`ve gang patched multiple 
vcf`s before over the years but never thought of it as a single module.  is 
it interesting enough to acquire or would someone be better off with with 
multiple single vcf`s ? )
best,
dave

> on the 410 triple filter, i understand what the rate and depth controls do
> vis-a-vis the lfo and how it interacts with the filters but where does the
> "sweep" control fit in? what does it actually control?


It is a master sweep for all 3 filter sections. It moves them all *up* in
frequency together
as a group.


> why only 2 lfo`s and not go all the way and use 3 ?

Because 3 sounds really bad!


> ( i`ve noticed that these triple vcf modules seem to have elicited some
> interest from the modular user community since i`ve seen at least three
> manufacturers that offer them for their systems.  i`ve gang patched
multiple
> vcf`s before over the years but never thought of it as a single module.
is
> it interesting enough to acquire or would someone be better off with with
> multiple single vcf`s ? )


Most VCFs do not offer high-Q bandpass as a filter type.

Paul S.

In a message dated 00-01-01 11:36:48 EST, you write:

<< 
 It is a master sweep for all 3 filter sections. It moves them all *up* in
 frequency together
 as a group.
  >>


paul,
thanks for the clarification!
best,
dave

In a message dated 00-01-01 11:36:48 EST, you write:

<< Because 3 sounds really bad! >>



paul,
must be a subjective thing. in the past, i hadn`t noticed this to be a 
problem. ironically, when i would use  3 state variable vcf`s in parallel, 
i`d either drive them all with one control voltage source ( lfo, eg,etc. ) or 
each would have its own. i can`t recall having ever tried it with 2 !  gee, 
the things we can overlook while messing around........
best,
dave

In a message dated 00-01-01 11:36:48 EST, you write:

<< Most VCFs do not offer high-Q bandpass as a filter type.
  >>


paul,
oddly enough, until i got the modular that i`m using now, i never had a 
24db/oct vcf !
all mine were either state variable or variable slope. they all offered a 
bandpass response and fairly high q`s were achievable.
best,
dave

> on the 410 triple filter, i understand what the rate and depth
> controls do
> vis-a-vis the lfo and how it interacts with the filters but where
> does the
> "sweep" control fit in? what does it actually control?

Think of it as a master tune, or master frequency control that moves all 3
filters at once while preserving the tuning intervals between them.

> why only 2 lfo`s and not go all the way and use 3 ?

Probably because the circuit is an improved clone of the Korg 3300's filter
section, which only used 2 LFOs. Also probably cost and panel real estate
issues.

Dave Bradley
Principal Software Engineer
Engineering Animation, Inc.
daveb@...

In a message dated 00-01-03 13:12:36 EST, you write:

<< 
 Think of it as a master tune, or master frequency control that moves all 3
 filters at once while preserving the tuning intervals between them.
  >>


dave,
thanks for the input. paul and others already told me what i wanted to know 
but i appreciate your answering my questions!
thanks!
best,
dave