Wiardgroup

Hi again,

In spite of the fact that I have more filters than I ever dreamed I would 
have, I'm remain pretty stuck on buying one of the professor's.  My heart 
says boogie very loudly, but my mind won't let me discount the borg just 
yet.  I know the answer is get both but at present only one is possible.

I do have a few questions that may tip the balance:
- the boogie can also operate like a low pass gate, correct?  If so, I am 
also correct in thinking that the number of poles determines how quickly the 
gate will decay? i.e. each output will have a difference response 
characteristic.
- how does resonance work in the case of the boogie?  Does it center on one 
of the poles or is it across the entire circuit?  Is the resonance behaviour 
different for each pole?
- I know it's possible to turn the boogie into a high pass filter by 
inverting the phase relationship of some of the outs and mixing them all 
together.  Is it also possible to make a band pass filter like this?

thanks very much,

rgds

Pierre

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Hi Pierre,

--- In wiardgroup@yahoogroups.com, "Pierre Zeeman" <pierrezee@...> wrote:


> - the boogie can also operate like a low pass gate, correct?  

yes

>, I am 
> also correct in thinking that the number of poles determines how
quickly the 
> gate will decay? 

the number of poles affects rate of decay , but it affects other
parameters too.
This might help as a foundation:
http://www.buchla.com/historical/b200/index.html
also, it might help to look up message # 1795 on this group


> - how does resonance work in the case of the boogie?  Does it center
on one 
> of the poles or is it across the entire circuit?  

i'm not sure i completely understand the question but i'll give it a
try...
The boogie's resonance centers on the corner (alternately called the
'cutoff' frequency. When this corner freg moves the resonance-center
moves with it. ('poles' refer to the 'steepness' of the slope at which
  frequencies are attenuated) 
In terms of general behavior, the boogie functions very much like a
'classic' analog resonant filter


 i'm at a loss on this query..(sorry)

> Is the resonance behaviour 
> different for each pole?

> - I know it's possible to turn the boogie into a high pass filter by 
> inverting the phase relationship of some of the outs and mixing them
all 
> together. 

and this answer is a 'best guess'

> Is it also possible to make a band pass filter like this?
> 

i doubt it. I think a bandpass filter would require two VC filters of
the boogie's type ...

hope that helps a little,
-doc