I'm really impressed by the ARP 1047

[harry]

Ooooh I know I know..... (teacher call on me...!)

I remember the Dennis Colin paper.  The response with the control centered
is a normal notch, and the Q sets the notch width.  Move it to (lets say) the low
pass
side... and you will get a resonant peak with the Q, followed by a notch above
then the hipass side at reduced amplitude... Move it to the hipass side, and
there will
be a peak on that side, with the notch below.

Is it useful? Beats me.  I did play with this filter for about 20 minutes at the
Berklee
School of Music in Boston. They had an ARP 2500 as a main cabinet, with two
ARP 2600s as low cost "wing cabinets". I was helping a (lucky) student set up
some patches... they didn't know how to run it. I did, thanks to a full size
poster of the 2500
that adorned my wall as a teen. I would look at it an say...."Damn.....
twentythousandfuckingdollars....it costs twice what this HOUSE did."  What would
I choose... the house... or the synth ????

Anyway I got tossed out of the Berklee lab when I got in an arguement with a
professor who said that "pulse width" is the same thing as a "resonant filter".
Did I say "maybe they seem the same when your head is up your @ss ???"  No... I
don't think I said that. But he did say "time for me ... and YOU to go now...."

BTW... I'm GLAD that I don't have a 2500. Those matrix switches (made by Cherry)
were pieces of Sh!t.  They would be dead many times over by now... even with good
care. And the matrix crosstalk really sucked.

This opinion from a man with a PAiA 2720... with an Aries VCO and VCF designed by
(yup)... Dennis Colin.

I nominate Dennis for the DIY Hall of Fame !!!

H^)  harry

Magnus Danielson wrote:

> From: Haible Juergen <Juergen.Haible at nbgm.siemens.de>
> Subject: RE: I'm really impressed by the ARP 1047
> Date: Thu, 14 Dec 2000 16:16:30 +0100
>
> >       >  It has a notch output and there's a balance control to tune the
> >       >  notch zero frequency with respect to the filter tuned frequency.
> > >
> > I'm a little puzzled about this one. What is it good for ?
> >
> > Or is it the same as the variable mix of HP and LP as in the Oberheim SEM ?
> > The off-center position (somewhere between HPF and Notch) is highly
> > useful IMO, sort of resonant HPF without loosing all the bass.
> > But it's nothing I would describe as "tuning the Notch frequency".
> >
> > So, is it the same thing on the ARP filter, or something else ?
>
> I interprent this as the feasability of setting your complex zero
> poles on a separate frequency than the center frequency. Knowing from
> the previous emails in this thread that it is a state-variable filter
> this is simple enougth to do. Heck, I could cook it up around the
> ASM-1 VCF (which is a state-variable).
>
> It is a usefull thing if you know how to use it.
>
> Cheers,
> Magnus