[sdiy] Craig Anderton's Multiple Identity Filter

[rsdio at audiobanshee.com]

Hi Andrew,

You gotta say which "Matrix" you're talking about. The Oberheim Matrix-12 is two Xpander voice boards in a keyboard. The Matrix-12 has the exact same filter features as the Xpander because the whole voice architecture is the same. The only difference is that the Matrix-12 has twice as many voices, and twice as many Zones.

(Strangely, the Xpander only has 3 Zones, making it a little more difficult to do multi-timbral analog from a MIDI guitar, whereas the Matrix-12 has 6 Zones. Then again, I think you can still assign one string to each voice.)

You're probably thinking of the Oberheim Matrix 6 keyboard and Matrix 1000 rack, which are very crippled compared to the Matrix-12 and Xpander.

Brian


On Oct 26, 2016, at 6:57 PM, Andrew Simper <andy at cytomic.com> wrote:
> 
> Hi David,
> 
> As far as I remember the Oberheim Matrix only had a fixed 4 pole
> cascade type low pass filter, did you mean the Oberheim Xpander? If so
> then yes this is the easier way to generate different responses by
> taking weighted sums of the output of each stage, but you don't get
> the "correct" responeses, you get sags above the cutoff in the band
> pass and high pass modes, and amplitude attenuation below cutoff with
> changing resonance in all modes, which kind of sounds like changing
> the cutoff upwards with increasing resonance in band pass and high
> pass modes, but the resonant peak stays put.
> 
> Cheers,
> 
> Andrew
> 
> On 27 October 2016 at 03:23, David G Dixon <dixon at mail.ubc.ca> wrote:
>> I've got a filter design called the "Polaris" that gives nearly 30 different
>> useful filter modes in a much simpler say than the MIF, and doesn't need a
>> Curtis chip to do it.  Intellijel sells it for $229.  If you want to check
>> it out, go here: https://intellijel.com/eurorack-modules/polaris/  It's
>> based on a Roland-esque cascaded-stage four-pole filter, and takes
>> inspiration from Grant Richter's old Oberheim Matrix multimode filter
>> design, but it goes a fair bit further than that.  The mode switching is
>> done with a microcontroller generating a 17-bit code which controls five
>> analog switches, which I still don't know how to do, so I don't have a
>> handmade version of it yet.
>> 
>>> -----Original Message-----
>>> From: Synth-diy [mailto:synth-diy-bounces at dropmix.xs4all.nl]
>>> On Behalf Of KA4HJH
>>> Sent: Wednesday, October 26, 2016 8:55 AM
>>> To: sdiy
>>> Subject: Re: [sdiy] Craig Anderton's Multiple Identity Filter
>>> 
>>>> On Oct 26, 2016, at 4:37 AM, Andrew Simper <andy at cytomic.com> wrote:
>>>> 
>>>> From what I can see with Craig Anderton's filter it won't actually
>>>> give the "correct" responses for all the different filter types unless
>>>> there is a way to switch the polarity of the resonance, and also where
>>>> the resonance is added. Am I missing something? Sorry if I've posted
>>>> all this stuff before.
>>> 
>>> This is one of the reasons I reposted the link. I remember
>>> some discussion about this and wondered how Craig's design compared.
>>> 
>>> 
>>>> On Oct 26, 2016, at 12:30 AM, Doug Terrebonne
>>> <dougt55 at yahoo.com> wrote:
>>>> 
>>>> The MIF article has been on synthdiy.com for a long time -
>>>> http://www.synthdiy.com/files/2002/MIF.pdf
>>> 
>>> I didn't even know it was there.
>>> 
>>> 
>>>> On Oct 26, 2016, at 5:43 AM, Roman Sowa <modular at go2.pl> wrote:
>>>> 
>>>> Why use predatory file hosting sites while there are sites
>>> like synthdiy.com or synth.net, which AFAIK are managed by
>>> this list members.
>>> 
>>> I completely forgot they existed but then this is the first
>>> time I've received a complaint about Mediafire.
>>> 
>>> 
>>>> On Oct 26, 2016, at 5:43 AM, Roman Sowa <modular at go2.pl> wrote:
>>>> 
>>>> Why use predatory file hosting sites while there are sites
>>> like synthdiy.com or synth.net, which AFAIK are managed by
>>> this list members.
>>>> 
>>>> If anyone's interested I can also host any doc files (no
>>> audio/video/warez or any pirated stuff) at regular downolad
>>> links, no ads, no download buttons or popups.
>>> 
>>> 
>>> Good to know. I may take you up on it.
>>> 
>>> 
>>> Terry Bowman, KA4HJH
>>> "The Mac Doctor"
>