[sdiy] Thoughts on a Polyphonic Synth

[Dave Kendall]

Hi Jure.

> that's exactly what i've been thinking about for the past weeks.
> my idea is to design voice modules that include something along the lines of
> - 2x VCO with saw/tri/sqr/sin + SUB (shaped?)
> - 2x 2pole SV VCF that can be cascaded into 4pole (with variable spacing)
> - 3x ADSR EG (for each VCO and for VCF)
> - 2x LFO
> - 2x VCA

For the sake of a few extra circuits, It might be a good idea to have some
global modulation sources that affect all voices - another LFO ( even with
just a simple triangle wave for sweeping VCFs or whatever),  sample + hold,
and maybe overdrive/distortion.

A global EG with external triggering is useful too... pulsed chords, or that
trancey stuttering gated chord thang, without tying up an external dual
noise gate..... :-)

The uCapps stuff is amazing, and the possibilities are huge. If you can live
with 4 note poly, then the PolyDAC as a kit gives a whole load of MIDI
controllers too for about the cost of a midibox CV+ AOUT, once the MAX525s
are figured in, and includes CC64 sustain, which is pretty important for
chord work IMO.

cheers,

Dave

> 
> and then you could stack as many as you want to get polyphony of your choice.
> 
> i've got a whole bunch of ideas but since i'm a total n00b i'll learn
> some more before writing about it :)
> 
> jure
> 
> On 3/24/06, harrybissell <harrybissell at prodigy.net> wrote:
>> You would need to duplicate all the modules that you wished for
>> in one voice.  8 eg for the VCF is probably a bare minimum.
>> 
>> You probably would like 2 VCO per voice...
>> 
>> And a way to keep them all in tune. Usually they use a computer
>> to measure the frequency error and compensate per MIDI note number.
>> Lookup table kind of thing...
>> 
>> One thing that is NOT obvious... making a very complex single
>> voice (like for a mono patch) will not be so satisfying in a poly.
>> It will either get 'muddy' sounding... or blend so well that it
>> is totally smooth
>> 
>> H^) harry
>> 
>> Benjamín Velasco wrote:
>>> 
>>> Hi list!!!
>>> 
>>> After looking the amazing midi projects at www.ucapps.de i was
>>> wondering how difficult it would to build for example a 8 note poly
>>> synth. With the MIDI to CV from this page you could have 8
>>> independent for each oscillator. Then you would need perhaps 8 EG
>>> and 8 VCA for each note's volume? What other module you i have to
>>> repeat? Maybe 8 EG for VCF??
>>> 
>>> 
>> 
>