[sdiy] Ideal polyphonic digital reverb

Tue Mar 23 05:56:02 CET 2021

Quite a lot actually. The SDD line are all really different from each other - the SDD-1200 and SDD-3300 being my favorites.

The 3300 is really unique. It has 3x inputs, call them I1, I2, I3, 3. 3x outputs O1, O2, O3.  3x delays A, B, C. For *EACH* delay you specify how much signal from each input I1, I2, I3 and each of the delays A, B, and C is going into the delay. So, routing the output of delay A back into itself is your feedback setting. You then specify how much output from the delay is being routed to O1, O2, and O3. Each of the amounts goes from -15 to ±15 so you have negative feedback and inputs as well as positive. What's important to keep in mind is that this is nit an either/or situation. All inputs and delay outputs are available simultaneously for all 3 delays. Each delay A, B, and C has its own delay time and there are 3 LFOs to modulate things.

It's super trippy as you basically can send anything to anything however you want. I have 3 of them. Massively underrated and I can't believe how cheap they are. 

I run mine in "stereo" with I1, I2 coming from my DAW sends and O1, O2 returning to the DAW. I have O3 from one unit patched into I3 of a second unit and the O3 of the second unit patched back to I3 of the first unit. This way, I can feed the two machines to each other. When I really want a mess, I use a matrix mixer (Auxpander) to patch everything to everything on sends. I havent tried putting  a reverb unit in the middle but you can bet I'm going to.

James

On Mar 22, 2021, 11:14 PM, at 11:14 PM, cheater cheater <cheater00social at gmail.com> wrote:
>can you both tell me the difference between an sdd 3300 and an sdd
>3000? thanks.
>
>On Tue, Mar 23, 2021 at 3:41 AM Michael E Caloroso
><mec.forumreader at gmail.com> wrote:
>>
>> Want more intriguing?
>>
>> MC
>>
>> On 3/22/21, James Coplin <james at ticalun.net> wrote:
>> > As someone with 3x SDD-3300s sitting here this intrigues me
>mightily.
>> >
>> > James R Coplin
>> >
>> > On Mar 22, 2021, 8:56 PM, at 8:56 PM, Michael E Caloroso
>> > <mec.forumreader at gmail.com> wrote:
>> >>After years of experimentation I have concluded that a polyphonic
>> >>synth needs both reverb and at least a pair of delays that can be
>> >>modulated.
>> >>
>> >>Reverb alone was never enough.
>> >>Modulated delays alone was never enough.
>> >>
>> >>I had really liked my Korg SDD-3300 triple digital delay for
>synths,
>> >>which can be configured in any series/parallel/cross-coupled
>> >>architecture you can dream of.  This gets better modulated delays
>than
>> >>multi-effect boxes.  Then I saw a spare output and two spare inputs
>on
>> >>the 3300, so I hooked my Lexicon PCM60 digital reverb up to it and
>> >>that was the magic combination I wanted.
>> >>
>> >>Using the 3300 I can route direct signal to reverb, then process
>the
>> >>reverb tales with the 3300.  Or reverb in parallel with delays.  Or
>> >>series.  Add predelay to the reverb send.  Or multiple predelay
>each
>> >>to different delay times.  World of sounds with this combination.
>> >>Enough that I built seven sets of these for my synths for
>independent
>> >>processing.
>> >>
>> >>MC
>> >>
>> >>On 3/22/21, cheater cheater <cheater00social at gmail.com> wrote:
>> >>> let's enumerate some of the possibilities:
>> >>>
>> >>>
>> >>> voice 1: vco1 -> (a1) -> vcf1 -> (b1) -> vca1 -> (c1)
>> >>> voice 2: vco2 -> (a2) -> vcf2 -> (b2) -> vca2 -> (c2)
>> >>> ...
>> >>> voice n: vcon -> (an) -> vcfn -> (bn) -> vcan -> (cn)
>> >>>
>> >>> at a1, you want to have one of a few things:
>> >>>
>> >>> (i) a convolution engine that takes the output of vco1, applies
>an
>> >>IR,
>> >>> and puts it into the input of vcf1
>> >>> (ii) same as (i) but the input is all vcos (1..n) and the output
>is
>> >>vcf1
>> >>> (iii) same as (i) but the output is all vcfs (1..n)
>> >>> (iv) same as (i) but the input is the last few notes you played
>in
>> >>> decreasing order: 1/2 * the vco from the most current note + 1/4
>*
>> >>the
>> >>> vco from the previous note + 1/8 * the vco from the note previous
>to
>> >>> that etc
>> >>> (v) same as (iv) but you do that with the outputs
>> >>> (vi) same as (i) but there's also input from b1 or c1
>> >>>
>> >>> then you want the same topology at b and c
>> >>>
>> >>> They're all obviously going to have different results and
>different
>> >>> applications.
>> >>>
>> >>> And obviously you can think about all sorts of dsp in here, not
>just
>> >>> convolution, and when it comes to convolution, then not just
>reverb.
>> >>>
>> >>> On Mon, Mar 22, 2021 at 7:03 PM Mike Bryant
>> >><mbryant at futurehorizons.com>
>> >>> wrote:
>> >>>>
>> >>>> Thought I'd change the topic name as we're definitely moving
>away
>> >>from
>> >>>> cheap.
>> >>>>
>> >>>> So given a polyphonic synth with unlimited voices and unlimited
>> >>budget,
>> >>>> what should the structure of an ideal reverb system look like ?
>> >>>>
>> >>>> Once there's a consensus I'll try coding it into my digital
>synth.
>> >>>>
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