Sequential Circuits Prophet VS envelope

Hi,

I'm looking for someone who can make adjustments to a patch created by Peter McCulloch, which he shared on this page: https://cycling74.com/forums/analog-style-adsr-envelopes/

I was unable to reach Peter, so I'm looking for someone else who might be interested. After I have payed and the job is done, I wouldn't mind (with the programmer's permission) to post the new patch on the original page so everyone can use it.

If you are interested, send me a PM and let me know the cost: nils.vanderplancken (at) telenet.be

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My idea:

As it is now, the patch is an ADSR, with (as is always the case)

- a fixed attack-starting-level of 0
- a fixed attack-ending-level of 1
- a fixed rerelease-ending-level of 0

I'd like to expand this ADSR into more complex envelopes found in the classic vintage synthesizer, the Sequential Circuits Prophet VS (1985). The prophet VS not only allows you to adjust the 3 fixed levels mentioned above, but also adds another point and is capable of making repeats (loop points).

These kinds of envelopes are very interesting when for example controlling the LFO rate. The manual describes these envelopes in a very easy way:

"When a key is pressed, the envelope begins at a LEVEL X, proceeds to LEVEL A at RATE A, proceeds to LEVEL B at RATE B, to LEVEL C at RATE C. These are all linear (same-rate) movements. Provided the key is still held, the envelope will remain at LEVEL C (=sustain level). Whenever the key is released, the envelope falls to LEVEL D at RATE D."

So, you can transform these VS envelopes it into a simple ADSR (for example A: 200ms, D: 100ms, S: 0.9, R: 900ms) by doing:

LEVEL X: 0
RATE A: 200ms
LEVEL A: 1
RATE B: 100ms
LEVEL B: 0.9
RATE C: 0  (doesn't matter in this case as it connect two point with the same level)
LEVEL C: 0.9
RATE D: 900ms
LEVEL D: 0

you can add a delay stage of 500ms to this ADSR example by doing:

LEVEL X: 0
RATE A: 500ms
LEVEL A: 0
RATE B: 200ms
LEVEL B: 1
RATE C: 100ms
LEVEL C: 0.9
RATE D: 900ms
LEVEL D: 0

As mentioned before the prophet VS was capable of looping the envelopes. As the manual describes it:

"If the loop is off, then the envelope remains at LEVEL C for as long the key is held. But by using looping, echo effect, LFO effects, re-strike effects can be created. 6 options were available:"

LEVEL X => LEVEL C
LEVEL A => LEVEL C
LEVEL B => LEVEL C

LEVEL X <=> LEVEL C
LEVEL A <=> LEVEL C
LEVEL B <=> LEVEL C

So, in the first 3 options, a segment of the envelope is repeated, always going left to right.
In the last 3 options a segment of the envelope is looped but 'ping-ponged', going left to right and right to left between the looped points.

I have attached an example from the manual, showing these loops.

In these examples LEVEL X is called point 0, LEVEL A is called point 1, LEVEL B is called point 2, LEVEL C is called point 3 and LEVEL D is called point 4

please let me know if creating such a patch for a good fee is of interest ,

Kind regards from Belgium,

Nils Van der Plancken