Sequential Vintage Knob Analysis and Recommendations - Prophet 6

A technical overview of the Vintage Knob implementation in new Sequential Prophet 6, OB-6, and Prophet 5 Rev 4. I spent several hours analyzing the Oscillators, Envelope ADR timings, and Filter characteristics. This video explores the vintage knob behavior in depth, and also offers up some recommendations on how adjusting the values could greatly improve the usability of the Vintage Knob across a range of values.

I hope Sequential will consider these recommendations. I've been researching per voice variance over the past few years, and spent hundreds of hours working on voice modeling on various VCO, DCO and digital synths. My expectation is that it would probably be a trivial task to make these adjustments, and would result in improving the behavior and reducing weird dissonance and wonky sound on some patches.

The optimal solution / (feature request) would be to add a third option to the Globals 3 / Parameter 4... so instead of two choices (Slop, Vintage), you have three (Slop, Vintage 1, Vintage 2)... Based on the analysis I did on P6, it appears that there's probably just a small array/table of static values that represent max position of the knob, so I'm assuming it probably wouldn't be a gigantic undertaking to do so... could be as simple as pointing the knob to a separate set of a couple dozen static values. (though I could be wrong... I'm just projecting based on being a programmer for day job... it could be more involved)

A couple additional notes I forgot to mention in the video:
1. The issue with the extreme ADR timings is actually compounded in that the 8-9sec delta between voices 5/6 for Attack, have extreme offsets on the same voices for Decay/Release. So if you combine the variance together, you get upwards of 18 seconds difference in timing for the completion of AD stages of two consecutive voices. It just sounds so wonky when using longer attack/decay times for pads or other evolving sounds. Too much ADR timing variance, and the round robin / offset order compounds the issue further.

2. I know the initial response by some might just be: "Well, just turn down the knob, problem solved"... While this solution is valid for many other controls, this single Vintage Knob controls a variety of different parameters, and they are all "off by different magnitudes" in my opinion. The Osc 1/2 tuning range is great as is, the ADR timings need to be divided by /2 and the filter cutoff should be divided by /5 to get reasonable values -- based on my experience doing voice modeling over the past couple years and researching this topic thoroughly. I absolutely want the Vintage Knob to have a HUGE RANGE... but I think with the values I have recommended, it will still sound extremely "vintage", and in most cases you would never even want that much variance, and probably run the knob in the 1/4 to 3/4 range. I believe making these changes would improve the "vintage character" throughout the value of the knob... it will give improved character at low values and medium values, and be usable all the way up to 3/4 or fully up.

I have developed VCM sound sets / patch banks for Prophet Rev 2 and DeepMind... For sale here:
https://sellfy.com/sounddesign

For more in depth info about the research I've done over the past few years, and voice component modeling with a variety of different synths, check out the VCM website I created:
http://www.VoiceComponentModeling.com

Also, more articles and info here on the topic of voice variance:
https://www.presetpatch.com/articles/...

And I have many free example patches for a variety of synths here:
https://www.presetpatch.com/user/Crea...

00:00 Intro
00:23 Voice Modeling Background
01:00 My Take on Vintage Knob Implementation
01:53 Benefits of Curated, Stable Variances
02:45 Testing Parameters and Methodology
03:28 Overview of Recommendations
06:24 Analysis: Osc 1, 2 Tuning Variance
09:54 Recommendation: Osc 1, 2 Tuning Variance
13:04 Analysis: Filter Envelope ADR Variance
17:19 Recommendation: Filter Envelope ADR Variance
21:17 Analysis: Filter Cutoff Variance
24:20 Recommendation: Filter Cutoff Variance
25:40 Make Changes in Firmware?
26:45 Other Parameters, Priorities
27:13 Retiring Slop/Drift
27:52 Looking Forward to Future

A couple extra notes here regarding OB-6... Disclaimer: I did these tests on Prophet 6... I have not tested an OB-6, and its possible the value ranges are different on the various instruments. Also worth noting for OB-6 users: Since the OB uses a 2-Pole filter, the extreme dissonance of the cutoff deltas, and large ADR filter variance would be much less evident on the OB, because the filter slope is half as steep. With a 4-Pole filter (P6), you audibly hear the cutoff point much clearer, as there is a steep dropoff (24db/octave). With a 2-Pole, the audible location of the cutoff points is less clear since the dropoff is half as intense.