OP-1 : Master the dsynth engine

Hi, I open a thread to master the dsynth engine which is a multi envelope dual oscillator synth.

Thanks for your remark/feedback.

1 - Understand the concept of multi envelope :
Envelope crossfader parameter work with decay parameter to define the final envelope for each oscillator.

  • Envelope crossfader parameter define for each oscillator the envelope type in decay section and the envelope amplitude (not envelope volume) → there is no envelope modulation if crossfader parameter is a line (the OSC sound is continuous)
  • Note : grey line is OSC 1 and blue line is OSC 2 (I thought the opposite)

I’ll add pictures when I can …

  • dsynth crossfader parameter :
    OP-1 dsynth crossfader
  • Envelope types corresponding to crossfader “down-up” configuration :

OP-1 dsynth crossfader down

  • Envelope types corresponding to crossfader “up-down” configuration :

OP-1 dsynth crossfader up


ex. below allow to hear OSC 1 alone, then OSC 1 + 2, then OSC 2 alone

OP-1 dsynth envelop 1

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Iinteresting envelope with double attack (echo effect with max value) :

dsynth double attack


Very informative, thank you for shedding some light on this engine!

For the next topic about cross modulation and filter cutoff parameters (graduations in number of notches) :
OP-1 Filter


Summary of multi envelopes concept (for the patch sheet in progress)
Enveloppe recap


This is such a valuable thread, :pray: thanks again!

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I’m really excited to find out if you can shed some light on the mode parameter. Great work so far

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2 - Understand the concept about dual oscillator
(I’m not a specialist. I’m a simple OP-1 explorer)
Before talking about cross modulation, let’s talk about the “frequency” parameter of OSC 2.
The mix of 2 waves with d-synth makes it possible to obtain the analog synthesizer effects.

I don’t know why TE put an M and the values 0,1 because in fact this parameter determines the OSC 2 pitch from 0 to -4 octaves compared to OSC1 pitch.

OP-1 - OSC2 freq

Here are the values that I have chosen to make a playable sound (in notch starting from the octave 0) :

  • 0 - OSC1 and OSC2 are in the same octave : sound clean
  • 1 : sound is bigger + phaser effect → audio link
  • 18 : sub-oscillator effect → audio link
  • 29 - OSC2 is 1 octave lower than OSC1 : sound clean, lower + phaser effect → audio link
  • 37 : sub-oscillator effect → audio link
  • 42 : sound is bigger + phaser effect → audio link
  • 50 - OSC2 is 2 octaves lower than OSC1 : sound clean + light sub-oscillator effect → audio link
  • 55 : sub-oscillator effect → audio link

To try these, use (global) octave shift = -1 with parameter below :

Note : audio examples are without FX.


About filter parameter :

  • from 0 to 36 : low sound (filters high frequencies)
  • 36 : balance point (in my opinion)
  • from 36 to 90 : high sound (filters low frequencies)
  • over 90 : sound becomes inaudible

OP-1 - Filter parameter

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I added audio examples on the audiofanzine site


Extremely clear illustrations. Thank yoy

I think the filter itself is just a resonant band-pass with wide Q-value. The setting at 11 o’clock simply corresponds to frequencies oscillators normally generate around 0 octave. However, its knob value seems to be also tied to something else.

D-Synth is crazy. TE should post some definitive info about about it.


you are right, especially for the OP-1 field :

  • the env crossfader parameter has changed compared to the original OP-1
    OP-1-vs field
    I redo my work to find the corresponding envelopes … :face_with_thermometer:
  • tapping an encoder allows a very interesting fine adjustment especially for frequency OSC2 parameter
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Hi, here are the parameters with the corresponding global OSC enveloppes on OP-1 field


Totally missed this. This is a very good feature. Might not seem like it, but some values of the mod parameter (red) make the whole DSynth sound totally different and they weren’t accessible before except with LFOs.

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