Skip to main content
Please log in to rate Already rated

PSDN CV Envelope Generator

Nonlinear CV Envelopes

Alien Seed Tech

  • • Dual Nonlinear CV Envelope Generator
  • • Indy or Linked Envelopes with Complex Curving
  • • Plenty of CV I/O

Video clips

Audio examples

The free 4U 2.0 upgrade is nearing completion. Serious apologies!

Version 2.0 will add 8+8/16 channel polyphony, a 2d display for the envelopes, tons of CV connections, custom meter/display colors, many more controls, etc. See the new videos (the last 4) for a look at it and the KRON in action. The very last video is the most recent. Note though that it is now 4U, not 3U, adding user controls, a patch browser, even more options, etc.

The PSDN is a curved dual CV envelope generator with tons of options. The envelopes can be combined or used separately, one launching from the other, triggering additional PSDNs, etc. It's versatile! And it will be even more so when version 2.0 comes out.

Product details

Get the manual here.

Version 1.03 Updates:

  • fixed back panel output toggle bugs
  • brightened red/green knobs

Version 1.02 Updates:

  • new "smooth batches" knobs average the output over time
  • fixed 0% sustain link problems
  • renamed "poly" menu as "retrigger"
  • updated manual

On the front panel, each envelope has:

  • 6 faders (ADSR and 2 delays)
  • lengths in seconds or synced (instant to 31.5 seconds or instant to 128/4 with 38 sync lengths)
  • loop and invert toggles
  • a level knob
  • a common mathematical curve function
  • a common shape that can be applied to individual ramps
  • a curve amount knob for each A, D, and R ramp
  • a linear midpoint knob for each A, D, and R ramp
  • an overall vertical/horizontal midpoints toggle
  • green active lamps for each stage, showing the currently active stage
  • red/yellow/orange link lamps for each stage, showing the start and end points of the front and back panel links

Other front panel features:

  • device on/off, graphics on/off and FPS controls
  • +/- gate velocity to envelope level
  • a retrigger menu (hold, mono, or poly) that controls when note/gate hits re-trigger the envelope
  • a link type menu (no link, simple adding, normalized adding, and linked but not adding)
  • start and end link point menus that also appear as red lamps under the stages
  • link active and link error lamps
  • +/- link output to level scaling (for adding the 2nd to the 1st and adding external signals)
  • 4 mod entries that can wire up anything to anything else, including multiple sources and destinations and entries for adding signals to the envelopes
  • a help popup menu

On the back panel, each envelope has:

  • 2 gate inputs
  • 7 gate outputs, 1 for each stage (with an overall level knob and an optional length knob on the final done stage)
  • 4 envelope outputs (which have overlapping bipolar and invert-toggled sections)

Other back panel features:

  • the 2nd envelope has rewire toggles so that its gate inputs, stage gate outputs, and envelope outputs can be used for the 1st or linked envelope instead.
  • 8 CV inputs for the mods
  • an extra link that can be used on either envelope in order to drive other devices.
  • 4 extra outputs that can be wired up with the mods
  • a direction toggle for the decay and release shapes
  • a help popup menu


  • All menu entries have an abbreviation and then a description. The abbreviation is seen when it's selected or scrolled through via the scroll buttons. Both abbreviations and descriptions are seen when clicking on and viewing the whole menu. The formatting is the best I could do using spaces (which is all I could use), but certain OSes / screen fonts make it look worse. Apologies! That may change with a future SDK version.
  • The Retrigger menu retriggers the envelopes according to mono/poly notes. This device only produces one envelope at a time for each of its envelope outputs (x 2), ie. it is normal CV output data.



Released: 2015-12-02
Version: 1.0.3