Envelopes#

The Cosmo PD-101 uses 8-step step-function envelopes — a distinctive feature inherited from the Casio CZ-101. Unlike traditional ADSR envelopes, each envelope consists of 8 discrete steps, each with its own level and rate (duration). This gives you precise, complex control over how a parameter evolves over time.

Envelope Types#

Each oscillator line has three independent envelopes:

Envelope	Controls	Parameter ID
DCO Envelope	Pitch (frequency) of the oscillator	dcoEnv
DCW Envelope	Warp depth — how much the algorithm distorts the phase	dcwEnv
DCA Envelope	Amplitude (volume) of the oscillator	dcaEnv

There is also a separate Mod Envelope (ADSR) used for modulation routing (see Modulation).

Step Envelope Structure#

Each envelope has:

• 8 steps (numbered 1–8)
• Each step has a Level (0–127) and a Rate (0–127)
• A Sustain Step — which step to hold on while a key is pressed
• A Loop toggle — whether the envelope restarts from step 1 after reaching step 8
• A Step Count — how many of the 8 steps are active

Understanding Level and Rate#

Concept	Range	Meaning
Level	0 – 127	The output value of this step. For DCO, this is pitch offset (in semitones from base). For DCW, it's warp depth. For DCA, it's amplitude.
Rate	0 – 127	How long this step takes to reach the next level. Higher = slower.

Think of it like an ADSR, but with 8 points instead of 4:

The 8 Steps in Practice#

Classic Attack–Decay–Sustain–Release (ADSR) Approximation#

To recreate a traditional ADSR:

Step	Level	Rate	Purpose
1	0	Fast	Attack start
2	127	Fast	Attack peak
3	127	Medium	Decay start
4	80	Medium	Decay to sustain
5	80	–	Sustain step (held while key is down)
6	80	–
7	80	–
8	80	–

With loop off, the envelope continues through steps 6–8 even during sustain. With loop on, it cycles back to step 1, creating a LFO-like effect.

Creating a "Bounce" Envelope#

Step	Level	Rate	Purpose
1	0	10	Quick attack
2	100	20	Overshoot
3	40	15	Drop back
4	80	10	Rise again
5	60	–	Sustain
6–8	60	–	Hold

This creates a pitch envelope that "bounces" before settling — great for pluck sounds.

Editing Envelopes#

In the UI, the Step Envelope Editor panel displays all three envelopes for the selected line:

• Click on a step to select it
• Drag vertically to adjust level
• Drag horizontally or use the numeric field to adjust rate
• Click the "S" button on a step to set it as the sustain point
• Toggle the loop icon to enable/disable looping

DCO Envelope — Pitch#

The DCO envelope controls pitch offset in semitones:

• Level 0 = base pitch (no offset)
• Level 127 = +12 semitones (one octave up)
• Negative values are not supported directly — use the global pitch controls or detune instead

Tip: Use the DCO envelope for pitch sweeps, dive bombs, and expressive lead sounds.

DCW Envelope — Waveshape#

The DCW envelope controls how much the phase distortion algorithm affects the sound:

• Level 0 = no distortion (raw base waveform)
• Level 127 = maximum distortion

This is the most expressive envelope — it morphs the timbre over time. With Fold algorithm, for example:

• DCW 0 = clean sine
• DCW 64 = subtle harmonic richness
• DCW 127 = aggressive, chaotic folding

DCA Envelope — Amplitude#

The DCA envelope controls volume over time — functionally similar to a traditional amplitude envelope:

• Level 0 = silence
• Level 127 = maximum volume

Pop Suppression#

When switching between notes, the engine applies automatic pop suppression — a short fade at transition boundaries to prevent clicks and pops. This is handled transparently and requires no user configuration.

Envelope Tips and Tricks#

Technique	Steps to Set Up
Long pad, slow attack	Step 1: L=0, R=60 → Step 2: L=100, R=80 → Sustain on step 2, loop off
Percussive pluck	Step 1: L=0, R=2 → Step 2: L=127, R=5 → Sustain on step 2, loop off → Short DCA release
Arpeggiated pitch	Step 1–8: alternating L=0 and L=30, loop on, moderate rates
Vibrato via looping DCO	Step 1: L=120, R=30 → Step 2: L=132, R=30 → Loop on, sustain on step 1

Next: Modulation → | Previous: Overview → | Algorithms →