Sytrus - Working with the Envelope Editor

The Envelope Editor may be used to adjust the articulation settings of a module including all envelopes, LFO and mapping charts. Sytrus envelopes are very customizable - each envelope segment can consist of unlimited nodes and segments, each with customizable tension (acceleration). The articulator combines the best of multi-point envelopes and more simple ADSR envelopes with special section markers that allow for ADSR automation. Section markers can also be used to create arpeggios which can also be defined within envelopes.

Common Functionality & Spline Editing

Although there are several different types of envelopes and maps in Sytrus, they all share common functionality, as described below.

Enable/Disable Switch

To use envelope/mapping, you first need to enable it by turning on the LED at the bottom left of the editor (see the screenshot above).

Load/Restore & Copy/Paste

Note the placement of the load/restore button in the screenshot above. NOTE: Not all options appear for all Envelope sources.

Common Settings

Curve Editing

There are several basic operations for editing the envelope/mapping shape:

Envelope Sections (ADSR)

Some of the envelopes/mappings are divided into sections to provide classic ADSR (attack, decay, sustain, release) envelope functionality.

Sytrus uses special section markers (see the screenshot above) to mark the end of a section and the start of the next one. There are few markers available:

It is not necessary to use any or all of the markers provided. Without markers the envelope will be played once as a 'static' definition played once from start to finish for each voice. You can also use certain combinations as needed.

How to Add a Marker:

Right-click the control point where you want to set the section marker. From the menu select the marker you want to add. If the item you want to add is disabled make sure the marker is in the correct place (e.g. a sustain loop start cannot be placed after a sustain loop end).

To make a DL marker, simply check both the Decay and Sustain Loop Start entries in the Right-click menu.

How to Remove a Marker:

Right-click the control point where the marker is placed and uncheck the item representing the marker name. Keep in mind that removing some markers might make another marker/s redundant or cause them to be removed automatically (e.g. if you remove the sustain loop end marker, a sustain loop start marker will become redundant).

Envelope/Mapping Types

There are few types of envelopes/mappings which define the articulation of a specific property: ENV, LFO, KEY M, VEL M, etc. The only exception is WS (WaveShaper) in the filter module (as described below).

ADSR Envelope (ENV)

This is a "classic" ADSR envelope which combines the ability to define a sustain loop section with the power to create unlimited spline segments and refine various envelope sections as needed. Besides the editable envelope curve, the envelope also provides the regular envelope level controls, allowing you to lock the curves and still adjust some basic aspects of your envelope. All values are applied relative to the curve defined in the editor.

NOTE: When adjusting ADSR properties you can preview the effect of the knob value on the envelope shape. However, once the mouse key is released the envelope is restored to its previous view. The knob still has an effect, although it is not reflected in the curve to avoid distortion and make editing easier.

For more information on the available envelope sections (attack, decay, sustain, sustain loop, release) and how to define/remove a section marker, see Envelope Sections (ADSR) above.

Low Frequency Oscillator (LFO)

This unit allows you to vary the controlled property with an LFO. The LFO can also be modulated by its own envelope. The secondary blue curve visible behind the envelope is a preview of the LFO "in action" with the applied envelope, shape speed and settings.

The following additional knobs are available for this unit:

Mappings - Key M, Vel M, Mod X, Mod Y, Rand, Uni

The mappings unit lets you map the value of the controlled property to the values of another property (keyboard key, velocity, etc). Mapping involves the definition of a single continuous curve in which the horizontal direction represents the values of the source property used for mapping - min>max = left>right; and the vertical direction represents the values of the controlled property (articulation target) - min>max = bottom>top. By defining the mapping curve, you define where the horizontal positions are relative to the vertical positions, thus mapping the source property to the controlled property.

Within a Sytrus graph the brighter vertical line represents the current value of the source property used for mapping (or the default value, if current is unavailable /such as with velocity/).

Sytrus graphs allow several different mapping options:

Keyboard Mapping (KEY M)

With keyboard mapping you can define how the controlled property is offset depending on the keyboard key (note) pressed to generate a voice. At the bottom of the graph you can see the keyboard range (the highlighted range matches the range displayed by the integrated Sytrus keyboard).

Velocity Mapping (VEL M)

With this graph you can define how the voice velocity value relates to the controlled property.

Modulation X/Y (MOD X and MOD Y)

These two graphs allow you to map the values of the integrated X/Y controller (in the main module of Sytrus) to changes in the controlled property.

Random Mapping (RAND)

The random mapping lets you define the amount of randomization to the controlled property (one random value per voice is generated). This may be useful for simulating a live performance or the subtle inaccuracies of old analogue synths.

A random floating point number is selected for each voice, in the range of 0% to 100%. The curve lets you define how the random number relates to changes in the controlled property. The more curve "dots" there are for a particular vertical position, the more likely the value will be selected by the random generator, thus allowing you to fine tune the behavior or the random generator and effectively defining the "chances" of certain values being selected for each voice.

Unison Mapping (UNI)

This mapping is used by the unison feature of Sytrus (see the main module for more information) and it has effect only if the unison mode is enabled for the current patch.

The unison mode works by triggering a user-defined number of subvoices with altered properties for each actual voice in the sequence. Unison mapping lets you define how the controlled property varies across each of the sub-voices inside the unison.

By default the unison uses only its global variation levels (if enabled), as specified in the global settings. By defining a mapping curve in this unit you can have much greater control over the type and amount of variation of both the property and the module.

WaveShaper Mapping (WS)

This is the only articulated property defined by a single mapping and is available in each of the filter modules. The curve defines how the signal is distorted by the WaveShaper features in the filter modules, i.e. the original input levels and how they relate to the processed output levels.