GENERATORS

Sytrus - Working with the Envelope Editor

The envelope editor is used to adjust the articulation settings of a module: all envelopes, LFO and mapping charts. The envelopes in Sytrus are highly customizable, each envelope segment can consist of an unlimited number of nodes and segments, each with customizable tension (acceleration). The articulator combines the best of multipoint envelopes and simpler ADSR envelopes with special section markers that make ADSR automation possible. Section markers can also be used to create Arpeggios that are also defined in Envelopes.

Common Functionality & Spline Editing

Although there are several types of envelopes and maps in Sytrus, they all share this common functionality:

Enable/Disable Switch

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

Load/Restore & Copy/Paste

Note the placement of the load/restore button in the screenshot above.

• Open state file / Save state file - Open and save envelope states. There are a number of pre-defined state files available.
• Copy state / Paste state - Use to copy and paste envelopes, usually between operators.
• Flip vertically - Invert the current envelope.
• Analyze audio file - Sytrus will emulate the volume envelope of an input sound file. Clicking this option opens a 'browse file' dialog.

Common Settings

• Freeze - Enable this switch to lock the envelope curve to its current setup. This feature is helpful after you finish with the changes to the spline structure of an envelope and want to protect it from accidental edits (it also hides the handles providing a clear view of the shape).
• Step - Enable this option to set the editor in step editing mode - drag in the editor to create a "free hand" curve where a new control point is defined for every step in the timeline. Hold SHIFT key while dragging to draw "pulse" lines (straight vertical/horizontal lines only). Note that each new segment created this way uses the last tension set while adding a segment.
• Snap - Enable this option if you want the control points to snap to the nearest step in the timeline while dragging.
• Slide - Enable this option to preserve the relative distance between a dragged control point and all control points following it (this option is enabled by default).

Curve Editing

Here are several basic operations you can perform to edit the envelope/mapping shape:

• Add a new Control Point - Position your cursor over the line until the add point cursor appears (). Right-click and a new point will be added.
• Reposition a Control Point - You can drag the control points with your left mouse button. Hold SHIFT while dragging to lock vertical position or CTRL to lock horizontal position.
• Delete a Control Point - Right-click a control point and select Delete. Alternatively hold ALT and left-click.
• Change Segment Type - Sytrus offers three types of spline segments to select from. Right-click a control point and you will see three spline type options (the affected segment is the one preceding the control point): Single Curve - the default mode which allows you to create linear, ease in and ease out curves (depending on the tension); Double Curve - allows linear, ease in-out and ease out-in curves (depending on the tension); Hold - creates "hold" or "pulse" curves which are handy for creating abruptly value changes in your envelope.
• Change Segment Tension (Acceleration) - You can drag the tension handle (see the screenshot above) of each spline up/down to change the spline appearance. Right-click the handle to reset to a straight line. Hold CTRL during adjustment to fine tune.

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:

• S (sustain): Marks the end of the decay section and the start of the release section.
• L (loop): Marks the start of a sustain loop section, thus enabling you to define an envelope section to be repeated while a voice is sustaining.
• D (decay): Marks the start of the decay section.
• DL (decay/loop): Combines the function of the D and L markers.

It's not required to use all or any of the provided markers. 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 you're trying to insert the marker at the correct place (a sustain loop start can not be after sustain loop end, for example).

To make a DL marker, simply check both 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) pointless, so they are removed automatically as well (if you remove the sustain loop end marker, a sustain loop start marker would not have a purpose).

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, WS /waveshaper/ in the filter module is also covered below):

ADSR Envelope (ENV)

This is a "classic" ADSR envelope plus the possibility to define a sustain loop section & the power of unlimited spline segments to refine the various envelope sections as you need.

Besides the editable envelope curve, the envelope also provides the regular envelope level controls, so you can lock the curves and still adjust some basic aspects of your envelope. All values are applied relative to the curve defined in the editor:

• Attack (ATT) - Defines the attack length/speed.
• Decay (DEC)- Defines the sustain section length/speed.
• Sustain (SUS) - Defines the sustain section slope ("decay" amount).
• Release (REL) - Defines the release length/speed.
• Tempo - This switch lets you determine whether the envelope length is relative to the project tempo (changes with tempo) or absolute in time.
• Global - Enable this option to use global envelopes. The envelope of all notes (including those already playing) restarts as each new note starts playing (so all notes share the same envelope). This is useful for making perfectly synchronized gated presets and some special effects.

Note: While adjusting one of those properties you can see a preview of the effect of the knob value on the envelope shape. However once you release the mouse key the envelope is restored to its previous view. The knob still has its effect, though it is not reflected in the curve to avoid distortion and to 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, please check the Envelope Sections (ADSR) paragraph above.

Low Frequency Oscillator (OSC)

This unit allows you to vary the controlled property with an LFO. The LFO also includes a full envelope to define its strength in time.

The secondary blue curve you can see behind the envelope is a preview of the LFO "in action" as with the applied envelope, shape speed and settings.

The following knobs are additionally available for this unit:

• Speed (SPD) - Defines the LFO speed.
• Tension (TENS) - Defines the LFO curve "tension" - basically this parameter lets you morph the LFO shape from triangular through sine-like to pulse-like (square) shape.
• Skew (SK) - Defines a balance between the odd/even splines in the LFO visible as shape 'skew'.
• Pulse Width (PW) - Sets the pulse width, i.e. basically the balance between the first and the second half of the LFO phase.
• Tempo - This switch lets you determine whether the envelope/LFO speed is relative to the project tempo (changes with tempo) or absolute in time.
• Global - Normally the LFO envelope is started from the beginning for each voice ("local" LFO) . If this option is enabled, the envelope is "global" and thus stays in the sustain state without restarting for the whole duration of the song.

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

The mapping units let you map the value of the controlled property to the values of another property (keyboard key, velocity etc.).

The mapping is basically a single continuous curve where 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 how the horizontal positions are related to vertical positions, this way mapping the source property to the controlled property.

You can notice a brighter vertical line in the graph - it represents the current value of the source property used for mapping (or the default value, if current is unavailable /such as with velocity/).

The Sytrus graphs cover several mapping sources:

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's own 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 (you can find the X/Y Controller in the main module of Sytrus) to changes of 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 can be useful to simulate a live performance or the slight inaccuracy 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. So the more curve "dots" there are there for a certain vertical position, the greater the chance is this value will be selected by the random generator, thus allowing you to fine tune the behaviour or the random generator and effectively defining the "chances" for certain values to be selected for each voice.

Unison Mapping (UNI)

This mapping is used by the unison feature of Sytrus (see the main module for more information on the unison mode) 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 your sequence. The unison mapping lets you define how the controlled property varies across each of the subvoices inside the unison.

By default the unison uses only its global variation levels (if enabled) as specified in its global settings. But defining a mapping curve in this unit you are given a much greater control over which property, in which module is varied and how exactly it varies.

WaveShaper Mapping (WS)

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