FXpansion STROBE-2 Operation Guide

Strobe2

Strobe22

Operation Manual

1 Strobe2 Introduction

................................................................................................................................... 6Interface overview1.1

................................................................................................................................... 8Adjusting sliders and rotary controls1.2

................................................................................................................................... 9Adjusting TransMod modulation1.3

................................................................................................................................... 12Other controls and indicators1.4

................................................................................................................................... 14Unit and Snapping modes1.5

................................................................................................................................... 15Locks1.6

................................................................................................................................... 16Parameter context menu1.7

2 Browsing presets

3 Synthesis Engine

................................................................................................................................... 24Oscillator section3.1

................................................................................................................................... 28Filter (V.C.F.) section3.2

................................................................................................................................... 30Amp (V.C.A.) section3.3

4 Global Synth Controls

................................................................................................................................... 32Polyphony: Voice and Unison settings4.1

................................................................................................................................... 33Keyboard Input, Glide and Retrigger controls4.2

................................................................................................................................... 35MIDI CC Learn mode4.3

5 Modulation

................................................................................................................................... 39Using TransMod modulation5.1

................................................................................................................................... 44Modulator gating/triggering5.2

................................................................................................................................... 46Dual LFO5.3

................................................................................................................................... 49Amp and Mod Envelopes5.4

................................................................................................................................... 51Ramp5.5

................................................................................................................................... 53Keytracking5.6

................................................................................................................................... 55Velocity and Performance controllers5.7

................................................................................................................................... 57Monophonic sources5.8

................................................................................................................................... 58Voice and Unison sources5.9

................................................................................................................................... 60Curve processors5.10

................................................................................................................................... 62Euclid processor5.11

................................................................................................................................... 64Random sources5.12

................................................................................................................................... 65Gate/Trigger sources5.13

6 Arpeggiator page

7 Effects page

................................................................................................................................... 71EQ7.1

................................................................................................................................... 73Dynamics7.2

................................................................................................................................... 76Delay and Reverb7.3

................................................................................................................................... 80Modulation FX7.4

................................................................................................................................... 86Distortion FX7.5

8 Quick-presets, Morphing and Randomizing

................................................................................................................................... 92Morphing and Freezing8.1

................................................................................................................................... 95Randomizer8.2

9 Preferences

10 V.C.F. Mode responses

Strobe24

1 Strobe2 Introduction

Introduction

Strobe2 is a performance synthesizer, designed to be easy to program so that you can concentrate on playing and recording great-sounding music! A single-oscillator synth with osc-stacking, sub-osc and osc sync, it also features a versatile multimode filter, dual LFO, ramp generator and two envelopes.

Strobe2 is designed for powerful analogue-style basses, leads, pads and polysynth sounds but its modulation and effects functionality make it great for experimentation and discovering new kinds of timbres.

While being inspired by relatively simple monosynths such as the Roland SH series (especially the SH09 and SH-101), Oberheim OB-1 and SCI Pro-One, Strobe2 is not an exact model of any particular synth and features hugely improved possibilities over its vintage inspirations: it has been designed to take the performance synthesizer into a new dimension.

Strobe2 highlights

Osc section

At the heart of Strobe2 is a single 'super-oscillator' which allows many of the timbres possible with multiple-oscillator architecture but with far fewer controls, enabling fast programming.

• Each waveform in each osc sub-section: main oscillator, sub oscillator and noise generator - can be heard in parallel using mixer faders to blend between them.

• It features built-in hard-sync and osc stacking functions for complex harmonics, detuning effects and chord sounds.

• Additionally, all 3 osc sub-sections each feature a polyphonic keyboard-tracking Tone control for adjusting spectral balance before the more radical sculpting offered by the V.C.F. section.

V.C.F. (Voltage-controller Filter) section

The detailed filter model features a large variety of modes, leading to a wide range of potential timbres. It also includes realistic overdrive of the circuit, further increasing the tonal range.

V.C.A. (Voltage-controlled Amplifier) section

Strobe's Amp section features a model of an 'O.T.A.' type filter circuit core which produces realistic overdrive and saturation - a very important part of the sound of vintage synths. This section also contains the Analogue control which introduces noise and hum into Strobe2's control circuitry - this can result in musically organic behaviour with realistic hardware noise.

Strobe2 Introduction 5

Simple direct modulation

Strobe2 has been designed so that its main parameters can be modulated using dedicated controls - the Osc Pitch, Pulse Width and Filter Cutoff can be directly modulated by the keyboard, LFO or mod envelope using dedicated faders. These modulation techniques are able to create many classic analogue-style sounds.

Advanced but intuitive TransMod modulation

Strobe2 also features the TransMod modulation system which goes far beyond these dedicated modulation routings and greatly expands its sound design and performance potential. TransMod modulation offers a huge range of monophonic and polyphonic modulation sources which can be routed to almost any synthesis parameter.

Polyphony and unison

Unlike the monosynths which inspired its design, Strobe2 is capable of polyphony - you can set up as many voices as your CPU can handle and also define a number of unison voices. For example, with 8 voices and 2 unison voices, the result is 4-note polyphony with each note comprising 2 unison voices.

Using the TransMod modulation system, it is possible to vary almost any synthesis parameter for each unison voice - not just the simple unison detuning available on vintage polysynths.

Arpeggiator page

Strobe2's Arpeggiator page turns MIDI note input into rhythmic arpeggio sequences. It also provides a parallel modulation Step Sequencer for modulating parameters via the TransMod system. The Arpeggiator and Step Sequencer can interact in a number of ways.

Effects page

Finally, Strobe2 provides a built-in effects section - 6 instances from 28 available built-in FX devices may be loaded and even modulated via the TransMod system.

Other highlights

Strobe2 also includes a preset switching and morphing system as well as a Randomizer which makes it easy to come up with new sounds.

Strobe26

Browser

The Browser provides 1-click access to Strobe2's library of presets. It also saves and loads presets created or modified by the user.

The Browser's visibility can be toggled by clicking the Browser button above the Browser area.

Just above the Browser are buttons which display the following menus:

Preferences menu : contains a number of additional Strobe2 settings

Locks menu : provides the ability to lock groups of controls from being affected by

editing, preset-switching, morphing and randomizing

Synthesis engine

The Synth page contains the synthesis engine parameters for Strobe2 - all parts of the audio path before the effects section - as well as the Visualizer Scope.

Modulation

The Synth page also includes the Dual LFO, Ramp and Envelopes.

• Arpeggiator page

This page contains Strobe2's built-in Arpeggiator as well as a parallel modulation Step Sequencer which can be used with the TransMod system and also interact with the Arpeggiator.

• Effects page

The Effects page contains 2 FX chains (FX A and FX B), each of which features 3 slots in which to insert FX devices. Strobe2 provides 28 built-in FX devices of various kinds.

1.1 Interface overview

Interface overview

Main Editing area

The main editing area is switchable between 3 different pages:

• Synth page

The Scope area can be switched to display the Euclid, Curve and KeyZone modulation processor editors.

Strobe2 Introduction 7

This section of the interface is always visible, even when viewing the Arpeggiator or Effects pages.

The 16 TransMod modulation slots are central to Strobe2's advanced but intuitive TransMod modulation system.

This section allows 8 presets to be loaded into the available Quickpreset slots for fast access and morphing functions which offer radical timbral shifting. Morphing can also be 'frozen' to create new interesting sounds, as can this section's Randomizer functions.

Global synth controls

These settings relate to the way that Strobe2 responds to being played - including polyphony, unison, note priority, master tuning, pitch bend and glide functionality. This section also contains the CC LRN button for assigning MIDI CCs to controls.

This area also contains the P1 (Perf1) and P2 (Perf2) performance controls which provide variation with real-time performance controller input. These must be assigned to available hardware MIDI CC controllers using the MIDI CC Learn mode function.

TransMod modulation slots

Although Strobe2 already features dedicated Keyboard, LFO and Envelope modulation amount faders for oscillator pitch, pulse width and filter cutoff, the TransMod modulation system goes far beyond these capabilities. Each of the 16 TransMod slots can modulate virtually all Strobe2 parameters from a single modulation source, optionally scaled (multiplied) by another modulation source.

Quick-presets, morphing, Freeze and Randomizer controls

Strobe28

Move the mouse above the slider cap. Notice that it is highlighted. Now either:

• use the mousewheel or trackpad scroll function

• or click and drag the slider cap up/down.

The new value is shown in real time on the tooltip which appears.

• It is also possible to double-click the slider cap, type a new value in the box which appears and press ENTER or RETURN.

Move the mouse above the rotary control. Notice that it is highlighted. Now either:

• use the mousewheel or trackpad scroll function

• or click and drag the control up/down. The new value is shown in real time on the

tooltip which appears.

• It is also possible to double-click the control, type a new value in the box which appears and press ENTER or RETURN.

1.2 Adjusting sliders and rotary controls

Adjusting initial values of parameters (No TransMod slot selected)

Sliders

Rotary pots

Fine control over parameters

Hold down the SHIFT key while adjusting a control for finer resolution.

1.3 Adjusting TransMod modulation

• click on the upper part of the slot To select a slot and display its TransMod source menu.

• click on the lower part of the slot to select a slot and display its TransMod scalar menu.

• to select a slot without displaying any menus, click the central part of the slot.

• to deselect all TransMod slots to work only on initial parameter values as shown in the last section, click its central part again.

Introduction to TransMod modulation

The TransMod system provides an intuitive but very deep modulation system for Strobe2's parameters. See chapter 5 for a full guide to understanding the TransMod system.

Selecting TransMod slots

To begin using TransMod modulation, one of the 16 TransMod slots must first be selected. Each TransMod slot can be assigned to a modulation source which is chosen from an extensive list of monophonic (applied to all playing notes) and polyphonic (applied to each note individually) modulation sources.

Strobe2 Introduction 9

The vast range of TransMod modulation sources (which can also be used as scalars, which scale or multiply a slot's modulation source) are described later in this manual.

When a TransMod slot is selected, TransMod-enabled parameters in Strobe2 display and allow editing for modulation depths on parameters. The vast majority of parameters in Strobe2's Synth, Effects and Arpeggiator pages can be modulated. However, some controls such as buttons and certain other parameters cannot be modulated.

Strobe210

Position the mouse within the slider but above or below the slider cap. Notice that the entire slider is highlighted. Now either:

• use the mousewheel or trackpad scroll function

• or click and drag up/ down.

The initial value and new modulation value are both shown in real time on the tooltip which appears.

• It is also possible to double-click above/below the slider cap, type a new value in the box which appears and press ENTER or RETURN.

Move the mouse above the slider cap - notice it is highlighted.

• Use the mousewheel to adjust the initial value - the modulation depth is preserved.

• or click and drag up/ down.

The initial value is shown in real time on the tooltip which appears.

• Alternatively, double-click and type a new value.

• It is also possible to hold down the ALT key while clicking and dragging the slider cap (or scrolling with the mousewheel/trackpad) to adjust the initial value without preserving the modulation depth.

Adjusting TransMod modulation depths: Sliders

When a TransMod slot is selected, Strobe2's slider-type controls can be manipulated in the following ways:

Creating modulation on sliders

Adjusting the initial value with or without modulation

Strobe2 Introduction 11

Move the mouse above the outer ring of the rotary control. Notice the highlighting around the control. Now either:

• use the mousewheel or trackpad scroll

• or click and drag up/down. The initial value and new modulation value

are both shown in real time on the tooltip which appears.

• It is also possible to double-click in the outer ring, type a new value in the box which appears and press ENTER/RETURN.

Move the mouse above the main part of the rotary control notice it is highlighted.

• Use the mousewheel to adjust the initial value - the modulation depth is preserved.

• Or click and drag up/down. The initial value is shown in real

time on the tooltip which appears.

• Alternatively, double-click and type a new value.

• It is also possible to hold down ALT while clicking and dragging the main part of the rotary control (or scrolling with the mousewheel/trackpad) to adjust the initial value without preserving the modulation.

Adjusting TransMod modulation depths: Rotary controls

Creating modulation on rotary controls

Adjusting the initial value with or without modulation

Strobe212

• Click & drag: click the rotary selector and drag up/down.

• Use the drop-down menu: click on the display that shows the current setting and select the desired setting from the drop-down menu that appears.

Click on the display that shows the current setting and select the desired setting from the drop-down menu that appears.

• Click & drag: click the value and drag it up/down.

• Double-click & type: double-click the value, type a new one and press ENTER/RETURN.

1.4 Other controls and indicators

Rotary selectors and drop-down menus

Other drop-down menus

Numerical text-boxes

There are two ways to adjust these controls:

Strobe2 Introduction 13

Buttons are generally 'toggle' type buttons – click to activate, click again to deactivate. Buttons light up when activated.

Some 'radio button'-style controls also exist, such as the sub-oscillator Octave buttons.

Strobe2 contains some indicator LEDs such as those at the upperright of modulators such as the LFO. These indicators represent the current state of the modulator's output in real-time.

Buttons

Context menus

Many areas of the interface and individual controls within Strobe2 feature a context-menu which is invoked by a right-click (or whichever methods are used for a secondary click on the system, such as a 2-finger tap on a Mac trackpad).

One example is the Parameter context menu which is covered later in this chapter while context menus for various other parts of the Strobe2 interface are mentioned in the relevant parts of this manual.

Indicator LEDs

Strobe214

Controls related to tuning oscillator pitch or filter cutoff frequency offer 4 distinct modes of operation which are accessed via the parameter context menu.

These controls include:

• The Oscillator's 'coarse' Pitch and Sync controls

• The modulation amount sliders for the Master Pitch from keytracking, LFO and Mod Envelope

• The Filter's Cutoff parameter

• The modulation amount sliders for the Cutoff from keytracking, LFO and Mod Envelope

The Just and Harmonic modes are based on perfect pitch ratios as units, rather than absolute frequency settings.

1.5 Unit and Snapping modes

Snapping and Unit modes

These modes persist independently for each control. Note that the Fine oscillator pitch and Detune controls are not affected by snapping modes, which are designed purely for tuning the main oscillator and filter pitch (the latter being especially useful when using self-oscillation at high resonance).

Off

In the Off mode, all snapping is deactivated - the control is set in semitones but does not snap to whole semitones.

Just

Just mode uses perfect pitch ratios as units rather than imperfect, equal-tempered pitch. In this mode, pitch or filter cutoff controls are set in harmonics (Hm). There is no snapping to whole harmonics.

Harmonic

The Harmonic mode is similar to Just, except that additional snapping to whole harmonics occurs (although SHIFT can be held down for fine control).

Equal

In Equal mode controls are set in equal-tempered tuning in semitones and snapping to whole semitones occurs (although SHIFT can be held down for fine control).

1.6 Locks

Strobe2's Locks allow various parts of the state of Strobe2 to remain unaffected when loading new presets. Locks are also very useful when using Quick-preset morphing in situations where very abrupt transitions or clicks may not be desirable.

• Please note that when using Locks, presets may sound very different to how they are intended to sound!

Any currently locked parameters are highlighted in red. Click the Locks button above the Browser area to display a

menu showing the various Locks that can be activated or deactivated:

Clear all locks

This function removes all previously activated Locks.

Individual controls can be locked using the Parameter context menu right-click on a control to display this menu, then use the Lock function.

Locked parameters are highlighted in red.

Locks menu

Synth engine, mod assignments & settings

All synth parameters and modulation depths, TransMod slot source and scalar assignments and the following additional controls are locked:

• Voices

• Unison

• Bend Up/Bend Down

Strobe2 Introduction 15

Mod source assignments

TransMod slot source and scalar assignments are locked.

Polyphony

The Voices and Unison settings are locked.

Synth parameters

All synth parameters and modulation depths are locked.

Arpeggiator

The content of the Arpeggiator/Sequencer page is locked.

FX unit A (slots 1-3)

The content of the Effects page's FX A chain is locked.

FX unit B (slots 4-6)

The content of the Effects page's FX B chain is locked.

Locking individual controls

Strobe216

Select TransMod

This sub-menu provides an alternative means of selecting a TransMod modulation slot without having to move the mouse away from a control in the midst of sound design: right-click the parameter, select the desired TransMod slot from the menu and then create TransMod modulation depths on the control (and on any other controls) as desired.

Snap

The Snap sub-menu is available for Oscillator Pitch, Sync and Filter Cutoff parameters and specifies the current Unit/ Snapping modes.

Reset Param

This function sets the parameter to its default value.

Clear Param Mod

Use this function to clear any modulation depth that exists for the parameter from the current TransMod slot.

1.7 Parameter context menu

This menu can be invoked with a right-click (or other secondary click) on a parameter or control in Strobe2.

Clear Param All Mod

This function clears any modulation depths that exist for the parameter from all TransMod slots.

Lock

When activated, the Lock function protects the parameter from any changes if a new preset is loaded from the Browser or if a new Quick-preset is selected. This can be very useful for controls which produce abrupt changes or clicks when morphing to a new preset with the Quick-preset controls. Entire sections of parameters can also be locked using the Lock menu.

Clear MIDI Learn

Use the Clear MIDI Learn function to unassign the parameter from any MIDI Learn mapping.

2 Browsing presets

Strobe2's Browser provides quick access to all factory and user presets. It also provides several additional functions for managing and searching for presets.

Show/hide Browser

The Browser can be shown or hidden as needed. To display the Browser if it is not currently visible, click the BROWSER button in the upper-left part of the Strobe2 interface. To hide the Browser if it is visible, click the BROWSER button again.

Loading and saving Presets

Preset listing

The main part of the Browser area shows the list of available presets. By default all factory-supplied and user-created presets are shown although the list can be narrowed down using the Browser's various filtering and search functions.

• Click any preset in the list to load it.

• To revert to the previous state of Strobe2 before loading the preset, click the Cancel button which appears when a preset is modified (or after the initial state of Strobe2 has been modified).

Previous / Next

Cycle through the available presets sequentially using the Previous and Next buttons.

It is also possible to cycle through presets using keyboard cursor-key shortcuts. Note that some DAW/host applications may intercept keyboard input meaning these cannot be used.

↑ Previous preset ↓ Next preset

Cancel

The Cancel button returns to the state of Strobe2 before the last preset was loaded.

Save As

Click the Save As button to name and save the current state of Strobe2 as a preset. The saved preset is placed in the user presets location.

Quick-preset slots

When a preset is loaded from the Browser, it is loaded into the current Quick-preset slot (of which there are 8 available). These slots are explained in the next chapter.

Browsing presets 17

Import

The Import function can load a preset from any location and optionally add it to Strobe's preset database. This may be more convenient than manually copying the preset to the required folder.

Strobe218

The Sorting drop-down menu to the right of the Search box allows the preset listing to be listed by Type, by Name or by the Date it was last saved.

Sorting by Date can be very useful as the most recently saved presets are shown at the top of the list.

Type

The Type drop-down menu allows the preset list to be filtered to show only 1 of the available preset types. Select (None) for the filter to show all preset types. The following preset types are available:

• (None)

• Arpeggiated

• Bass

• Lead

• Special FX

• Strings

• Texture

• Keys

• Synth

• Chord

• Pluck

• Organ

• Drum

Searching, Sorting and Filtering

The Browser contains a number of additional features for searching or filtering the available presets to find the right sound faster.

Double-click the Search box and enter one or more terms to show only presets whose names match the search term criteria.

Sorting

Filters

The Browser's Filters provide drop-down menus which allow filtering of the preset list according to various criteria.

Browsing presets 19

Library

The Library filter allows either Factory or User presets to be exclusively visible. To show both Factory and User presets in the list, select (None) for the filter.

Artist

The Artist filter allows presets by a single preset designer to be seen. To show presets by all preset designers, select (None) for the filter.

• To mark a preset as a Favourite, activate the

Favourite button to the right of the preset name in the preset list by clicking it.

• Alternatively, use the Add preset to Favourites function in

the Browser context menu (rightclick on a preset to display this menu).

• Activating the Favourites button displays only presets which have been previously marked as Favourites.

Right-click on any preset in the preset list to display the Browser context menu.

Add preset to Favourites Remove preset from Favourites

These functions are described above.

Export preset...

This function exports the preset to any location on disk. This is useful for sharing a preset without having to navigate to the relevant location on disk to find it.

Other controls

The following buttons toggle between 2 distinct preset views. These views can be combined with search and filter criteria.

Legacy

Activating the Legacy button displays only legacy Strobe v1 presets, if DCAM Synth Squad is/was present on the system on which Strobe2 is installed. Deactivate the button to show only Strobe2 presets.

Favourites

To remove the Favourite status for a preset, deactivate the by clicking it again or use the Remove preset from Favourites function in the Browser context menu.

Browser context menu

Reveal in Finder... (Mac) Reveal in Explorer... (Windows)

This function opens a system file window to show the factory or user folder which contains the preset.

Hide preset Unhide preset

The Browser provides the ability to hide presets, which can be considered as a counterpart to the Favourites system described above.

Strobe220

To view all currently hidden presets, right-click the Favourites button and use the Show Hidden function on the menu that appears.

Right-click on any hidden preset and use the Unhide preset function.

To hide a preset from the preset list, use the Hide preset function on the Browser context menu. Hidden presets are not deleted - they can be viewed and unhidden.

Factory and User preset locations

• Factory presets are stored within the following locations:

Mac OSX: /Library/Application Support/FXpansion/Strobe2/Presets Windows: C:\Program Files (x86)\FXpansion\Strobe2\Presets

• User presets are stored within the following locations:

Mac OSX: /Users/<your username>/Documents/FXpansion/Strobe2/Presets Windows: C:\Users\[Username]\Documents\FXpansion\Strobe2\Presets

Sub-folders within the factory and user preset folders are used as Artist names for the presets within them - use the Artist filter to show only the presets within any sub-folder.

3 Synthesis Engine

This chapter describes Strobe2's synthesis sections:

Oscillator Section

Strobe2's Oscillator can be considered as a 'super-oscillator' designed to produce a wide variety of rich oscillator timbres to feed into the Filter section for sculpting. It contains several sub-sections, each of which can be switched on or off via their Power buttons.

Main Oscillator

• The Pitch and Fine controls set the oscillator tuning

• The levels of the main oscillator waveforms are set with the Saw and Sqr (Square) faders

• The Square waveform features control over its pulse width with the PWM parameter

• Faders are provided for setting the amount of direct Pitch and PWM modulation from the Keyboard, LFO and Mod Envelope

• The Sync control increases the pitch of the Main oscillator while forcing it to synchronize to the Master Pitch set by the Pitch and Fine controls, leading to classic 'hard sync' sounds with added harmonic content

• The Stack/Detune functions provide classic detuned osc and 'super-saw' sounds and can even produce chords

• The Reset (Phase Reset) function allows exactly repeatable osc tones, especially useful for bass sounds

• The Cents button sets the detuning mode - with the button deactivated, detuning functions occur after keyboard scaling has been applied, leading to uniform 'beating rates' across the keyboard

Synthesis Engine 21

Sub Oscillator

The Sub Oscillator is intended to provide a solid low-end foundation for sounds.

• With the Link button deactivated, the Sub-osc is not affected by the Main oscillator's Stack, Detune or Sync functions

• A variety of waveform faders are available, with each capable of being tuned 0, 1, 2 or 3 octaves lower than the Main oscillator Pitch

• The Square waveform features control over PWM

• All Sub-osc waveforms are affected by the Shape control which applies a waveshaping function for more complex harmonics in the output

Noise generator

The Oscillator section is completed with a white noise source - the Noise fader sets its level in the Oscillator mix.

Tone controls

Each of the above 3 sections contains its own Tone control - this is a keyboard-tracking EQ function which is useful for emphasizing or de-emphasizing part of the frequency range before the more radical tonal sculpting provided by the Filter section. Altering the spectral balance in this way can affect how the subsequent filter's resonance behaves over the frequency range, changing the character of filter sweeps.

Strobe222

The Scope area performs a number of functions in Strobe2. By default (with the SCOPE button activated as shown on the left),

this mode performs 2 functions:

1. It displays the Strobe2 logo graphic and a level meter representing the final audio output.

2. When the mouse is moved above or used to adjust certain controls, the Scope area switches to the Visualizer display.

The Visualizer provides a context-sensitive graphical representation of various parts of the Strobe2 synthesis engine. Note that it should not be regarded as an oscilloscope, but rather as an aid to visualising each part of the synth.

V.C.F. (Voltage Controlled Filter) Section

The V.C.F. section represents the 'subtractive' part of the term 'subtractive synthesis' - it subtracts parts of the frequency spectrum from the oscillator signal.

• Strobe2's filter model actually utilizes 'pole-mixing' techniques such as those used in the Oberheim Xpander/Matrix 12 synthesizers to create a huge range of unusual filtering responses, accessible via the Mode control

• The filter's Drive function allows a large amount of tonal variation and is gain-compensated - as it is increased, the output level of the filter is reduced in order to keep levels constant at varying Drive settings

• Faders are provided for setting the amount of direct filter Cutoff modulation from the Keyboard, LFO and Mod Envelope.

V.C.A. (Voltage Controlled Amplifier) Section

A synthesizer's V.C.A. performs the task of 'articulating' the amplitude of each synth voice. The oscillator is always running internally - the V.C.A. uses a control signal from an envelope to shape the amplitude (or 'loudness') of each voice when notes are played.

• Strobe2's V.C.A. is always affected by its Amp Envelope.

• The V.C.A. circuit model provides a saturating overdrive effect at higher settings of the Amp control. Reduce the Level control to compensate for the gain increase - otherwise the output may clip.

• For cleaner sounds, reduce the Amp control and increase the Level control

• The Analogue control introduces noise and mains hum within Strobe2's control circuitry, resulting in the synth reacting with a more noisy and organic character

Visualizer Scope

Synthesis Engine 23

For example, when the mouse is used to adjust a control in the Oscillator section, the final waveshape is displayed in the Visualizer.

Using the Filter section results in displaying the current Mode's filter response curve.

Elsewhere, the various parts of the interface feature different Visualizer displays - modulators such as LFOs and envelopes display their respective shapes, for example.

The Visualizer display is updated in real time as any relevant controls are adjusted and also shows the effect of any modulation routed to relevant parameters.

Activating the EUCLID/CURV1/CURV2/ZONE1/ZONE2 buttons in the Scope area displays the corresponding Euclid/Curve/KeyZone processor editor (see below).

Other functions on the Synth page

This chapter covers only functions directly related to the audio synthesis engine. The Synth page also contains a number of editing functions for modulators in Strobe2, which are described in the Modulation chapter:

Dual LFO Strobe2's full-featured LFO includes a secondary 'sub LFO' which is derived by multiplying/dividing the

main LFO rate. The main LFO features direct modulation routings to the Filter Cutoff as well as oscillator Pitch and PWM. The main and sub LFOs can be routed to almost any other parameters in Strobe2 via the TransMod system.

Ramp generator This modulator provides a variety of uses via the TransMod modulation system and can be optionally

looped to provide a polyphonic saw-wave LFO. Mod Envelope This envelope features direct routings to the Filter Cutoff as well as oscillator Pitch and PWM. It can

also be routed to almost any other parameters in Strobe2 via the TransMod system. Amp Envelope This envelope is always directly routed to Strobe2's Amp parameter with 100% depth. It can also be

routed to almost any other parameters in Strobe2 via the TransMod system.

The Scope area provides 3 additional modulator editors: Euclid processor This processor is a combination of an X-Y pad with additional modulation processing with inertia and

slew. Curve processors These editors provide the ability to remap, quantize and slew the shape of a modulation source. KeyZone processors These editors allow custom keytracking responses to be defined.

Strobe224

Pitch, Fine

These controls set the Master Pitch for both the Main Oscillator and the Sub Oscillator.

The Pitch control adjusts tuning in semitones while the Fine control offers an additional offset of +/- 1 semitone (except when the Cents button is deactivated - see below).

The Pitch control can be set in semitones or in just harmonics with optional snapping to whole semitones/ harmonics depending on the current Unit/Snapping mode.

3.1 Oscillator section

Master Oscillator controls

Modulating the Fine control by small amounts with random TransMod modulation sources is useful for creating effects reminiscent of oscillators with unstable tuning.

Please do not confuse the concept of Master Pitch in Strobe2 with the Tune (Master Tuning) control in the Global synth controls section. The Tune control sets the overall tuning by specifying the frequency the A note above middle C between 420 and 460 Hz (the default is 440 Hz). The Pitch and Fine controls used to adjust the Master Pitch are set in semitones and applied relative to the Tune control setting.

Direct modulation

Osc Pitch can be modulated directly using the following dedicated modulation depth controls:

Keytracking LFO Mod Envelope

These controls are affected by the current Unit/Snapping mode.

Reset (Phase Reset)

When the Reset button is enabled, the phase of the oscillator is reset to zero when a new voice is played. This is useful when each note onset is required to be consistent rather than with free-running phase - the latter can lead to audible variation which can be undesirable for some types of bass sounds.

Main Oscillator controls

Main Oscillator Power

Click the Main Oscillator's Power button to activate/deactivate it.

Saw Sqr (Square)

These controls represent the levels of the oscillator's Saw and Square (with variable pulse width) waveforms.

PWM

The Square waveform features variable pulse width which is adjusted using the PWM control.

Direct modulation

The main osc's pulse width can be modulated directly with the following modulation depth controls:

Keytracking LFO Mod Envelope

Synthesis Engine 25

These controls provide an oscillator-stacking function which creates classic multi-osc and detuned unisonstyle sounds using Strobe2's single oscillator - without needing to use additional unison voices.

The Stack control sets the number of stacked oscillators which are added above and below the Master Pitch setting as follows:

2nd: Higher 3rd: Lower 4th: Higher 5th: Lower

Note that these functions only modulate the Pulse Width of the main oscillator's Square wave - the sub osc's Square wave features its own PWM control which must be modulated by the TransMod modulation system.

Sync

The Strobe2 oscillator features a 'hard sync' function: increasing the Sync control increases the frequency of the main oscillator while always re-synchronizing it on each cycle of the Master Pitch set by the Pitch/Fine controls. The sub oscillator is also affected by this function (unless the sub osc's Link button is deactivated).

The resulting waveform has the same overall pitch as the Master Pitch setting but with added complex harmonics that can create a wide range of timbres and effects, especially when the Sync control and other oscillator parameters are modulated.

The Sync control can be set in semitones or just harmonics with optional snapping to whole semitones/ harmonics depending on the current Unit/Snapping mode.

Stack Detune

The Detune control spreads these stacked oscillators away from the Master Pitch, creating a detuning effect. The amount of detuning depends on the state of the Cents button:

• With Cents activated, stacked oscillators are spread up to 1 octave away from the Master Pitch For a 'detuned supersaw' sound, increase the Stack control to 2 or 3 (or any number up to 5!) and then

set the Detune control to taste. To create chord-style tunings, try setting the Detune control to 3, 5 or 7 semitones with the Stack

control at 2 or 3.

• With Cents deactivated, stacked oscillators are spread up to 16 Hz away from the Master Pitch This mode results in a smaller effective detune spread than with Cents activated. However, detuning

occurs with a constant rate of beating across the keyboard range (see below).

Cents (Detune mode)

The Cents button dictates if any Oscillator detuning functions are applied in terms of absolute pitch (cents of a semi-tone) or in terms of frequency (hertz). The state of this button has an effect on the 'beating' that occurs between detuned oscillators when using Unison voices and detuning the Fine control or when using the Stack and Detune controls.

When the Cents button is activated, an absolute pitch deviation in semitones and cents (1% of a semitone) is added to each note on the keyboard before keyboard tracking is applied to the oscillator pitch. This leads to a changing 'beating' rate across the keyboard (the higher the note, the faster the beat rate).

When the button is deactivated, the Fine pitch control provides a range of +/- 100 Hz, while the Detune control provides up to 16Hz of detuning away from the Master Pitch. The specified frequency is added for each note after keyboard tracking is applied to the oscillator pitch. This means that using detuning techniques such as those described above leads to uniform 'beating' rates across the entire keyboard range.

Strobe226

Note that even with the Sub Oscillator deactivated, the Main Oscillator's Sync function is still active as normal.

Sub Osc Link

With the Sub Osc Link button activated, the Sub Osc is affected by the Main Osc's Sync, Stack and Detune functions. With the button deactivated, the Sub Osc tuning is not affected by these functions. Deactivating this button is useful for heavily-detuned sounds anchored by a tuned sub.

Octave

Each of the sub-osc waveforms can be set to the same pitch as the main osc or 1, 2 or 3 octaves below it using the Octave buttons.

PWM

This control adjusts the Pulse Width of the sub-oscillator's Square waveform.

Tone

The Tone filters within the main Osc, Sub-Osc and Noise sections adjust the spectral emphasis of each of these sections before they are mixed and fed into the Filter. These filters are shelf-style EQ filters for emphasizing or de-emphasizing higher harmonics in the signal before the more radical sculpting offered by the Filter section. Changing the spectral balance in this way can alter the way the filter resonance behaves across the frequency range, giving Cutoff sweeps a different character.

Tone filters always track the keyboard so their effect is always consistent throughout the keyboard range, with the centre of the shelf's slope positioned 2 octaves higher than the osc's Pitch setting. Each

Tone control itself sets the amount of gain (increase or decrease) for the keytracking shelf EQ.

Sub-oscillator controls

Sub-osc Power

Click the Sub Oscillator's Power button to activate/deactivate it.

Sine (Sin) Triangle (Tri) Saw Square (Sqr)

These controls represent the levels of the Sub Oscillator's Sine, Triangle, Saw and Square waveforms.

The Square waveform is actually a Pulse waveform with adjustable Pulse Width.

Shape

The Shape control adjusts a waveshaper function on the combined mix of the Sub Oscillator's waveforms, resulting in varied timbres due to the added complex harmonics.

Tone

The Sub Oscillator's Tone control behaves identically to the Tone control for the Main Oscillator (see above).

Noise Generator controls

Noise Generator Power

Click the Noise Generator's Power button to activate/deactivate it.

Noise

The Noise control adjusts the level of Strobe2's Gaussian white noise generator.

Tone

The noise generator's Tone control behaves identically to the Tone control for the Main Oscillator (see above).

Synthesis Engine 27

Strobe228

Filter Power

Click the Filter's Power button to activate/deactivate it.

When the filter is deactivated, the audio from the Oscillator section passes through the filter unaffected.

Cutoff Res (Resonance)

The Cutoff control determines the cutoff frequency of Strobe2's filter.

3.2 Filter (V.C.F.) section

Strobe2's filter is its main source of tonal variation, especially when modulated. While there are direct modulation routings to the filter frequency cutoff from keyboard pitch, LFO and Mod Envelope, the filter's controls can be modulated with the TransMod system for creative and varied effects which go beyond these basic modulation routings.

The filter model is based on an OTA (operational transconductance amplifier) cascaded core, with a diode-based clipper circuit in the feedback section. The modelled diodes in the circuit are slightly mismatched, leading to the characteristic growl of a real analogue filter.

The Res control adds emphasis around the cutoff frequency. At extreme Res settings, the filter circuit exhibits self-oscillating behaviour.

The Cutoff control is adjusted in pitch-based units, allowing it to be tuned just like an oscillator - this can be especially useful when the filter is self-oscillating and effectively behaving as a sine oscillator. It can be set in semitones or just harmonics with optional snapping to whole semitones/harmonics depending on the current Unit/Snapping mode.

Direct modulation

The Cutoff parameter can be modulated directly using the following dedicated modulation depth controls:

Keytracking LFO Mod Envelope

Setting the Keytracking depth control to maximum allows the filter to be played musically from the keyboard.

These controls are affected by the current Unit/Snapping mode.

Drive

The Drive control increases the gain of the signal going into the filter. This overloads the filter's components, drastically changing its sound and character.

This Drive control is gain-compensated - as it is increased, the output level of the filter is reduced so that, while the timbre changes, the level stays constant, meaning that it is unneccessary to compensate increases in Drive by reducing the V.C.A. Amp parameter (and vice versa).

Note that the effective resonance of the filter circuit is reduced as the Drive amount is increased.

Leak

The Leak control allows an adjustable amount of the original signal through, mixed with the filtered output, simulating the effect of a bleeding filter circuit. It allows further timbral options even with the more complex filter Mode settings.

Mode

A large variety of filter modes are available by adjusting the Mode control. Note that filters denoted as 'T' feature 2 or more filters with an octave between the frequency of each.

The first filter in the name is at the cutoff frequency, with subsequent filters each an octave higher than the last. The only exceptions are the last 2 filter modes - see the table below.

Synthesis Engine 29

L2, L4

2-pole (12 dB/oct.) & 4-pole (24 dB/oct.) Low-pass filters

B2, B4

2-pole & 4-pole Band-pass filters

H2, H4

2-pole & 4-pole High-pass filters

2-pole Peak filter

NP2

1-pole Notch and 2-pole Peak filters

N2P2 T

2-pole Notch and 2-pole Peak filters, an octave apart

N2L2 T

2-pole Notch and 2-pole Low-pass filters, an octave apart

N2H1L1 T

2-pole Notch, 1-pole High-pass and 1-pole Low-pass filters, each an octave apart

P2N2 T

2-pole Peak and 2-pole Notch filters, an octave apart

H2N2 T

2-pole High-pass and 2-pole Notch filters, an octave apart

H1L1N2 T

1-pole High-pass, 1-pole Low-pass and 2-pole Notch filters, each an octave apart

N2P2N2 T

2-pole Notch, 2-pole Peak and 2-pole Notch filters, each an octave apart

N2, N4

2-pole & 4-pole Notch filters

N2L2

2-pole Notch and 2-pole Low-pass filters

H2N2

2-pole High-pass and 2-pole Notch filters

H1N2L1

1-pole High-pass, 2-pole Notch and 1-pole Low-pass, each an octave apart

N2N2A T

2-pole Notch with 2-pole Notch an octave higher than the cutoff frequency

N2N2B T

2-pole Notch with 2-pole Notch an octave lower than the cutoff frequency

In other combination filters, all filters act at the cutoff frequency. See later in this manual for graphical representations of the frequency response curves for each Mode.

Strobe230

Amp

The Amp parameter is always directly modulated by the Amp Envelope - its value represents the amplitude at the maximum value of the AmpEnv (at the end of its attack stage).

The Amp section features a modelled VCA circuit which can be overloaded like that of a real analogue synth VCA (voltage-controlled amplifier) resulting in non-linear distortion characteristics.

3.3 Amp (V.C.A.) section

The Amp section represents the final output of the synth circuit before it enters the FX processing blocks. It articulates each synth voice in terms of its output level and its position within the stereo field.

For a cleaner sound, keep the Amp control at low settings and increase the Level. When overloading the V.C.A. by increasing the Amp parameter, remember to turn down the Level

control. Otherwise the output of Strobe2 may clip. In order to achieve a velocity-sensitivity response for amplitude (so that harder velocities result in a

louder sound), modulate the Amp parameter with velocity (the OnVel+ source) using the TransMod system - this is already set up in TransMod slot 1 in the Strobe2 Init preset.

Pan

The Pan parameter sets the position of the voice in the stereo field. Try modulating this control with the TransMod system using a Voice or Unison modulation source – this

leads to a rich stereo spread of chords or multiple unison voices.

Level

This parameter sets the final Level of each voice before it is summed with all other active voices. If this parameter's value is set too high, the output of Strobe2 entering the Effects section may clip.

Suitable settings for this parameter depend upon context - care should be taken especially with polyphonic sounds to allow enough headroom for the output not to clip when multiple voices are mixed.

Please note that this parameter is monophonic and sets the level for all active voices - to achieve amplitude modulation per-voice, modulate the Amp control rather than the Level.

Analogue

The Analogue parameter simulates the effect of noise and mains hum in certain parts of the audio and control signal paths, something that always occurs in real analogue synth circuits. At lower settings, it leads to a subtly gritty and slurring character, while higher settings create a more unstable and noisy sound.

+ 71 hidden pages

FXpansion STROBE-2 Operation Guide

Specifications and Main Features

Frequently Asked Questions

User Manual

1 Strobe2 Introduction

Interface overview

1.2 Adjusting sliders and rotary controls

1.3 Adjusting TransMod modulation

1.4 Other controls and indicators

1.5 Unit and Snapping modes

1.6 Locks

1.7 Parameter context menu

2 Browsing presets

3 Synthesis Engine

3.1 Oscillator section

3.2 Filter (V.C.F.) section

3.3 Amp (V.C.A.) section