Contents

Glossary of terms

Interface summary

Trails is a four-channel gesture recorder and transformation instrument. Record movements on the touchpad, then reshape, quantise, synchronise and reinterpret them to generate evolving CV, gate and MIDI sequences.

Touch surfaces

The Touch Pad is a mutual-capacitive sensor and the Touch Bar a self-capacitive sensor, both with LEDs mounted behind them. The STATE switch selects one of four working modes (INPUT, ADAPT, METER, FADER) which determine the behaviour of the Touch Pad and Touch Bar.

In INPUT, METER, FADER: open the Bar Function menu by holding SHIFT and touching the Touch Bar with two fingers.

Buttons

The functions of the buttons are listed in the table below. Some buttons can be used as modifiers in combination with the channel buttons to toggle the setting specified in the Hold + channel button column. Hold the global button down to visualise the setting's current state on each channel's LED: a green LED means the toggle is currently on; a red LED means the toggle is currently off. Pressing the channel button while the global button is held toggles the state.

Inputs and outputs

The outputs are carried on a separate board, supplied assembled on a 3U 4HP panel that sits alongside the module. An optional 1U 22HP panel in Intellijel format comes with the module, should you prefer to mount the outputs in a row above the module; the output board transfers onto it (see Assembly, below). Both connect to the main PCB with the same 24-pin ribbon cable.

Core concepts

Trails is built around four independent channels of gesture recording and playback.

Each channel can record, transform and replay its own gesture while remaining synchronised to the others. Channels can operate independently or be combined to create layered melodic, rhythmic and modulation structures.

4 independent channels

Each channel features:

• A gesture buffer
• X, Y and Gate outputs
• Independent playback and transformation settings

Channels can be edited individually or in groups. Multiple channels may be active at the same time, allowing a single action to affect several channels simultaneously.

Channel states

The channel buttons indicate the current state of each channel.

Active (White)

The channel is available for editing and is visualised on the display.

Inactive (Blue)

The channel continues to play and produce outputs, but it is not visualised and cannot be modified.

Muted (Unlit)

The channel outputs are muted, but the gesture and all channel settings are retained.

Recording reset (Flash unlit)

When a channel is active, it briefly flashes unlit when the gesture resets.

Paused (Yellow)

The channel is active and in the paused state. Note that the visualisation of inactive channels is not affected by their paused state.

Channel button shortcuts

NOTE: the SCALE shortcut restores the channel's last axis configuration from the QUANTISATION menu if one exists; otherwise it enables pitch quantisation for both X and Y. To access per-channel control, use the corresponding menu page.

Hold your finger down on the modifier button to preview the toggle states on the channel LEDs.

4 states

The STATE switch selects one of four working modes.

INPUT

Create and record new gestures. INPUT is where gestures are drawn and recorded into channel buffers.

ADAPT

Transform existing gestures. ADAPT provides non-destructive spatial transformations such as offset, scaling, rotation and waveshaping.

METER

Manipulate time. METER provides a timeline view for controlling playback position, loop boundaries, pattern rotation, speed and other temporal relationships.

FADER

Direct control and automation. FADER presents the channel outputs as a bank of faders and provides access to automation and preset-based control.

A useful way to think about the four states is:

The settings menu

Enter the menu by holding down SHIFT and tapping the touchpad with 2 fingers.

The main page of the menu contains eight selectors; hold your finger on a selector to see the setting name as scrolling text. The settings are:

• Voltage Ranges — select a channel to set the voltage ranges for each axis. See Voltage ranges.
• Quantisation — toggle pitch and time quantisation and looping per channel. See Quantisation.
• Clocks — see Clock & reset routing.
• Tuning of output CV — see Calibration of outputs.
• Visualisation — set the persistence amount, i.e. trail length, and the brightness. See Visualisation.
• Version info — find out which firmware version you are running. See Troubleshooting.
• The remaining selectors are reserved for future use.

Resetting individual settings

Settings can be returned to their defaults one group at a time, without resetting the whole module.

To reset a group of settings in the menu, hold UNDO and tap that setting's selector. For example, to restore the default output ranges, open the settings menu, hold UNDO and tap the Voltage Ranges selector. The selector flashes on and off to confirm that the setting has been reset.

The same shortcut works for the STEP and SCALE pages. Hold UNDO and tap STEP or SCALE to return those settings to their defaults; the button flashes yellow to confirm.

Note that resetting a setting this way always applies to all four channels, regardless of which channels are currently active.

Reboot module with default settings

Are you lost and want to return to the default settings? Hold down UNDO; after 7 seconds you will see RESET? on the touchpad and the bar will start to fill up. Once the bar is full the module will reset with factory settings. Note that this will not affect the factory calibration of outputs but will override any manual tuning performed via the settings menu.

State 1: INPUT

INPUT is the primary performance and recording mode of Trails.

In this state, gestures performed on the touchpad are recorded as pathways and converted into CV and gate signals. Each of the four channels can store its own independent gesture, allowing Trails to generate multiple streams of control voltage from a single performance.

As you draw on the touchpad, the X and Y outputs continuously generate CV corresponding to the position of your finger. The gesture is recorded, allowing it to be replayed and transformed.

INPUT mode is all about creating source material. Gestures recorded here form the foundation for the transformations, rhythmic processes and compositional techniques available elsewhere in the instrument.

Recording

Every touch on the pad is automatically recorded and produces live CV and gates. By default, the gesture begins playing back the moment you lift your finger.

Without a clock, recording duration is simply how long your finger stays down. With a clock, recording begins on a clock edge and lasts for one or more cycles, so loops always stay in sync (see Automatic number of repeats, below). You can control the duration of a recording manually by pressing REC, which allows recording gestures that include silence (see Recording multiple touches, below).

Once a gesture has been recorded and is playing back, hold REC to overdub on top of what's already there, or hold REC and tap UNDO to punch in a stretch of silence (see Overdubbing, below). Hold SHIFT to lock the touchpad and perform on top of a recording to avoid changing it inadvertently.

Recording multiple touches

By default, a recording consists of a single continuous touch. Recording begins when the touchpad is touched and ends when the finger is lifted.

The REC button allows you to record multiple touch events into a single loop, including pauses between gestures.

1. Tap REC once to arm recording. The button will illuminate yellow. Recording begins when there is a new touch, or on a second press of REC, which will start the recording with silence.
2. When recording begins, the button turns red. You can now lift your finger from the touchpad multiple times during the recording, so that your recording can contain multiple sections of silence.
3. Tap REC again to stop recording. Recording will continue until the next cycle before playback begins. If you have explicitly set a number of Repeats then the recording will last for that duration and stop automatically.

This makes it easy to create sequences of gestures that remain synchronised to the rhythmic grid.

Overdubbing

Hold REC and touch the Touch Pad to overdub an existing recording. Any new touch gestures performed on the touchpad replace the current section of the recording while playback continues.

Only touch events are recorded during an overdub. Holding REC without touching the pad does not overwrite the recording with silence and does not erase existing material. Press UNDO while holding REC to erase existing material and replace it with silence. This allows additional gestures to be layered onto a recording without affecting sections that are left untouched.

Abort recording

Whilst recording, tap UNDO to abort the current recording. Note that any pre-existing recording is lost.

Touchpad lock

The touchpad can be locked to prevent accidental changes to the current recording.

Hold SHIFT for 1 second to lock the touchpad on release of the button.

While locked you can continue to perform on the touchpad and generate CV and gate outputs, but the underlying recording will not be modified. Tapping SHIFT unlocks the touchpad again.

This is useful when rehearsing ideas, auditioning changes or performing live while preserving an existing gesture, or just to prevent recording.

Pause

Every active channel can be paused and resumed. Pausing freezes a channel's outputs without modifying its recording.

Tap PLAY to pause or resume the active channels. If any active channel is playing, PLAY pauses all of them; if all active channels are already paused, PLAY resumes all of them. To pause or resume a single channel, solo it first, then tap PLAY. Pausing freezes the playhead and holds the X, Y and GATE outputs at their last value; gates stay silent. The clock itself is never paused, only playback, so a recording elsewhere still quantises to cycle boundaries as normal.

Interacting with a paused channel

You can still touch a paused channel in INPUT and FADER mode and move the point around, holding the last value you touch on lift-off.

Try applying Smooth to a channel and interacting with the paused point — you now have individually controllable slew for each channel.

NOTE: a paused gesture cannot be transformed, and the ADAPT page will display an amber frame if you try to interact with it. Resume playback to apply a transformation.

Reset

Resetting a channel resets its playhead to the start. On a channel whose looping is off, a reset signal will reset it and restart playback immediately. On a channel that is paused, reset also resumes playback.

There are two ways to reset a channel:

• Hold SHIFT and tap PLAY to reset all active channels.
• Send a trigger into the reset input, as set in the Clocks menu. By default, inputs 1 to 4 work as reset inputs for the respective channels. See Clock & reset routing, below.

Looping

When looping is on, a channel's gesture loops indefinitely. When looping is off, once the playback reaches the end the channel's output is muted until it receives a reset signal, at which point the gesture starts playing back from the beginning. Non-looping channels behave like a one-shot envelope generator. Looping is enabled by default and can be toggled per channel via the menu, or by holding PLAY and pressing a channel's button.

Quantisation

Trails provides two independent forms of quantisation:

When quantisation is disabled the X and Y outputs generate continuous control voltages corresponding to the recorded gesture. The GATE output produces a trigger whenever the gesture returns to the start of its loop, or after each silent section in the recording. This allows Trails to function as a free-running gesture recorder, capable of generating smooth modulation, envelopes and continuously evolving control signals.

Quantisation is disabled by default on all channels.

Quantisation settings

To access the Quantisation menu, hold SHIFT and tap the touchpad with two fingers to enter the settings menu, then press the quantisation selector (second from the left on the top row).

Quantisation settings are presented for each channel in the following order:

Pitch 1.X, Pitch 1.Y, Loop 1, Time 1
Pitch 2.X, Pitch 2.Y, Loop 2, Time 2
Pitch 3.X, Pitch 3.Y, Loop 3, Time 3
Pitch 4.X, Pitch 4.Y, Loop 4, Time 4

Pitch

Pitch quantisation can be enabled independently for each channel and axis. This allows a single gesture to control both quantised and continuous parameters simultaneously. For example, the X axis can control pitch while the Y axis controls filter cutoff. When pitch quantisation is active, the available voltage range is divided into discrete voltage levels corresponding to notes in the selected scale.

Time

Time quantisation applies a sample and hold to the gesture, splitting it into a sequence of steps with fixed voltages. A trigger pulse (with variable pulse width) for each step is generated at the corresponding gate output. If a clock is present, the step duration is set by the clock frequency and the specified length or step ratio settings from the STEP page. By default, the gesture will be split into 8 steps.

SCALE page

The SCALE page allows you to define the pitch space used by pitch quantisation.

When pitch quantisation is enabled via the menu, recorded voltages are constrained to the notes selected on the SCALE page.

Custom scales

Press SCALE to open the scale editor.

The scale editor displays a two-octave keyboard. Each octave sets the quantisation for a 1 V output range. The bottom octave sets the quantisation for octaves starting at even Volt values (e.g. 0 V, 2 V, etc.) while the top octave sets the quantisation for octaves starting at odd Volt values (e.g. 1 V, 3 V, etc.).

Scales are stored per channel, and the colour of enabled notes represents the channel that they pertain to. Tap notes to enable or disable them. Enabled notes become available to the quantiser, while disabled notes are ignored. Only active channels are affected by note changes. Changes made while multiple channels are active are applied to all active channels simultaneously.

Transposition

Press SCALE again to enter Transpose mode.

The keyboard background changes colour to blue, the whole keyboard shifts to the left and a top C is added. The keyboard is now selecting a root note rather than editing the scale itself. Only one note can be selected at a time.

The default note is the leftmost C of the top octave. Selecting a note applies a transposition after the quantiser, transposing the whole sequence up or down by the interval relative to the default note. For instance, pressing E on the top octave transposes up by a major third (four semitones up) and pressing A on the bottom octave transposes down by a minor third (three semitones down).

Press SHIFT to exit.

Preset tunings

Hold SHIFT and press SCALE to open the Preset Tunings page.

Keyboard uses the scale defined on the keyboard in Custom scales. Other options allow you to select from a list of preset scales.

If you change a note on the keyboard while a preset scale is selected, this will automatically switch to using the custom scale drawn on the keyboard.

Editing multiple channels at once

Any setting changed on the SCALE or STEP pages while multiple channels are active applies to all of them. Where the active channels currently hold different values for a setting — for example all channels are active but there are different preset scales selected on channel 1 versus channels 2–4 — then the value is shown as ≠ rather than a number. Changing it from that state sets all active channels to the new value, replacing whatever they held individually. To see or set a value for one channel alone, simply solo it.

STEP page

The STEP button opens a two-page menu covering the rhythmic structure of each channel.

Page 1: Length & Repeats

Tap STEP once to open the first page. Two parameters are shown:

• Length: the number of incoming clock pulses that make up one cycle (default: 8). Cycles form the rhythmic grid used for quantisation, recording and looping. STEP means that the step ratio has been changed.
• Repeats: the number of cycles contained in a recording. AUTO lets Trails determine loop length automatically, based on how long recording remains active (see Automatic number of repeats).

Scroll a finger up or down on the touchpad to change the highlighted value. When a value has been changed it will flash. Tap STEP to apply the change and hear its effects while staying on the page, or tap SHIFT to apply and exit.

By default, each clock pulse advances the recording by one step, so Length alone is enough to set up straightforward rhythms synced to the incoming clock.

Page 2: Step Ratio

For more complex rhythmic structures, tap STEP again to move to the second page. Here you can decouple the number of output steps from the number of incoming clock pulses.

Two numbers are shown: the top is output steps per cycle, the bottom is input clock ticks per cycle. When changing Length on the previous page, that sets these numbers to the same value as Length.

Examples

Polymeter

Each channel can have its own independent Length, set on STEP page 1. For example:

• Channel 1: Length 4
• Channel 2: Length 6

In this configuration, both channels advance one step per clock pulse (the default 1:1 ratio), but Channel 1 completes its cycle after four clocks while Channel 2 completes its cycle after six. The two cycles move in and out of phase before realigning every twelve clocks.

Similarly:

• Channel 1: Length 5
• Channel 2: Length 7

creates two independent cycle lengths that continuously shift against one another, producing evolving patterns while remaining synchronised to the same master clock.

Polyrhythm

Unequal step counts can be used to create polyrhythms by distributing a different number of events across the same cycle length. This requires STEP page 2, where the number of output steps can be set independently of the input clock ticks. For example:

• Channel 1: 3:4
• Channel 2: 4:4

Both channels share a four-clock cycle, but Channel 1 generates three evenly spaced events while Channel 2 generates four. The result is a classic 3-against-4 polyrhythm. Likewise:

• Channel 1: 5:4
• Channel 2: 4:4

creates five evenly spaced events across the same duration as four, producing a 5-against-4 relationship.

Because Length and step ratio are set independently on all four channels, Trails can create anything from simple clock divisions to complex layers of polymeter and polyrhythm from a single gesture.

Musical applications

Polymeter turns two simple, unrelated Length settings into a relationship that keeps evolving: Channel 1 at Length 5 and Channel 2 at Length 7 realign only once every 35 clocks, so a patch can run for minutes without repeating exactly. Use it to create generative or ambient material you want to set running and leave alone.

Polyrhythm is more about the moment-to-moment feel: setting Channel 1 to 3:4 against Channel 2's 4:4 recreates the cross-rhythms found throughout minimalist and West African-derived music, where two simple, regular pulses interlock into something neither channel plays alone. Try recording on two or more channels simultaneously and only changing the ratio to hear the effect in isolation.

Automatic number of repeats

With Repeats set to AUTO, Trails can automatically determine the length of a recording based on how many cycles are captured while a gesture is being performed.

A cycle is the repeating rhythmic unit defined by the STEP settings. Recording lengths are quantised to complete cycles regardless of when a recording starts.

For example, if the cycle length is set to 4 clock ticks:

• Recording only during beats 1 and 2 will create a loop that is one cycle long. The resulting recording contains silence on beats 3 and 4, with your gesture on beats 1 and 2.
• Recording across beats 1, 2, 3, 4 and continuing into beat 1 of the next cycle will create a loop that is two cycles long. The first cycle contains the full gesture, while the second cycle contains only the material recorded on beat 1.

When using AUTO repeats it is possible to tap the REC button again to end the recording at the next cycle boundary; playback begins immediately, even if your finger remains on the touchpad. This is useful for improvising but then being able to end a recording without having to get your timing perfect.

Fixed repeats

The Repeats parameter allows you to specify exactly how many cycles should be recorded.

When set to a number, recording automatically stops after the specified number of cycles and playback begins immediately, even if your finger remains on the touchpad. For example:

• Repeats = 1 records exactly one cycle.
• Repeats = 2 records exactly two cycles.
• Repeats = 4 records exactly four cycles.

Recording length is always measured as multiples of the cycle boundaries established by the STEP settings. For example, if the cycle length is 4 clocks and Repeats = 2, recording will always last 2 cycles, regardless of when recording begins. Each channel can have its own independent Repeats setting.

Internal clock

Trails includes an internal clock generator which can be used instead of or in addition to an external clock source.

Hold SHIFT and tap STEP to open the Clock page.

The BPM can be adjusted at the top of the screen. The white selector allows you to toggle the internal clock on or off.

The coloured buttons at the bottom of the touchpad are for assigning the clock from a currently playing channel to the internal clock. Say you started improvising without a clock and you like the sound of a pattern you landed on: use these buttons to capture the BPM of that channel and apply it to the internal clock, so that it can be used as a time reference for new recordings.

Clock & reset routing

Clock and reset routing can be set per channel in the dedicated menu entry. Hold SHIFT and tap the touchpad with two fingers to open the menu, then select "input" (second from the right on the top row).

For each of the four channels, the input page allows you to set a Clock Source, a Clock Type and a Reset Source.

Together, these three settings determine where a track's clock comes from, how the track responds to that clock, and what resets it back to the start of its gesture.

Clock Source

Clock source selects the clock source for the track.

• AUTO (default) follows whichever clock is available in order of priority: the CLK input, or the internal BPM clock if enabled (see Internal clock, above).

Alternatively, a track can be pinned to one specific source:

• BPM: the internal clock, regardless of whether it is enabled or not.
• NONE: no clock; the channel's gesture plays back with the speed at which it was recorded.
• CLK: the CLK input.
• IN1, IN2, IN3, IN4: any of the four channel control inputs, used as a clock source.

CLK, IN1, IN2, IN3 and IN4 are the module's physical inputs; BPM, AUTO and NONE are internal sources.

Clock Type

Clock type sets how the track behaves in response to its clock.

FOLLOWER (default)

The default playback behaviour: the track follows the clock and adapts its playback rate to the interval between ticks.

STEPPED

Every clock tick advances the gesture by one step.

• With temporal quantisation enabled, this is the behaviour expected of a sequencer follower: each tick advances one step, and the output is sampled and held until the next tick.
• With temporal quantisation disabled, the gesture is instead divided into the set number of output steps, and each incoming trigger plays back one slice of it. When a slice finishes playing, its last value is held until the next trigger arrives. If a new trigger arrives before the current slice has finished, the gesture jumps straight to the next slice.

Unlike FOLLOWER, STEPPED never tries to infer a playback rate from the interval between triggers, so it stays usable with sparse or irregular trigger sources. It also never crosses a step boundary without a clock tick, which has one consequence worth remembering when changing the playback speed from METER: with temporal quantisation enabled, the speed control has no effect; with temporal quantisation disabled, it changes the speed at which each slice is played back (see State 3: METER / Speed control).

Reset Source

Selects the source that resets a channel back to the start of its gesture, independently of its clock. Defaults to the IN channel corresponding to the channel's number. Options: NONE, MIDI, CLK, IN1, IN2, IN3, IN4.

Example configurations

The Touch Bar

In INPUT mode, the Touch Bar's behaviour is chosen from the Bar Function menu.

Bar Function menu

Hold SHIFT and touch the Touch Bar with two fingers to open the Bar Function menu. The pad shows scrolling text reading "bar function", and the Touch Bar itself divides into five zones, one per function:

• Smooth
• Volume
• Portamento
• Gate
• Density

These work as radio buttons: only one can be selected at a time. Hold a finger on a zone to see its name scroll across the pad before committing; tap to select it, and the Touch Bar immediately adopts that function.

The selection is global — it applies to the Touch Bar as a whole, rather than per channel — and is saved, so it is restored after a power cycle. Touching the bar affects the active channels only, so it is possible to have different values and recordings of movement on each channel.

Density

When Density is selected in the Bar Function menu, the Touch Bar controls the density of GATE events (this currently only affects channels that have temporal quantisation enabled).

Moving the Touch Bar towards the left progressively mutes steps within the pattern. Trails distributes the remaining events using a Euclidean algorithm, creating rhythms with the greatest possible degree of evenness.

This produces musically useful patterns ranging from steady pulses to sparse rhythmic structures.

By default, the Touch Bar is fully open and all steps are active. Sliding towards the left gradually reduces the number of active steps.

The resulting rhythm depends on the number of steps in the pattern. For example, an 8-step pattern and a 16-step pattern will produce different Euclidean rhythms for the same density value.

Worked example: holding the Touch Bar at the same position (around 60% density) while changing Length from 8 to 9 to 12 to 15 shows how much the resulting pattern can change (X = active step, · = muted step):

Length 8  (5 of 8 active):  X · X X · X X ·
Length 9  (5 of 9 active):  X · X · X · X · X
Length 12 (7 of 12 active): X · X · X X · X · X X ·
Length 15 (9 of 15 active): X · X · X X · X · X X · X · X

Four different Lengths, four distinct groupings, none of them just a straight subdivision. That's the point of trying a few lengths side by side: the same Touch Bar position can sound very different depending on the Length.

The rotation of the Euclidean pattern can be adjusted on the METER page.

The density control is latched and remembers the last value you set it to, even when you draw in new gestures.

Musical applications

The Touch Bar transforms Trails from a gesture recorder into a pattern generator.

By combining gesture recording, temporal quantisation and Euclidean density control, it is possible to create evolving melodies, shifting rhythmic patterns, generative sequences and continuously varying polyrhythms from a single performance.

Recording performances on the Touch Bar

Auto-record

Movements performed on the Touch Bar can be recorded alongside touchpad gestures.

While recording a gesture, move the Touch Bar to capture changes in rhythmic density over time. These changes become part of the recording and are replayed along with the gesture.

Trails records the position of the Touch Bar rather than the resulting setting change. In the case of Euclidean density, this can have interesting musical results, as changing the STEP settings after recording can produce entirely new rhythms from the same recorded Touch Bar movement.

For example, a Touch Bar recording created with an 8-step pattern will generate different rhythmic results if the number of steps is later changed to 16. This allows a single performance to be reinterpreted in different rhythmic contexts.

Overdubbing

If a recording already contains Touch Bar movements, they can be overdubbed independently from the gesture on the Touch Pad. Hold REC and move the Touch Bar to record new density changes without re-recording the gesture itself.

Moving the Touch Bar without holding REC does not alter the recording. This allows you to experiment, rehearse and perform with different density settings without committing them to the loop.

This distinction makes it possible to treat the Touch Bar either as a live performance control or as a recordable modulation source.

Deleting a recording

If you have a recording on the Touch Bar and wish to go back to using the Touch Bar as latched, hold UNDO and tap the Touch Bar to discard the recording.

Gate pulse width

When Gate is selected in the Bar Function menu, the Touch Bar controls GATE pulse width, from 0% to 100%. This only applies to channels with time quantisation enabled.

Smooth

When Smooth is selected in the Bar Function menu, moving the Touch Bar applies a smoothing filter to the recorded X and Y positions.

As the Touch Bar moves towards the left, movement becomes increasingly damped. Rapid changes are reduced and gestures become smoother, eventually appearing to "freeze" around a particular position.

Unlike volume control, smoothing does not reduce the voltage range of a gesture. Instead, it reduces the speed at which values can change, causing the output to lag behind rapid movements.

This can be useful for:

• Creating slower, more fluid gestures
• Holding a position while preserving subtle movement
• Gradually freezing a complex recording
• Smoothing abrupt transitions between gestures

The smoothing filter affects X and Y outputs only and does not affect GATE outputs.

Volume

When Volume is selected in the Bar Function menu, the Touch Bar attenuates the overall level of the channel's X and Y CV outputs, acting as a master level control. Moving the Touch Bar right increases output level; moving it fully left attenuates the channel towards silence.

Portamento

When Portamento is selected in the Bar Function menu, the Touch Bar controls glide time between steps in a time-quantised gesture.

At minimum settings, notes change immediately from one pitch to the next. Increasing the glide time introduces smooth transitions between notes, creating portamento and continuous pitch movement between quantised values.

Glide is applied after quantisation, allowing discrete melodic structures to be combined with fluid pitch transitions.

State 2: ADAPT

ADAPT is used to transform existing recorded gestures.

Where INPUT is concerned with creating gestures, ADAPT is concerned with reshaping them. Transformations are applied non-destructively, allowing a pathway to be stretched, rotated, offset and manipulated without altering the original recording.

Each transformation can be performed live, recorded into the transformation buffer, or removed using the UNDO button.

Touch Pad transformations

Two different transformations are available on the Touch Pad. Use the SHIFT button to toggle the active transformation. The colour of the SHIFT button reflects the currently enabled transformation: dark for scale, red for rotate.

Scale

Two-finger pinch. Scale and offset the pathway in two dimensions. This allows gestures to be expanded, compressed and repositioned within the touchpad space.

Rotate

Rotation gesture. Rotate the pathway around its centre point.

Rotation can dramatically change the resulting relationship between the X and Y outputs, producing new trajectories and interactions from existing material. When only one of the outputs is in use for a given channel, rotation allows you to progressively bring in material from the unused axis.

The Touch Bar

Spatial warping

The Touch Bar applies a waveshaping warping to the pathway.

Rather than simply scaling or offsetting the gesture, this process bends and reshapes the recorded trajectory, introducing new curves, inflections and intersections, adding movement to an existing gesture.

At low amounts the effect subtly alters the shape of a pathway. At higher settings it can generate trajectories that would be difficult or impossible to perform by hand.

The transformation is applied continuously, making the Touch Bar a powerful tool for exploring variations of a recorded gesture.

Recording transformations

Transformations can be performed live, recorded, or held.

Tap REC while performing a transformation to record the movement into the transformation buffer. The duration of the recording will be a multiple of the gesture length.

Tap PLAY while performing a transformation to latch the final value when lifting the fingers from the controlling pad.

Recorded transformations remain non-destructive and can be adjusted, replaced or removed at any time.

Undo and redo

Press UNDO to remove the most recently recorded transformation. Hold SHIFT and press UNDO to restore the previously removed transformation.

State 3: METER

METER is used to manipulate time.

Where INPUT focuses on creating gestures and ADAPT focuses on transforming their shape, METER focuses on how those gestures unfold over time.

In this state, each channel is displayed as a horizontal timeline representing its loop. Playback position, loop boundaries, rhythmic relationships and timing behaviour can all be viewed and adjusted from a single screen.

Each channel occupies one quarter of the display. A moving playhead indicates the current playback position within the loop. When temporal quantisation is enabled, the playhead advances in discrete steps where display resolution allows.

METER provides a macro view of the recording in the instrument, making it possible to understand and manipulate the temporal relationships between multiple channels.

Playback position

Tap anywhere on a timeline to move the playhead to that position. Touch and hold to keep the playhead fixed at a specific location. Drag along the timeline to scrub through the recording.

This can be used to manually explore a gesture, reposition the phase of playback or create performance effects.

For channels that have temporal quantisation enabled, the playhead will jump on the channel's next output clock tick.

The Touch Bar

In METER, the Touch Bar is multi-function, just as in INPUT. Hold SHIFT and touch the Touch Bar with two fingers to open the Bar Function menu and choose between Start/End Points, Speed and Nudge. Touching the bar only affects active channels.

Start/End points (default)

Adjust the start and end points of the channel's loop on the Touch Bar. By default, loop boundaries remain latched after being set.

Adjusting the loop boundaries allows shorter phrases, repeating fragments and shifting rhythmic structures to be extracted from longer recordings.

Speed control

The Touch Bar controls the playback speed of the active channels. The centre position represents the original playback speed. Move left to slow playback; move right to increase playback speed. This makes it possible to create temporary accelerations, slowdowns and phase relationships between channels.

When the Touch Bar is released, playback automatically resynchronises with the incoming clock over a few ticks. The channel eventually synchronises itself to the input clock while preserving its current musical position.

Tap PLAY while adjusting speed to latch the value when releasing the finger.

Nudge

Two selectors appear on the Touch Bar. Tap a selector to move the playhead forwards or backwards by a single step.

Rotation shifts the position of rhythmic events while preserving the underlying pattern. This is particularly useful for creating phasing effects and evolving rhythmic relationships between channels — for example, two identical patterns can be shifted out of phase by one step, producing the shifting patterns found in works such as Clapping Music by Steve Reich.

With Euclidean patterns, Nudge also rotates the pattern within its Euclidean distribution.

State 4: FADER

FADER provides direct access to the X and Y outputs of all four channels.

Where the previous states focus on gestures, transformations and timing relationships, FADER presents the channel outputs as a bank of continuous controls that can be performed directly. Each channel's X and Y outputs are represented as faders, allowing values to be adjusted manually in real time.

Touching a fader temporarily overrides the current output without modifying the underlying recording. When released, playback returns to the recorded value. This makes it possible to perform with existing material while preserving the original gesture.

Overdubbing with faders

Hold REC while moving a fader to overwrite the current value. This allows you to overdub a channel's content on one axis at a time, leaving the other channel untouched.

Faders can therefore be used both as a performance surface and as an alternative method of creating control signals.

Bar functions

The Touch Bar works exactly as in INPUT mode. The selected bar function is always the same between the two.

Fader Bank

In the FADER state, press SHIFT to enter or exit Fader Bank mode. The colour of the SHIFT button reflects the current state: it is red when Fader Bank is enabled.

Fader Bank is an almost entirely independent sub-mode. The relationship to the original gesture is removed and the channel outputs behave as a bank of programmable values and automation. The only settings that apply in this mode are pitch quantisation, scales, CV ranges and tuning.

The Fader Bank consists of:

• 8 faders
• 8 presets

Each preset stores a complete set of fader positions.

Preset morphing

The Touch Bar can be used to navigate between presets: tap a location on the Touch Bar to jump directly to a preset.

This allows complex movements to be created by morphing between stored states rather than manually adjusting individual faders.

Preset slew

The Touch Bar is used to control a global slew time for preset changes.

Hold SHIFT and tap the Touch Bar to adjust the slew time between presets. Longer slew times create gradual transitions, while shorter times produce more immediate changes.

External control

Presets can also be selected using an external signal.

Trigger advance

When the STEP button is illuminated green, triggers received in the IN1 input advance through the preset bank one preset at a time. This makes it possible to sequence preset changes rhythmically.

CV scanning

When the STEP button is unlit, a ramp or continuous control voltage in IN2 can be used to scan through the preset bank.

Rather than stepping between presets, Trails interpolates between neighbouring presets, creating continuously evolving control signals. This allows external sequencers, LFOs and modulation sources to animate the entire fader bank.

Slew

IN3 can be used to externally control slew amount with a CV signal. Please note that this value will be summed with any value set on the bar.

Settings

Calibration of outputs

Your module was calibrated in the factory, but if the V/octave tracking seems a bit off it is possible to manually tune the outputs by ear or with the use of a multimeter.

Open the menu and select "tuning" (first from the right on the top row). First select the output via the on-screen buttons, then adjust the two sliders. The top slider is offset, the bottom slider is scaling. In general, they'll both need adjusting. Give it a bit of time to warm up before tuning: offset in particular can be temperature sensitive. If the measured voltage changes slightly when you let go of the finger, you can press SHIFT while your finger is still down to store the exact value.

For each channel, the procedure is as follows:

1. First, with no gesture playing back, use a multimeter set to the smallest voltage range and adjust the offset slider so the outputs are 0 V.
2. Next, set quantisation to octave and set the output to the highest note by recording a short gesture consisting of a static point in the top right. The nominal voltage you expect at the output is the same as the top of the output CV range for the channel. Measure the output voltage with the multimeter set to the smallest range that fully contains the nominal voltage. The initial reading should be off from the nominal voltage by no more than 100 mV. If you read a voltage that is off by more than 1 V from the expected value, double-check the CV ranges and that the gesture you recorded is as far as possible in the top-right corner. Once the initial reading is within 100 mV of the nominal voltage, adjust the scale slider until you read the nominal voltage and all digits after the decimal point are set to 0 (e.g. 3.00 V or 5.000 V).

Voltage ranges

The Voltage Ranges page sets the output range of each channel's X and Y outputs independently. Outputs can be set anywhere between −5 V and +10 V.

Open the settings menu and select Voltage Ranges. A column of selectors appears down the left of the screen, one for each channel, shown in the channel colours. Tap a selector to choose a channel.

Two horizontal sliders then appear on the lower half of the touchpad. The upper slider sets the range of the X output, and the lower slider sets the range of the Y output. Each slider has two pointers, marking the minimum and maximum voltage of that output. Drag a pointer to move it; only one pointer can be moved at a time. The current values are displayed on screen as numbers as you change them.

Adjustments take effect immediately. If a gesture is looping while you edit, you will hear the range change in real time, making it easy to set a range by ear against the receiving module.

Voltage range settings are stored per channel and retained when the module is powered down.

Visualisation

This menu item allows you to control the brightness and persistence of the LEDs in the module.

Persistence controls how long the LEDs take to decay, determining the length of the trail visible on the display. At low settings only the current touch position is lit, giving a clear view of where a gesture is now. Higher settings leave a longer trail behind the playhead, revealing the shape of the whole pathway as it moves.

Brightness sets the overall intensity of the display. The two controls interact: a long trail at high brightness can leave the display looking crowded, since older parts of the gesture remain almost as bright as the current position, while reducing brightness makes the decay easier to read. It is worth experimenting to find a balance that suits your style of playing and lighting conditions.

Note that increasing brightness can significantly increase the current draw of the module. This is important to bear in mind if your case is running close to its power budget.

MIDI I/O

Trails supports both USB MIDI and TRS MIDI.

USB MIDI I/O

USB MIDI is enabled by default via the USB-C port on the rear of the module.

Each X and Y output is transmitted on its own MIDI channel, allowing gestures to be routed independently to external hardware and software.

Pitch information can be transmitted either as MIDI notes or as high-resolution 14-bit MIDI CC messages.

MIDI mapping

Each X and Y axis is transmitted on its own MIDI channel.

This allows the X and Y outputs of each Trails channel to be used as independent MIDI note streams when pitch and temporal quantisation are enabled. Keeping each axis on a separate MIDI channel ensures that receiving devices can distinguish between the two streams.

When both pitch quantisation and temporal quantisation are enabled, Trails sends MIDI Note On and Note Off messages.

In all other cases, Trails sends MIDI CC messages, allowing the axis to be used as a continuous modulation source.

MIDI clock

Trails can transmit MIDI Clock over USB MIDI. This allows external MIDI devices and software to remain synchronised to Trails' internal clock.

TRS MIDI I/O

With TRS MIDI, Trails can be integrated directly with external MIDI hardware without requiring USB connectivity. There are two types of MIDI TRS connector: A and B. A is now adopted as a standard by the MIDI Association. Type B is still used by some manufacturers, notably Arturia and Novation. Trails lets you choose which type you want to use by setting the appropriate jumpers on the rear side of the main and breakout modules. You can set the required MIDI type for in and out independently.

TRS MIDI input

TRS MIDI input is available via configurable jumper settings on the rear of the module. The MIDI interface shares the connector with an analog input:

• INPUT 4 can be reassigned as a TRS MIDI input.

Refer to the rear-panel jumper configuration diagram for the appropriate settings.

TRS MIDI output

TRS MIDI output is available via configurable jumper settings on the rear of the module. The MIDI interface shares the connector with a gate output:

• OUTPUT 4.G can be reassigned as a TRS MIDI output.

Refer to the rear-panel jumper configuration diagram for the appropriate settings.

Updating the module

A firmware update for Trails is available. Updating is done through a browser-based tool, so there is no software to install: connect Trails to your computer with a USB-C cable and follow the instructions in the browser. The process uses WebMIDI, so it requires a Chrome browser.

Find the tool and the latest firmware releases at bela.io/upgrade-trails.

Troubleshooting

Module not behaving as you expect? Write to info@bela.io and let us know what you are encountering, including your firmware version, which is shown in the menu. We can guide you through diagnostics for any hardware issues.

We also welcome feedback and suggestions for future firmware updates. Trails is designed to evolve, and much of what has shaped it so far has come from people using it in their own setups. If something feels like it could be improved, or there is behaviour you would like to see added or changed, we would like to hear about it. We cannot promise that every suggestion will make it into a release, but all of them are read and considered.

Hardware

Specifications

Electrical and mechanical specifications for the Trails module. Connector counts and functions are listed in Interface summary, above.

Assembly

Before connecting anything, make sure your case is powered off.

Connect the 24-pin ribbon cable between the breakout board and the main module, then connect the 16-pin ribbon cable to the main module and to your case's power supply (ensure correct orientation of the power cable on your power supply). Once both cables are in place, mount the two modules wherever you like in the case: they do not need to be next to each other.

Changing for the 1U panel

If you want to use the 1U 22HP panel, the breakout board is transferred from its 3U panel onto the 1U one.

You will need a nut driver. The jack sockets use Befaco Bananuts, and many standard nut drivers fit them.

Pull the knob off the shaft, then unscrew the nuts from all of the jack sockets and remove the 3U panel. Place the 1U panel over the board, screw the nuts back on, and refit the knob. The breakout can then be mounted in a 1U row.

Tighten the nuts until they are just snug. Panel-mount jacks are easily damaged by overtightening, and a jack that has been forced can crack its solder joints or twist on the board.

Mounting in a skiff

If you want to mount Trails in a skiff, for example a 4MS pod, it may be necessary to remove the locking tabs from the 24-pin ribbon cable that connects the main PCB to the expander board. This can be done easily with a pair of pliers.

On batch 1 and 2 modules, the MIDI board protrudes from the back of the case and must be removed to fit some skiffs. Once it is removed, set the rear jumper as shown below to continue using input 4.

We recommend you use the power cable provided. Longer power cables or long extension cables from your Eurorack power supply may have unexpected effects on the CV outputs.

Warranty

Trails is covered by a two-year warranty against defects in materials and workmanship. This does not cover damage caused by incorrect use, including but not limited to incorrect power connection, excessive voltage, or exposure to extreme heat or moisture.

The warranty covers replacement or repair. Contact us before returning a module: info@bela.io.