Bela Trails Polyphonic Touch Controller

We say...

We've been looking forward to this one ever since we got a preview at Superbooth 2025! The brains behind Gliss have taken the concept into two dimensions and the results are astonishing. Gesture recording has never been so powerful.

Manufacturer's description

Trails is a polyphonic touch recorder that turns gestures into music. It lets you compose melodic, harmonic, rhythmic, and control data at the same time, by recording the movement of your fingers. These recorded gestures can then be transformed in space and time, intuitively generating contrapuntal and polyrhythmic relationships between its four channels.

Trails generates both control voltage and MIDI information, so it can control all kinds of hard- and software instruments, while gestures can be saved into 16 scenes for easy recall and live performance. These signals can be used for smooth, continuous parameter shaping, or can be quantised for generating melodic, tempo-synced information.

Trails breaks new ground in both Eurorack and the broader controller space. It builds upon the success of its predecessor, Gliss, which proved how valuable recordable touch control is for expressive and immediate sounds. Trails expands the concept into new dimensions with a polyphonic approach that gives us an exciting new way of making music.

Compose with movement

Trails has four channels, each with X and Y position outputs following your finger’s movement across the touch surface, plus a gate for rhythmic and timing information. Each channel can store gestures up to 40 seconds long, allowing you to draw anything from non-repeating, evolving signals, to custom LFO and envelope shapes. These signals can be recorded individually or across multiple channels, letting you control a single parameter, all twelve at once or any combination of your choosing.

With Trails, all your gestures can change back and forth from a continuous curve to a stepped and quantised signal. This turns your gestures into melodies and rhythms at the touch of a button, which can then be tuned using a bank of premade scales or to your own custom, two-octave design. The Touch Bar then allows you to selectively slew your gestures, slowing them down and smoothing them out – or divide your rhythms with Euclidean divisions. The X and Y outputs also have their own fully customisable voltage ranges, so whether you’re controlling a melody or a continuous parameter, you’ve got the perfect range of touch for the job.

Transform your gestures

Recording your gestures is just the beginning; Trails gives you the chance to further manipulate them in dynamic and fascinating ways. Making use of its two-dimensional pad and multi-touch capabilities, Trails invites you to create new relationships between your recorded gestures while maintaining their shape and original characteristics, leading to musically meaningful variations.

Rotate your gestures around a set origin, pinch them into a dynamically sizeable box or offset your signals, pushing them towards a single point. Crucially, these transformations can themselves be recorded, providing gestural control of your gestures. These recordings can also be erased non-destructively, making them useful for momentary variations. Transformations can also be applied to channels selectively, so you can adapt one, two or three gestures while leaving the others untouched.

Bend time

Trails’ transformations aren’t limited to the spatial domain—your gestures can also be manipulated temporally. They can be viewed on a timeline where you can use touch to actively control their playback position, set looping points or nudge them backwards or forwards in time. This opens up a wealth of possibilities for precisely controlled rhythmic phasing, dynamically shifting loops, touch-controlled resetting and much more.

The Touch Bar takes these manipulations to another level. Controlling one or any combination of channels, it allows you to slow down or speed up the playback speed of a gesture.

Morphing macros

What if you prefer to control signals with a set of faders rather than gestures? Trails gives you multiple banks of eight touch-controlled faders, providing macro control for eight parameters at once. Precisely dial in your faders then move on to the next bank to create a chain of preset values, which can then be selected at any time via the Touch Bar.

While immediate changes are useful for creating sudden, large-scale changes in sound, Trails lets you smoothly interpolate from one fader bank to the next, all controlled with your finger on the Touch Bar.

Choose your layout

Every Eurorack user has different wishes and needs for where the in- and output jacks should be located on the module. Trails takes the unique step of providing a breakout module that can either be placed on the left, right or upper side of the module, letting the user choose the setup that suits their system.

Features

• Record gestures of up to 40 seconds across four channels
• Simultaneously generate melodic, harmonic, rhythmic and control signals
• Control MIDI-compatible (hard- or software) and Eurorack devices
• Generate two touch-controlled CV signals (x and y), plus a gate signal, per channel
• All CV and gate signals can be quantised to generate melodic, tempo synced information
• Record gestures individually or on multiple channels at a time
• Dynamically offset the playback of one gesture against another
• Slew x and y values with the Touch Bar
• Transform recorded gestures with rotation, pinch and offset
• Non-destructively record and undo transformations
• Dynamically control the playback position and loop in-out point of four gestures
• Touch control of gesture playback speed
• Interpolate between multiple banks of eight touch faders
• Store up to 16 scenes
• Divide and multiply clocks per channel

Inputs

• 4 × CV inputs (one per channel, reset and modulation)
• 1 × Clock input

Outputs (via breakout)

• 8 × CV outputs (X/Y per channel)
• 4 × Gate outputs (one per channel)
• MIDI TRS

Interface

• 85 × 85 mm multitouch capacitive touchpad with shine-through LEDs
• 10 × 85 mm capacitive slider with shine-though LEDs
• 6 illuminated control buttons (record, play, quantise, S&H, undo/redo, shift)
• 4 channel select/mute buttons
• 4-position mode selector
• USB-C port on back for USB MIDI

What's included

• Power ribbon cable
• Alternative 1U faceplate for output breakout
• Mounting screws