Chapter 11 - Bass Mode¶
The Bass Track is UNA's third independent voice - a bassline that follows the same chord chain as the Melody Track but with its own parameters, its own captures, and its own way of generating variation.
The editing surface reflects what bass parts actually do in music. Where Melody gives you per-step precision via the Stepper, Bass gives you Improv - a probability-driven system that lets a captured bass line vary without ever drifting out of key.
Getting in and out¶
From Performance Mode, press BASS. If Bass isn't already the active track, the first press selects it and a second press opens the mode (Chapter 6).
UNA enters Bass Mode and the CONTROL buttons are assign as:
| LOAD | IMPROV | PARAMS |
| CAPTURE | PLAY / STOP | BACK |
- LOAD - seed a bass pattern from one of 50 presets, browse by category, or have UNA generate one for you.
- IMPROV - open the Improv page where the 9 Improv parameters live.
- PARAMS - track parameters menu, including the Lock controls.
- CAPTURE - record a bass line from MIDI input.
Press BACK at any time to return to Performance.
The eight PARAMETER Knobs are live, same as Melody Mode - adjust track parameters directly without entering a sub-mode.
Why there's no Stepper here¶
The Melody Track has a Stepper. The Bass Track does not - and this is a design choice, not a feature gap. Melody is where you want per-step precision. Bass is where you want a strong line that can vary a little each pass - locked enough to be a groove, varied enough not to feel mechanical.
The Improv system gives you that variation by playing odds: chance of a pitch shift, chance of an octave jump, chance of a layered note, all gated by a master probability. You set the rules; UNA improvises within them.
LOAD - Seeding a bassline¶
Press LOAD from Bass Mode and you arrive at Bass Presets, where you can choose a starting bassline.
| Function | What it does |
|---|---|
| PRESET | Browse a curated library of 50 named patterns. CONTROL Knob scrolls. |
| CATEGORY | Filter the library by genre (ALL / ROCK / POP / FUNK / LATIN / JAZZ). CONTROL Knob picks the category. |
| GENERATE | Procedurally generate a pattern. CONTROL Knob picks a seed number (0–999); the current category biases the generation toward that style. |
| APPLY | Commit the previewed pattern to the Bass Track. |
| CANCEL | Discard and return to Bass Mode. |
The three modes share a single preview - whatever you've got selected is auditioning live, so you can hear it before you commit. The PARAMETER Knobs are still active for live track, the preset only sets the pitch and octave content, leaving the playback shape under your control.
A note on what a preset is. Bass presets are pitch sequences - root walks, pedal points, climbs, syncopations. They don't carry gate or velocity values, so each preset will play in whatever rhythmic feel you've set on the Bass Track's own parameters. That means a "Walking Jazz" preset and a "Rock Driver" preset can be loaded into the same gate/velocity setup and you'll just hear them as two different walking lines, not as two different productions.
The 50 presets are organised across five genre categories:
- ROCK - ROOTS, POWER, DRIVE, STOMP, CHUG, RIFF, ANTHEM, GALLOP, DROP, CRUNCH
- POP - SIMPLE, GROOVE, SWING, UPBEAT, BOUNCE, STEADY, POCKET, SMOOTH, CLEAN, BRIGHT
- FUNK - FUNKY, TIGHT, SYNCOPATED, PERCUSSIVE, GROOVING, PUSHING, SHUFFLED, SLAP, POPS, SNAPPY
- LATIN - CLAVE, BOSSA, SAMBA, MERENGUE, MAMBO, TANGO, RUMBA, CUMBIA, GUAGUANCO, MONTUNO
- JAZZ - WALKING, PEDAL, COMPING, WALKING2, SPARSE, FLOATING, CHROMATIC, OPENSTRING, BOHEMIA, BLUES
CATEGORY mode lets you stay within a feel; ALL disables the filter and lets you browse the whole library.
Generate is the random option. UNA's pattern generator uses a category-biased random algorithm - pick LATIN and turn the CONTROL knob, you'll get LATIN-flavoured patterns (more syncopation, more chromatic notes); pick ROCK and you'll get root-heavy steady lines. The seed number is just a label for the random state, so writing it down means you can come back to the same generated pattern later.
IMPROV - variation by probability¶
Press IMPROV from Bass Mode for the dedicated Improv configuration page. This is where the nine Improv parameters live, with the most important one - PROBABILITY itself - on the CONTROL Knob.
The screen layout reflects how Improv is wired:
- CONTROL Knob → PROBABILITY (0–100).
-
This sets how often a deviation happens. At 0, nothing varies - the bassline plays exactly as captured. As you raise it, more steps are deviated. PROBABILITY is rolled independently for each parameter, so the eight parameters don't all land on the same steps. Turn this knob first; everything else is secondary.
-
PARAMETER Knobs 1–8 → the eight Improv parameters.
- Each knob sets how much its parameter deviates - the size of the move, not how often it happens.
The nine parameters:
| Parameter | What its Amount controls |
|---|---|
| PROBABILITY | The master gate - how often any deviation fires (lives on the CONTROL Knob) |
| PITCH | How far the note can drift to nearby scale degrees |
| GATE | How much the gate (note length) varies |
| VELOC | How much the velocity varies |
| SLICE | How much extra subdivision (ratchet) is added |
| OCTAV | How far the step can jump in octaves |
| CHAN | How far the MIDI channel shifts (for split-synth setups) |
| DELAY | How much swing / timing offset is added |
| LAYER | How many extra notes are stacked above the played note |
How a deviation is applied. Each step, every parameter independently rolls against PROBABILITY to decide whether it deviates. When it does, that parameter's own knob - its Amount - decides how far.
Amount doesn't scale the move evenly; it shapes it. At low settings the moves are small and gentle, a subtle humanise that can't make a big jump. As you raise Amount they grow and increasingly favour the parameter's extremes, so high settings reach the full range often - but never every time, keeping the result musical rather than pinned to the maximum.
Creating swing. DELAY adds a random timing offset to the steps it fires on, and, like every other parameter, it's gated by PROBABILITY.
- Set the Delay Type parameter to SWING and DELAY only offsets every other step, giving a random, swing variation.
- In the default ALL mode it can nudge any step.
Press BACK to leave the Improv page.
The Bass mode display shows the per-step variations being applied (during playback), with colour coded markers on each affected step, so you can see the improv working in real-time.
Capturing a bass line¶
Press CAPTURE from Bass Mode for Bass Record - the same capture model as the Melody Track, applied to the Bass Track.
The mechanics are identical to Melody Record (see Chapter 9), so we won't repeat them here.
The pre-record control layout:
| Function | What it does |
|---|---|
| QUANTIZE / TIME | Set snap grid (or note length in Step Input). |
| METRO | Toggle the click. |
| OPTIONS | Open Bass Record Options. |
| ARM | Prime capture; becomes STOP once recording. |
| APPLY | Commit (after STOP). |
| BACK / CANCEL | Exit without committing. |
The same after-stop loop applies: PLAY to audition, RETRY to start again, OPTIONS to retune capture settings, APPLY to write the captured phrase into the Bass Track.
A safety detail: as with Melody capture, applying a fresh Bass capture resets the Lock parameters to OFF - so what you just played is what plays back, uncoloured by old Lock settings.
Track Parameters¶
Press PARAMS to open the Bass Track parameters menu. The categories are the same as elsewhere on UNA, with one key difference: instead of Stepper categories, the Bass Track has an IMPROV category (since bass evolves via Improv rather than per-step editing).
- PRIMARY - the parameters that affect individual notes and steps: OCTAVE, CHANNEL, DELAY, LAYERS, GATE, VELOCITY, PITCH, SLICE, plus the toggle-style parameters MODE, DELAY TYPE, VOICE MODE, SLICE TYPE.
- SECONDARY - the parameters that affect the sequence as a whole: STEPS, ROTATE, JUMP, DIRECTION, TIME, MUTES, ACCENTS.
- LOCKS - OCTAVE, NOTE, CHORD (the same override layer as the other tracks - see Chapter 8).
- IMPROV - the 9 Improv parameters, the same values you also set on the dedicated Improv page via IMPROV on the main Bass Mode screen.
Quick shortcut: you don't have to scroll to reach a parameter. Press a PARAMETER Knob (1–8) to jump the menu highlight straight to that knob's parameter - press a PARAMETER knob for the primary, or press and hold CONTROL + a PARAMETER knob for the secondary.
For a full reference to every parameter - what it controls, its range, and its default - see Chapter 7 - Track Parameters.
The Lock controls¶
Bass has the same Lock controls as the other tracks:
- LOCK > OCTAVE pins the octave
- LOCK > NOTE overrides the root pitch class
- LOCK > CHORD overrides the chord intervals the bass picks from.
Chapter 8 has the deep dive; everything there applies identically to Bass.
Lock-param edits take effect immediately (the change happens on the next tick, not the next chord change), so you can tweak Lock settings while the bass is playing and hear the result in real time.
Worked Recipes - for Bass¶
The "get a bassline in 10 seconds" recipe. From Performance, BASS → LOAD → press CATEGORY, rotate to LATIN → press PRESET, rotate to BOSSA. Listen - you're auditioning. APPLY. The Bass Track is now playing a bossa.
The "make it breathe" recipe. From the bassline above, press IMPROV. Set PROBABILITY (CONTROL Knob) to about 40 - that's roughly how often a step will deviate. Set PITCH (Knob 1) to 20 for a small, gentle drift. The bass will start sliding to nearby scale note on around 40% of its hits - still grounded, but no longer mechanical. Raise PITCH for bigger leaps, PROBABILITY for more frequent ones.
The "play your own" recipe. BASS → CAPTURE. Make sure INPUT MODE in OPTIONS is Realtime. ARM. Play the bass line on your keyboard. STOP. APPLY. The Bass Track now plays what you played; apply Improv on top of it for variation.
The "pedal-point" recipe. Build any chord chain. Enter BASS → PARAMS → LOCK → NOTE → set to D (or whichever pedal note you want). The chord chain moves; the bass stays anchored on D regardless; a "Pachelbel-style" pedal harmony in seconds.
What's next¶
Chapter 12 (Modulate) pairs well with Bass: a Modulate slot pointed at one of the Improv parameters will sweep that value up and down over time, giving you a bassline whose variation grows and recedes naturally across a section. Chapter 8's Lock deep dive is also worth a read.