# Param sequencer

Per-step parameter lanes, Draw mode, Blend, lane tabs, and how panel knobs mix with sequence overrides.

**Param Seq** is RUB’s automation lane system: each pattern can hold several parameter sequences that write values step by step. Use it for filter moves, mix rides, Tune gestures, FX toggles — anything in the [parameter catalog](/docs/parameters) marked **Lane = yes**.

Enter Param view with **Tab**, the Param ear, or the Param tab on the [homepage tour](/#instrument).

![Pattern / Param switch](figure:view-param)

## What a lane is

A lane is one `ParamId` on one pattern: 16 step values plus an “active” bit per step. Values use the same real units as the panel (see [Parameters](/docs/parameters)).

- **Written** steps store a level
- **Unset** steps hold the last written level (latch) — they are not “zero”
- A lane can be **disabled** (muted) without deleting its data

Patterns with any installed lane count as occupied (glow) even if the note grid is empty.

## Lane chrome

### Picker and add

![Lane picker](figure:param-picker)

![Lane picker menu](figure:menu-lane-picker)

![Add lane](figure:param-add)

![Add-lane menu](figure:menu-param-add)

| Control | Role |
| --- | --- |
| **Lane picker** | Choose which installed lane you are editing |
| **+** | Add another sequenceable parameter (blocked when the pattern is full or the param is already present) |

BPM and Lane Blend themselves are not lane targets (tempo / blend are song-level). Delay Sync is also excluded from lanes.

### Tabs

![Lane tabs](figure:param-lanes)

![Lane tab menu](figure:menu-lane-tab)

Each installed lane gets a tab. **Right-click** a tab:

| Menu | Effect |
| --- | --- |
| Enable / Disable | Mute the lane while keeping values |
| Clear | Wipe all step writes on that lane |
| Remove | Free the slot entirely |

### Draw

![Draw](figure:param-draw)

Toggle **Draw**, then click-drag across the bars to paint levels in one stroke. Turn Draw off to click individual steps or open the inline editor.

## Step bars

![Param steps](figure:param-bars)

| Action | How |
| --- | --- |
| Write a step | Click a bar (or drag in Draw mode) |
| Nudge level | **↑** / **↓** (Shift = ×10) |
| Clear step | **Del** / **Backspace** |
| Inline edit | Double-click / edit readout where offered |

Scale depends on the parameter:

- Continuous knobs use their normal range
- Mix reads as OSC A ↔ B
- On/off and some bipolar params (e.g. Tune) use a mid-origin display

While playing, automatable panel knobs show the live lane overlay so you can see sequence vs panel at a glance.

## Blend

![Blend](figure:param-blend)

**Blend** (0…1, default full seq) crossfades:

- **PANEL** (left) — respect faceplate / MIDI knob positions
- **SEQ** (right) — lean on Param Seq writes

It appears when the current pattern has lanes. Right-click Blend to [MIDI-map](/docs/midi-learn) it. `lane_blend` is stored in the song JSON document.

## Clipboard and patterns

In Param view, **Cmd/Ctrl+C / X / V** copy, cut, and paste *lanes* for the selected pattern (not notes). Pattern-menu **Param** section offers the same. **Cmd/Ctrl+D** still duplicates the whole pattern (notes + lanes) into the next empty slot.

Right-click a pattern LED for Transpose (notes), note clipboard, param clipboard, or **Clear all**.

## Workflow tips

1. Add **Cutoff** or **Env Mod** lanes first — filter motion is the classic Param Seq move.
2. Keep Blend mid-way while designing so you can still grab the panel knob.
3. Disable a lane to A/B a sequence without losing it.
4. Dump the song with [Song JSON](/docs/song-json) if you want an AI to author `lanes` arrays for you.

## Related

- [Oscillators](/docs/oscillators) — Tune / Mix lanes and sync
- [Sequencer](/docs/sequencer) — notes, accent, slide, chain, capture
- [Parameters](/docs/parameters) — which `id_str` values are lane-capable
- [MIDI map](/docs/midi-learn) — perform with CC while lanes run
- [Panel overview](/docs/panel-overview) — faceplate map