LH Spectral Palette Sketchpad

Unit library

Single units saved by name. Place puts a copy at the cursor (or the play point).

Library file

One file holds your saved units and your Sound Lab presets, to keep or to carry to another sketch. Sketches already carry both.

Sketches on this iPad

Save keeps sketches here. Send to iCloud when you want one on the Mac.

Sound Lab

LH Breath · ported from REAPER

The iPad plays a close copy of each REAPER synth, so expect small differences. The REAPER sound is the real one.

Press and hold a pad, or hold its key on the keyboard (1–0, Q–Y); let go to hear the release. − / = octave, Space test phrase, Esc closes. Tap any number to type a value. Notes come from the score's field.

How to use the sketchpad

Drawing and selecting

Pencil stroke: draws a band (Band tool). Pressure = loudness, tilt = sine ↔ noise.
Quick Pencil tap: selects the unit under it instead of drawing.
Press and hold: on a unit with the Pencil picks it up; drag to move it.
⌘ + Pencil: selects in any tool; keep dragging to move. ⌘⌥ + drag moves a copy.
Finger tap: selects. Finger drag on the selected unit moves it. Fingers never draw.
Impulse: Pencil tap stamps a chord burst from the field (called Splash before; the Mac calls it Impulse too).
Block: drag a rectangle with the Pencil: the field lines inside it become a chord over that time (as on the Mac). Entry (chord, arpeggio, fan, strum) is in Settings.
Pulse: drag across time with the Pencil: a train of short notes at that pitch (end higher or lower for a glide). Gaps in ms, accelerando, length, jitter, accent and partials are in Settings (as on the Mac).
Line: draw with the Pencil: one voice that glides along the line (UPIC-style).
Cloud: drag a rectangle: a seeded scatter of notes between its edges. Density, note lengths, fade and a new seed are in Settings.
Layers: in Settings: tap a layer to draw on it (it is always shown in front). ● ◐ ○ = full · in the background · hidden. M = mute. Background all / Show all. Faded layers can't be selected.
✥ Select / move: switches the Pencil and trackpad from drawing to selecting and moving units; tap it again (or press S) to go back to drawing.
Settings: Unit | Score: Unit shows only the selected unit (or the brush for the next one); Score holds the global settings — sketch, field, duration, sound, layers. ⇧2 switches; selecting a unit or a drawing tool opens Unit.
Pulse bend: select a pulse (Select or Shape): drag its end points up or down, drag a ⊕ to add a bend point, double-tap (or ⌥-tap) a bend point to remove it. Points snap to the field; ⌘ = free pitch.
Zoom: two fingers on the score: spread / pinch = zoom in / out, move = scroll. Hold ⌥ to zoom pitch only, ⌘ to zoom time only. On the trackpad: ⌘ + two-finger scroll zooms time, ⌥ + two-finger scroll zooms pitch, plain two-finger scroll moves around (pinch also works where the browser lets it through). Keys: ] [ zoom time in / out, ⌥] ⌥[ zoom pitch, 0 = whole score — they zoom about the cursor (or the selected unit) and bring it to the middle of the screen. Or drag on the axes: the time ruler up / down = zoom time (then sideways = scroll); the pitch labels at either side up / down = scroll pitch, right / left = zoom pitch.
Notes on / off: select a block or an impulse: its notes show as chips in Settings › Unit. Tap one to switch it off (it stays as a faint ghost, silent) or on again. ⌥-click a note on the score does the same.
Chord (O): drag across time to make a chord. While editing (Enter, or tap the chord with the Chord tool) tap in its column to add a note on the semitone grid, tap a note to remove it, drag a note to move it (⌥ = cents, ⌘ = free). Or type the notes in the panel: C3 E♭3 G3+14, MIDI 60.5, 440hz. The top / bottom handles stretch the spread (top keeps the bass, bottom keeps the top); dragging the chord up or down transposes by semitones (⌘ = free). Entry (chord, arps, fans, strum), velocity and envelope as for a block.
Start / end: in Select (or with ⌘, or a finger on a selected unit) drag a unit's left or right edge: the other end stays put and the content stretches to fit. With a group or several units selected, the whole selection stretches. ⌥-drag crops instead: the content stays in place (one unit).
Shape: drag the four corner handles; notes glide to follow the outline.
Line / cloud points: select a line or cloud (Shape or Select) to see its points: drag one to move it, drag a ⊕ to add one, double-tap (or ⌥-tap) to remove one. In Shape, drag a cloud's edge line to move the whole edge. Line points snap to the field; hold ⌘ for free pitch.
✎ Annotate: Write, Arrow, Circle, Note and Erase. Annotations sit on the score and make no sound.
Note icons: tap one to read or edit the note. Select a unit and press N (or Add note) to give it one.

Envelope panel (key 1)

Tap the curve: adds a point; keep dragging to place it.
Double-tap a point: deletes it (or tap it, then ⌫ / Delete point).
Tap between points: picks a segment; drag its ◇ up or down to bend it.
Draw freehand: starting away from the curve replaces that section.
● Record: plays the unit once while you ride the fader.
Reduce points…: slide down to thin the curve; the ends stay.
Shapes: Save shape… stores the envelope; tap a shape to load it.
Whole chord / a note: shape the unit, or give one note its own envelope.
Loudness · Pan: switch the lane between the loudness envelope and the unit's pan (top = right, middle = centre, bottom = left). Pan is drawn and edited the same way.
♪ Sound Lab (3): in Settings: craft sounds from the REAPER synths (LH Breath so far). Hold the pads to play; moving a control on a REAPER preset makes your own copy. “Use on this layer” puts it in the score (Sound: Sine + Sound Lab presets).
LFO: adds a plain sine tremolo across the unit: shape, cycles, depth. More ▸ has the rest (Hz, phase, skews, tilt, baseline, soft edges, presets, Bake).
Section: then drag across the lane to put the LFO on part of the unit (⇧-drag with a keyboard). Drag the [ ] tabs at the foot of the lane to adjust it.

Playing

Space: play or stop from the teal start marker.
● Tap a rhythm…: select a pulse; in Settings tap the pad (or press T) in rhythm, then Done. Stretch the unit to compress or expand the rhythm.
▶ Unit · ⇧Space: play just the selected unit once. New units don't play by themselves, so you can edit them first.
Tap markers (⇧T): tap a structural rhythm with P (or the Tap pad); each tap is a time point. The first tap is TP0 at the play point, then TP1, TP2… Press Space first to tap along with the score (taps land at the playhead). Return = done, Esc = cancel. Settings › Score has the button.
Regions / markers: the two slim lanes above the score. Tap the markers lane to add a marker (⇧M at the pointer); drag in the regions lane to make a region (⇧R from a time selection). Drag to move, drag a region's ends to resize, double-tap to name, ⌥-tap or ⌫ to delete. Saved with the sketch, listed in the Obsidian notes, and written to REAPER on Commit.
Time ruler: tap or drag it to move the start marker. , . nudge it, Return goes to 0:00.
Duration: in Settings. Changing it stretches or contracts the whole score (untick "Stretch" to keep material where it is).
L: loop (solo) the selected unit, or just the chosen note.
Silent switch: turn it off on the iPad to hear the preview.

Keyboard

B I K P U C V E H A: Band, Impulse, Block, Pulse, Line, Cloud, Select, Erase, Shape, Annotate
S: switch between drawing and selecting / moving (under the left hand; M works too)
N: note for the selected unit
⌘C ⌘X ⌘V ⌘D: copy, cut, paste, duplicate a unit
/: split the selected unit at the pointer (clouds and pulses keep their notes)
⇧-drag the time ruler: time selection: two lines across the score (drag a line on the ruler to adjust). The bar at the top: Remove time (⇧⌫ — what's inside is deleted, units crossing the lines are cut, the rest closes up), Insert silence of that length at the left line (⇧I), Clear (Esc).
⇧I: insert silence at the pointer: a prompt asks the length (mm:ss:hh). Settings › Score › Insert silence… does the same at the play point. Everything later moves right; units crossing the point are split.
⌥⌘C ⌥⌘V: copy, paste just the envelope
⌫: delete the selected point, or the selected unit
⇧-click · drag a box: select several units: ⇧-click adds or removes one; in Select (V), or with ⌘ held, drag a box over empty score. ⌘A selects all.
⌘G · ⇧⌘G: group the selected units / ungroup. A group selects, moves, copies, duplicates, stretches and transposes as one (panel › Reshape), and saves to the unit library as one entry.
⌘Z ⇧⌘Z: undo, redo
← → ↑ ↓: move the unit in time (0.1 s) or pitch (semitone); ⇧ for 1 s / octave
R: record the envelope
1 · 2 · F: Envelope panel, Settings panel, full screen
⌘S: save the sketch
Esc: close, deselect
?: this help

Saving

Notes, writing, arrows and circles are saved in the sketch file, so they travel to the Mac with the score. Export notes for Obsidian (in Settings) saves them all as Markdown, each note with the date and time it was written, plus key data and a picture of the whole score.

Your work is kept on the iPad as you go, but Save writes the sketch file, which is the real copy. Save to iCloud Drive to reach the Mac. The red Unsaved dot shows when there are changes since the last save.

Note

Name this sketch

The date and time are filled in. Change the name if you like. Later saves keep this name and don't ask again; rename it under Settings › Sketch name.

Copy this sketch

Saving a file isn't available in this view. Copy the text below and paste it into a note or a text file called sketch.json.