Glossary

Short definitions for words used in ARC-24 and this guide.

A

Active loop — The loop you're editing and playing on the main screen right now.

ARP / Arpeggiator — ARC-24's built-in arpeggiator (labeled ARP in the app). 25 presets grouped into Slow & Sparse, Melodic, Driving, and Dark, chosen from a picker sheet with contour previews. Tap a pad in Notes mode to loop an arpeggio from that root, transposed in key. See Arpeggiator (ARP).

Arpeggio — A repeating pattern of notes in rhythm, stepping from a root pitch — what the arpeggiator plays.

Atmosphere (track) — Per-track stereo atmosphere in Mixer → FX → Atmosphere: Space Send (real Freeverb tail), Chorus, and Tape Wow. Processing order: chorus → Freeverb → tape → width. Dry level unchanged for the send; wet tail and modulation added on top. Not the same as Tone reverb. Applies to synth, sample, and drum tracks.

Arm / Arming — Turning recording on for the selected track (synth, sample, or drums). Shown with a red record indicator.

Arrangement — The ordered list of sections that makes up your full song for playback and export.

B

Bloom — Per-track Motion feature (Mixer → FX → Motion): live pad hits temporarily open that track's synth filter (and can push Atmosphere sends). Triggers only on the track that received the hit.

BPM — Beats per minute — your song's tempo (default 88).

C

Character (track) — Per-track texture, air, width, and warmth (Mixer → FX → Character). Tape wow and chorus live under Atmosphere; filter motion under Motion.

Chop (Sampler) — Session-only tool on the Sampler Pads layout (right side of the extras row). Tap a loaded pad to loop-preview the source; tap empty pads in order to slice shared audio into new pads (arm start, next tap ends slice). If the preview loops before you finish, the armed slice auto-saves through the source trim end. Mutually exclusive with Clear pad and Erase. See Sampler.

Chorus (track) — Stereo chorus/shimmer in Mixer → FX → Atmosphere. Applies to all instrument types via the track post chain.

Clear pad mode (Sampler) — Extras-row dashed-square icon on the Sampler screen. Tap a loaded pad to remove its sample from the pad pool — same as Clear on the pad settings sheet (Edit mode), not loop erase. Mutually exclusive with Chop and Erase. Session-only.

D

Downbeat — The first beat of a bar. Live loop switches from the Mixer wait until the downbeat at the end of the current cycle.

Drum kit — A folder of samples under DrumMachines/ in the app. Pad order and labels come from filenames like 1_Kick_1.wav (not from kick/snare type prefixes). Kits are chosen per drum track from the performance kit pill or the track's Drum Settings — both open the same kit picker sheet.

Drum track — A track (T1–T8) whose recorded content is drum hits. Created automatically by recording in Drums mode on an empty track. Each drum track has its own kit, pad tuning, and the full channel chain (EQ + Mixer → FX). Quantize defaults on (1/16 at 100%) when a track becomes a drum track.

Drum pad index — The position of a pad in the sorted kit list (first pad = 0). Loop recordings store this index, not the sample filename.

E

Erase mode — Hold pads while the loop plays to remove recorded notes, drum hits, or sampler loop hits. On Sampler, Erase does not remove the sample from a pad — use Clear pad (extras dashed-square icon) or Clear on the pad settings sheet for that. Mutually exclusive with Chop and Clear pad.

Export filename — Name from your song title; loop exports add the loop name (e.g. Dusk - Verse.wav). Use Share File to save the bounce outside the app.

G

Grid editor — Full-screen piano-roll view of the selected track's recorded loop, opened from the extras-row grid button (visible once the track has recordings). Hold-and-drag hits to move them with a snap grid, resize synth notes and chords from their right edge, or delete them — while the loop keeps playing. Its Undo only steps back grid edits, never a recording pass.

H

Hold mode — Extras-row toggle in Notes mode. Per track on/off; each pad tap latches that note on or off. Other tracks keep Hold state and latched notes when you switch. While armed and recording, latches auto-clear after one loop cycle. Unavailable while ARP or Pulse is on. Session-only; not saved with songs. See Hold mode.

Humanize — Adds slight random variation to timing and loudness on playback so loops feel more natural.

I

Insert FX (track) — Per-track creative processor rack on T1–T8 (synth, sample, or drum tracks), edited from Mixer → FX: resonant filter, compressor, gate, distortion, bit-crusher, ring mod, flanger, and BPM-synced delay. Saved per loop.

K

Keys mode (Sampler) — Plays one source sample across all sixteen pads. On the Keys header, tap Set Source then a loaded pad to choose the sample; set the root with Set Root (Pick root… → tap a pad). Scale mapping steps by loop key/scale; Chromatic steps by semitones. Root pad shows a dashed ring. Pitch is playback-rate (not time-stretch). Root assignment is session-only (not saved with the song); Keys mapping and source pad are saved per loop.

Keys mapping — Sampler Keys layout pitch mode: Scale (diatonic steps from loop key/scale) or Chromatic (semitone steps). Set on the Keys header (Perform mode).

L

Loop — One scene in your song: its own length, key, recordings, sounds, and mix. A song can have many loops.

Loop scene — Switching between loops during a performance (using the Mixer strip).

M

MIDI channel — In Setup → MIDI, Omni accepts note messages on any channel 1–16; a fixed channel ignores all others.

MIDI input — External USB or Bluetooth controllers. Off by default; configured in Setup → MIDI. Notes, Drums, and Sampler modes (not Chords). See MIDI input.

Motion (track) — Per-track slow filter motion and Bloom (Mixer → FX → Motion): Motion Amount, Motion Rate, Bloom toggle/amount. Affects the synth filter on that track; Bloom fires only for live hits on that track. Saved per loop.

Pad Base Note — In Setup → MIDI, the MIDI note mapped to pad 1 for Drums and Sampler; consecutive chromatic notes map to the rest of the grid.

N

Network MIDI (Session 1) — Apple's virtual network MIDI endpoint on iOS. Listed under Connected Devices even without a physical controller; used for Mac ↔ iOS network MIDI when configured in Audio MIDI Setup.

O

Oscillator — The synth's sound source — a repeating wave (sine, triangle, saw, or square). Each synth voice has up to two: Osc 1 is always on; Osc 2 is an optional layer with its own shape, level, detune, and octave. See Track sound design.

Overdub — Recording a new part while previous parts play back.

P

Pad — A touch control in the grid — a note, chord, or drum hit.

Preroll — A four-beat count-in before recording starts.

Q

Quantize — Pulls recorded notes toward a steady grid on playback. Strength controls how tight the snap is.

R

Recipe — A preset sound for a synth track.

Record offset — Fine-tuning in Setup to align recordings when using Bluetooth headphones.

S

Sampler — Fourth performance mode: sixteen song-wide pads for user audio (import or mic record). Any track T1–T8 becomes a sample track automatically when you record sample hits on it; hits record on the armed track's loop through that track's mixer/FX. Pads are assigned and edited on the performance screen (Edit mode). Pads or Keys layout per track; Scale/Chromatic Keys mapping. See Sampler.

Sampler pad index — Pad 0–15 in the 4×4 grid. Loop events store this index like drum hits.

Scale — The set of notes used for the pad grid (Major, Minor, Dorian, and others).

Section — One row in your arrangement: a loop plus how many times it repeats (×1–×4).

Solo — When any channel is soloed, you only hear the soloed tracks.

Song — Your saved project file.

T

Tape Wow (track) — Slow pitch/flutter modulation in Mixer → FX → Atmosphere. Applies to all instrument types via the track post chain.

Tone reverb (track) — Short color reverb in Mixer → FX → Reverb (Tone) (Tone Mix). Sweetens the tone with no long decay tail. Use Space Send in Atmosphere for a real tail.

Track (T1–T8) — One of eight parts, each with its own recording, sound, and mixer channel. Each track is automatically a synth, sample, or drum track based on what you record on it; clear its loop to switch types. Tapping a track with recorded content switches the performance screen to its instrument.

Transport — Playback — whether the loop is running and where you are in the timeline.

V

Voicing — The chord shape you play: triad (default), 7th, or sus2. Each stroke in Chords mode records its voicing separately.