Tablature

Multitrack tablature editor inspired by Guitar Pro, with HD playback directly in the browser via Web Audio + Service Worker cache. Write scores for guitar, bass, keys and drums, save as .rostab in Finder, and export to MIDI.

Overview

Tablature combines three things that usually require separate paid software:

• Visual editor — grid with strings × measures × subdivisions, just like traditional editors.
• Professional playback — MusyngKite soundfonts cached by the Service Worker (plays offline after the first load).
• Practice companion — backing tracks catalog, chord chips with fingering diagrams, "Study Scales" mode.

No install, no paid login, no losing files between devices — .rostab files save to your Finder via Firebase Storage and follow you in any browser.

Multi-tracks

Each project can hold as many tracks as you need:

Type	Strings/Pads	Notes
Guitar	6 strings tuned E-A-D-G-B-E	Standard / Drop D / Open G / DADGAD selectable
Bass	4 or 5 strings	E-A-D-G or B-E-A-D-G
Keys (melodic)	single melody line	For licks/leads
Keys (SATB)	grand-staff with voicing split	LH (bass + tenor) + RH (alto + soprano) — appropriate for choirs or piano arrangements
Drums	pad grid	Kick, snare, hihat, crash, ride, toms, claps, etc.

The side Mixer controls per track: mute, solo, volume, voice (instrument), kit (for drums), custom name, and removal.

HD audio

The audio engine plays by default at high quality using MusyngKite soundfonts (gleitz CDN) for melodic instruments and Tonejs/audio (jsdelivr) for drum samples.

Available voices (melodic)

• Guitar — clean, acoustic steel-string, nylon (classical), jazz, distorted
• Bass — fingered, picked, slap
• Keys — acoustic piano, electric piano, organ, lead, sine, vibraphone, marimba
• Strings — cello, violin, strings ensemble
• Wind — flute, saxophone
• Brass — brass section

Drum kits

• Acoustic — acoustic kick, snare, hihat (closed/open), crash, ride, toms (low/mid/high), claps
• Electronic (4OP-FM) — synthetic kit TR-808 / TR-909 style
• Latin — conga, cowbell, shaker (some pads use procedural synthesis)

Offline cache

On the first playback, the Service Worker downloads the required samples and caches them for 1 year, up to 200 entries (LRU eviction). After that, playback works without internet — RoqueOS is PWA-first.

Backing tracks

The "Backing Tracks" button opens a catalog with 30+ presets, categorized:

• 🎸 Rock — Am 4-bar, G 8-bar, E power chords, Em ballad, Stoner Rock Dm
• 🎺 Blues — A 12-bar, E 12-bar, Slow G, Minor Am
• 🎷 Jazz — Cmaj7 turnaround, Am7 II-V-I, Bebop bridge D, Modal Em7
• 🥁 Funk — Em groove, D Dorian, Am shuffle, Disco Am
• 🌴 Bossa — Cmaj7, Dm "Quiet Night", Am "Garota de Ipanema"-style
• 🎶 Pop — 4 chords in C, Axis G, 50s in C, Em ballad
• 💃 Latin — Samba C, Mambo C, Reggae Am, Flamenco Em
• 🎛️ Electronic — Hip Hop Cm, Trap Fm, House Am, Techno Em, DnB Am

Each preset loads the basic harmonic structure (chords, rhythm, suggested BPM) into your tab — you play over it. The companion "Study Scales" button surfaces the compatible scales for the preset.

Chord chips

Drop chord chips on top of measures via "Insert chord". Each chip opens the ChordDiagramModal showing:

• Visual fingering diagram (guitar neck with frets)
• Notes that make up the chord
• Voicing specifically used in the diagram
• A "Play" button that quick-previews the chord

Chips auto-adjust when you change duration or measure position.

Per-measure time signature

Each measure can carry its own time signature. Supported:

• Simple — 2/4, 3/4, 4/4
• Compound — 6/8, 9/8, 12/8
• Irregular — 5/4, 5/8, 7/8

Changing recalculates stepsPerMeasure automatically. If the new time signature truncates the measure (e.g. 4/4 → 3/4), the app offers to drop notes outside the range.

Persistence: .rostab in Finder

Files save as JSON .rostab in your Finder (Firebase Storage). Anything in Finder is available from any logged-in device.

• Double-click a .rostab in Finder to open it directly in Tablature.
• Custom icon audiotrack in Finder differentiates .rostab from other audio files.
• "Open with..." in the context menu explicitly offers "Tablature".

MIDI export

The "Download" button exports as .mid (MIDI file format) — compatible with Reaper, Cubase, Logic, MuseScore, GarageBand, any DAW.

Mobile UX

Tablature is designed to play on any screen:

• Side drawer for the mixer on mobile.
• Centered transport bar with 3 large buttons — rewind (sky-blue), play (purple), BPM stepper (orange).
• Fret keypad 0-24 in a horizontal scrolling row (backspace pinned to the right).
• Smart backspace — after typing, backspace moves cursor back + clears, mimicking a text editor.

Keyboard shortcuts

Key	Action
0-9	Type fret (2 digits = fret 10-24)
S / P / G	Toggle sustain, palm-mute, ghost
Backspace	Step back cursor + clear cell (smart backspace)
Tab / Shift+Tab	Next / previous measure
Space	Play / Stop
← → ↑ ↓	Navigate cell by cell

External MIDI output

Beyond the internal synth, you can route output to a physical MIDI device via the Web MIDI API:

1. Plug in your MIDI controller / interface.
2. Go to Mixer → MIDI Output.
3. Pick the device — all tracks now play through MIDI hardware.

Useful for integrating with hardware sound modules, hardware samplers, or sending to another DAW.

See also

• Music Player — for playing audio files saved in Finder (mp3, flac, wav).
• Finder — where your .rostab files live.
• Getting started — Low-End Mode auto-disables heavy effects on weak devices without affecting audio playback.