Jam-a-Lot User Manual
Welcome to Jam-a-Lot, your browser-based jazz practice companion. Jam-a-Lot plays synthesized acoustic drums, double bass, and electric piano accompaniment over a jazz standard's chord changes while displaying a clean lead-sheet style chart.
1. Playback & Live Performance Controls
Transport Controls
Located at the top of the interface:
- Play / Stop / Pause: Controls the playback state.
- Count-in: Select between 1 or 2 bars of count-in.
- Metronome: Toggle a metronome click on or off.
- User Menu: Sign in via Google OAuth or Email/Password, manage cloud library sync, give feedback via the Feedback modal, and view active user preferences.
User Account & Preferences Menu
- Join Beta Program / Account Button: Labeled "Join Beta Program" (with sparkles icon) when signed out. Toggles user profile menu when signed in.
- Guest Mode Notice Banner: Persistent notification explaining Guest Mode (3 demo tunes: Blues in F, Oleo, & Mr. P.C.).
- Cloud Library Sync: Back up custom charts and preferences to your personal Supabase account across browsers and devices.
- Give Feedback: Submit bug reports, feature requests, sound quality feedback, or general comments with interactive star ratings.
Bandstand Stage
The animated band graphic above transport controls allows screen theater mode expansion. Hotspot labels (bassist, drummer, comping style, room) cycle settings on click.
Performance Panel
Located directly below the transport. Split into four core tabs:
| Tab | What's in it |
|---|---|
| Structure | Chorus plan — head choruses, soloists count, bass/piano features, trading, last head, energy ramps. |
| Rhythm | Feel pickers for First chorus, Solo choruses, Out-head, and per-section style overrides. |
| Intro & Ending | Intro/ending style pickers including Tonic Splash (land on tonic with single cymbal splash). |
| Arrangements | Save and recall complete performance plans under custom names. |
Solo Rhythm — Following the Form or Opening Up
Under solos, choose whether the rhythm section follows the written form or switches to a single style (e.g. Swing) after N choruses:
- Follow written form: Every solo chorus plays section rhythms as written.
- Switch to [Feel] after N choruses: Plays written form for N choruses, then switches to selected feel for remaining solo choruses.
2. Chord Chart Views
Jam-a-Lot offers multiple layout modes to suit your practice setup:
- Standard Grid: Classic 4-column layout mapping bars evenly.
- Compact View: Authentic real-book lead sheet notation replacing grid lines with traditional bar markings.
- Repeat View: Collapses repeating sections using standard musical repeat brackets (
|:and:|). First and second ending brackets light up dynamically as playback enters each pass. - Vintage View: Amber monospace layout displaying full form without repeat folding.
Section Color-Coding
- Section A: Sky-blue
- Section B: Mint-green
- Section C: Soft-violet
- Section D: Warm-amber
- Section E+: Dusty-rose
3. Instrument Mixer & Quick Controls
Out of the box, all three instruments play at a calibrated level (expressed in decibels dB).unity 0.0 dB represents the calibrated baseline.
Stage Plot & Stereo Panning
| Voice | Position | Description |
|---|---|---|
| Piano | L35 | Busiest sustained voice gets left side |
| Bass | R35 | Right of centre, clear of kick drum |
| Kick / Snare | C / L3 | Anchor of the beat holds middle |
| Hi-hat / Ride | L32 / R30 | Spread across drummer's seat perspective |
| Toms | R18 | Sweeping across as pitch descends |
| Crash / Splash | L42 / R38 | Wide accents for clear event separation |
Importing Custom Piano Samples (SFZ)
- In Piano card, click Import samples….
- Select both your
.sfzfile and referenced.wavfiles together. - Audition C4 and click Import Kit. Saved to browser IndexedDB automatically.
4. Rhythm Styles & Bossa Nova Fine-Tuning
Jam-a-Lot separates feel, rhythm style, and mixer sound. Accompaniment families include Swing, Ballad, Gypsy Jazz, Bossa Nova, Latin, Waltz, Soul-Jazz, Funk, Blues Shuffle, R&B / Neo-Soul, Rock, and EDM.
5. Drummer Avatars & Human Feel
Select preset drummer profiles under Settings → Feel & Variation:
- Philly Joe: Swing-forward, traditional timing, and natural feel.
- Elvin: Loose timing, heavy syncopations, high comping intensity.
- Tony: Driving feel, ride-focused, razor-sharp timing.
- Max: Balanced swing, structured snare fills, melodic flow.
Bassist Avatars
Includes Standard Walk, Jaco, Eddie Gomez, Ray, Paul, and Ron profiles.
7. Creating & Editing Songs
Text Mode Editor Shorthand
The Chord Editor opens in text mode by default. Universal lead-sheet syntax:
| Symbol / Syntax | Description | Example |
|---|---|---|
| | Single barline | | Cmaj7 | Dm7 G7 | |
|| | Double section barline | | Cmaj7 | G7 || |
|: ... :| | Repeat section | |: Cmaj7 | Am7 | Dm7 | G7 :| |
: | xN | Repeat N times | |: C | G7 :| x3 |
[Section] | Section label | [A] or [Bridge] |
/ or % | Hold previous bar chord | | Cmaj7 | / | |
N.C. | No Chord (silent bar) | | Cmaj7 | N.C. | |
8. The Listening Band (Microphone Input)
Open Listening in the header row to arm the microphone. The band listens in real time and adapts to your performance.
- Follows Energy: Adjusts band dynamics bar by bar based on your input level.
- Phrase Answering: Fills gaps when you pause your solo line.
- Figure Catching: Locks onto repeated 1-bar or 2-bar rhythmic figures played into the mic.
- FFT Leakage Subtraction: Subtracts the band's audio from mic input bin-by-bin for clean speaker operation.
9. Screen Layout & Full Screen
Supports full-screen performance view (Esc to exit), dynamic chord resizing, and auto-scrolling to keep active bars in view.
10. Background Audio Support
Jam-a-Lot keeps playing smoothly when you lock your screen or switch browser tabs, using Web Audio Web Worker timers for precision lookahead scheduling.