Roundel

A practice tool for chord progressions, laid out as a transit map of the twelve keys — see how they move, hear them, and drill them until they are automatic everywhere.

The twelve keys are stations on a network. Each curriculum step is a line across it; a day's workout is a departure that calls at the keys you have opened. That map is how you navigate and how the lessons are built. The circle-of-fifths wheel is still here — it is the terrain the network is drawn on — and it is where you explore chords, neighbours and voice leading.

A progression is the real unit of harmony, not the chords in isolation: a ii–V–I means something as a single shape, not three symbols to memorise separately. Roundel puts that shape in front of you — on the wheel and across the map — while the rest of it makes sure you can also hear it, recognise it on your own instrument, and find it again next week.

The playing curriculum follows one loop, worked from every direction: take a progression, hear it, drill it across all twelve keys, and apply it — recognising it as you play, or playing along with a generated rhythm section.

SEE → HEAR → DRILL → APPLY

No staff notation, anywhere, ever. Not as an option, a toggle or an advanced panel. Music is keyboard diagrams, the wheel itself, chord symbols, scale-degree numbers, Roman numerals, intervals and colour. If you read chord charts fluently and staves not at all, nothing here will ask you to.

Free software, AGPL licensed. Run it on your laptop, deploy it wherever you like, change whatever you want. It is your own instance — no telemetry, and no server anyone else controls. Invite-only accounts let a small trusted group keep separate progress today; public registration and the paid hosted service remain planned in ROADMAP.md.

What it does

• Play — connect a MIDI keyboard and it names what you play as you play it, with the reasoning, on a harmonic wheel that shows why.
• Today — a workout of up to six tasks, composed fresh each morning and finished by meeting its goals rather than by running a clock down. Pick any key, any step or any progression to build it around; spaced repetition schedules the review and a twelve-key ladder suggests where to go next, and neither ever locks anything.
• Play along — a rhythm section generated from a chord chart. Walking bass, drums, optional comping, any key, any tempo, loop any bars. Blues, rhythm changes, cycles and public-domain standards, plus anything you type in.
• Explore — the wheel, chord neighbours, voice leading, with the notes under your hands lighting up as you play them.
• Recipes — theory you play rather than read. A chord's recipe is its formula: the intervals above its root, counted in half steps. A line of short stops goes from half and whole steps through thirds and the fifth to triads and seventh chords, each briefed in standard terms with the recipe drawn on C before you build it on the keyboard; and a branch line goes up in fifths until it comes back to C, then round the circle from memory both ways. Every answer is a note played. It keeps its own record and leaves the courses and the daily workout untouched.
• Profile — what has actually happened: hours played, chords judged, badges won, and the twelve keys as swatches so the ones you never play are visible at a glance. Every number traces to a row; none is an estimate, and there is no daily streak.

Signing in for the first time opens a short tour that sets the instrument up before it explains anything, and hands you the sustain pedal as the way through the rest of it. No MIDI keyboard? Everything works with the on-screen one, and the tour takes that route instead.

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Before you start: browser support

Connecting a MIDI instrument needs Chrome, Edge or Firefox on a desktop.

Web MIDI does not exist in Safari — on iOS, iPadOS or macOS — and every iOS browser is forced onto WebKit, so an iPad cannot drive the parts of this app that listen to a keyboard. See DECISIONS.md for the detail.

Everything else works everywhere, including on a tablet: the wheel, the play-along charts, the on-screen keyboard.

Web MIDI also requires a secure context. localhost counts; a deployed http:// origin does not, and will disable MIDI with no error message. Serve over HTTPS.

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Stack

Layer	Choice
App	SvelteKit 2 · Svelte 5 (runes) · TypeScript · Tailwind 4
Build	Vite 8 · @vite-pwa/sveltekit
Data	Postgres 15+ · Drizzle ORM · node-postgres
Audio	Tone.js — ear drills and backing tracks only
MIDI	Web MIDI API
Deploy	adapter-auto — Vercel, Netlify, Cloudflare, or Node
Tests	Vitest

Your instrument makes its own sound, so the app never synthesises a piano voice for what you play. It only generates audio for ear drills, backing tracks and the metronome — which is why there are no sampled instruments to vendor and the whole thing is a few hundred kilobytes.

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Running it locally

You need Node 22+ and a Postgres 15+. Docker gives you the second one.

git clone https://github.com/bparticle/roundel.git
cd roundel
npm install
cp .env.example .env    # the defaults already match docker-compose
npm run db:up           # start Postgres in Docker
npm run db:migrate      # apply the schema
npm run db:seed         # skills and chord charts
npm run account:create -- owner "Your name" "[email protected]"
npm run dev

以上为 README 的开头部分。其余内容请阅读原文。 查看完整 README ↗