Choose a guide by what you are trying to do
I want to understand 303 sequencing
Start with the 303 Pattern Programming Guide. It explains what each step can contain, why rests matter, how ties differ from slides, how octave changes affect phrasing, and why accent works best as contrast rather than decoration.
I want concrete patterns to study
Use the Annotated 303 Pattern Examples. The examples are original study patterns written for this site. Each one isolates a different problem: sparse rhythm, octave call-and-response, slide tension, offbeat phrasing and single-pitch groove.
I want to connect a machine
Read the MIDI & Hardware Workflow Guide. It treats browser permission, output selection, device profile, channel matching and playback mode as separate checkpoints so you can diagnose silence without changing unrelated settings.
I need evidence from a real TD-3 transfer
Use the TD-3 USB Pattern Transfer Lab. It records the tested difference between live notes and memory writing, the exact safety sequence, a controlled test pattern and a failure matrix.
I want the musical context
The Acid House Guide explains how a short bass phrase becomes expressive through filter movement, resonance, accent, slide and its relationship with the rhythm section.
Why this library exists beside an interactive tool
An interface can show a control but it cannot explain when that control is useful. A slide button does not tell you whether the destination note creates tension. A MIDI channel selector does not tell you why a connected device can remain silent. A random button does not teach the difference between a structured starting point and a finished musical idea.
The library fills that gap. The goal is to make the site useful even when you are not actively pressing play: you can read a workflow, understand why it works, then return to the grid and test the idea yourself.
What is documented as fact, and what is a recommendation
The guides separate interface behavior from musical advice. Interface behavior describes what 303box currently exposes: a sixteen-step pattern, note/gate decisions, accent and slide, browser playback, supported MIDI profiles and external output routing. Recommendations describe practical ways to use those tools, such as starting with fewer active notes or checking the MIDI receive channel before changing transport settings.
Hardware configuration can differ by firmware, cable path and user settings. When a statement depends on the device, the guide treats the manufacturer documentation and the device's own settings as the final authority. 303box is an independent project and compatibility references are not claims of manufacturer endorsement.
A repeatable learning path
- Build rhythm first. Create a sixteen-step gate pattern with real rests before choosing lots of notes.
- Limit pitch vocabulary. Use a root plus a few related notes so expression has room to matter.
- Add contrast. Place accent, octave and slide only where they change the phrase.
- Audition in the browser. Make sure the line works before solving hardware routing.
- Connect one output. Confirm the browser sees the intended MIDI device.
- Match the receive channel. A correct output with the wrong channel is still silence.
- Choose playback mode deliberately. Use browser-only, browser + MIDI or MIDI-only according to the session.
- Transfer the idea, then perform it. Treat the browser as the notebook and the instrument as the performance surface.
Common terms used across the site
Gate describes whether a step produces or continues a note. Accent marks a stronger event. Slide keeps continuity while pitch moves toward another note. Octave U/D moves a pitch up or down one octave. Output is the MIDI destination exposed by the browser. Profile is 303box's device-oriented routing behavior. Playback mode decides whether sound stays in the browser, goes to MIDI, or both.
What makes a useful 303box article
A page should help a reader make a decision they could not make from a button label alone. That means examples need explanation, troubleshooting needs checkpoints, and musical advice needs a reason. The site avoids publishing near-duplicate pages that simply repeat the same definitions with different keywords.
When the app changes, the relevant guide should be reviewed. The About page describes the project's editorial standards, independence and limitations in more detail.
Continue from here
If you have never programmed a 303-style line before, read the pattern guide first. If you already know the vocabulary, jump directly to the examples and enter one pattern by hand. If your current problem is hardware, keep the sequencer stopped and follow the MIDI guide from permission to output to channel in that order.