Drum generator

Getting started

When you open CedarGrooveNET, you see an empty 16-step grid with the prompt "Draw a pattern or drop a MIDI file". The grid is your primary workspace — each row represents a drum instrument and each column is a 16th-note step. You have three ways to get a starting pattern:

• Draw it — click cells directly to build a beat from scratch.
• Drop a MIDI file — existing MIDI is parsed, quantised, and mapped to the 11 drum classes.
• Got audio? — the drum transcriber turns a WAV/MP3/FLAC/AIFF drum loop into MIDI first (DrumTranscriber v2), and its Generate from this opens these same controls under the transcription. Dropping audio here points you there.

Drawing patterns

• Click any cell in the grid to toggle a drum hit on or off. Active cells light up in blue (input) or pink (generated).
• Each row is labeled with its drum instrument name (Kick, Snare, CHH, OHH, LTom, MTom, HTom, Crash, Ride, Clap, Rim).
• Each column represents one 16th-note step. Four columns make up one beat, and 16 columns make up one bar.
• Click and drag across multiple cells to draw or erase several hits at once.
• Hold Alt and drag vertically on an active cell to adjust its velocity. The cell's brightness changes to reflect the velocity value.

Grid row management

The grid starts with the most commonly used drums visible. You can customize which rows are shown and how they're arranged:

• Add rows: Click the + button at the bottom of the grid to add additional drum instruments that aren't currently visible (e.g., toms, crash, ride).
• Reorder rows: Click and drag any drum label (Kick, Snare, etc.) up or down to rearrange the row order to your preference. A floating preview shows the row being moved.
• Mute / Solo: Each row has small M (mute) and S (solo) buttons on the left side. Mute silences a drum during preview playback; Solo isolates it so only that drum plays. Muted rows appear dimmed in the grid.
• Right-click context menu: Right-click any drum label to open a context menu with options to regenerate just that single row (keeping all others unchanged) or clear it entirely.
• Row locking: the lock at the left of the row name protects it during generation — locked rows keep their pattern while all other rows are regenerated. Useful when you have a perfect kick pattern and want to regenerate only the snare and hi-hats.

Loading MIDI files

This page takes MIDI (.mid, .midi). Audio (.wav, .wave, .mp3, .aif, .aiff, .flac) belongs on the drum transcriber page, which turns a loop into MIDI and offers these controls under the result.

• Drag and drop a file anywhere on the page, or click the drop zone below the grid to open a file picker.
• MIDI files are parsed server-side, quantised to a 16th-note grid, and mapped to the 11 standard drum classes using General MIDI note mappings. BPM comes from the MIDI tempo track.

Generating continuations

• Once you have an input pattern (drawn, loaded from MIDI, or transcribed from audio), click Generate to run the LSTM generator.
• The model analyzes your input and generates a continuation that respects the rhythmic feel, dynamics, and instrument balance of your original pattern.
• Generated steps appear in a different color (pink/coral) next to your input steps (blue/cyan), making it easy to distinguish what you wrote from what the AI created.
• Use the bars stepper to set how many bars to generate: 1, 2, 4, 8 or 16. Longer generations give the model more room to develop ideas, while shorter ones keep things tight.

Parameters (knobs)

Four knobs in the toolbar shape the generation; the Volume knob in the header sets the preview level:

• Temperature (0.5 - 1.2): Controls the randomness of the generation. Lower values produce more predictable patterns that stay close to the training data. Higher values introduce more creativity and variation. The default of 0.85 provides a good balance between coherence and surprise.
• Density (0.0 - 1.0): Scales the probability of hits in the generated pattern. Lower values produce sparser patterns with more space. A value of 1.0 gives you the full density output from the model. Use lower density for ambient or minimal styles, higher for busy breakbeats.
• Velocity (0.1 - 2.0): Scales the velocity (loudness) of generated hits. Values above 1.0 boost velocities for a harder, more aggressive feel. Values below 1.0 soften the output for more delicate dynamics.
• Humanize (0.0 - 1.0): Adds subtle timing and velocity variation to the generated pattern, making it sound more natural and less mechanical. Higher values introduce more variation. Even small amounts (0.1 - 0.3) can make a noticeable difference in feel.
• Volume (-60 to +6 dB): Master output volume for the Web Audio preview engine. This controls only the preview playback level, not the generated pattern data.

Groove templates

Groove templates apply timing offsets to the playback, giving your pattern swing, shuffle, or genre-specific timing feels. Select a template from the Groove dropdown and use the Amount knob to control how strongly the groove is applied (0.00 to 1.00).

Available groove templates fall into several categories:

• Straight — No groove applied. Perfectly quantised 16th-note playback.
• MPC Swing — Five levels of swing inspired by the Akai MPC's iconic timing feel, from subtle 54% to heavy 71%.
• Roland TR-808 Shuffle — The classic shuffle feel from the legendary drum machine.
• Logic Funk — A funky groove template with characteristic off-beat emphasis.
• DnB Grooves — Five drum-and-bass-specific timing templates:
  • Liquid — Smooth, flowing timing for liquid DnB
  • Neurofunk — Precise, tight timing for neurofunk
  • Jungle — Loose, breakbeat-inspired timing
  • Half-time — Half-time DnB groove feel
  • Roller — Rolling, driving timing for roller-style DnB

Reference Genre & Style Influence

The style system uses influence, not presets. Unlike traditional presets that rigidly dictate a pattern, style influences are soft constraints that guide the model's generation toward a particular rhythmic feel. The model still generates original patterns — the influence just steers the probabilities, making certain kick placements, snare positions, and rhythmic structures more likely without forcing them. This means every generation is unique, even with the same style selected.

The Genre menu selects a reference genre to constrain the generation process. When a genre is selected, the model's output is modulated by genre-specific kick and snare templates hand-authored for each genre. All nine genres — Drum & Bass, House, Rock, Hip Hop, Trap, Techno, Reggaeton, Afrobeat and Jazz — are implemented; each comes with 10 sub-style presets that appear in the Style menu once the parent genre is selected.

The nine reference genres and their ninety sub-styles are listed on the genres page.

Preview playback

• Click "Preview" to hear your pattern played back through the built-in Web Audio drum synthesiser. The synthesiser generates 11 distinct drum voices entirely in the browser — no samples or external audio files needed.
• The BPM control sets the playback tempo. Click the number to type an exact value, use the +/- buttons to adjust (hold Shift for steps of 10), or scroll the mouse wheel for fine adjustments.
• Press Space to toggle playback on and off.
• Click on the marker strip above the grid to seek the playhead to a specific position.

Exporting & MIDI file format

• Click Download MIDI to download your pattern as a standard .mid file.
• The exported MIDI includes both your input steps and the generated continuation steps.
• If a groove template is active, its timing offsets are baked into the exported MIDI for authentic feel.
• Files are named sequentially: {original_name}_CedarGrooveNET_001.mid, incrementing with each export. Loading a new MIDI file resets the counter.

MIDI encoding details

Exported MIDI files follow the General MIDI (GM) Drum Map standard. All drum notes are output on MIDI Channel 10 (the standard GM percussion channel), so they will be automatically routed to drum instruments in any DAW or GM-compatible synthesiser.

Each of the 11 drum classes maps to a standard GM drum note number:

The exported file is a Type 0 (single-track) Standard MIDI File with a tempo meta-event at the beginning matching your BPM setting. Note velocities are preserved from the grid (0-127 range), so dynamics you set via velocity editing carry through to the export. The file uses 480 ticks per quarter note for high timing resolution.

Other controls

• Undo / Redo: Use the arrow buttons in the controls bar, or press Cmd+Z to undo and Cmd+Shift+Z to redo. Every grid edit, generation, and parameter change is tracked in the undo history.
• Clear: Removes all patterns from the grid, giving you a blank slate.
• Fill: replaces the last generated bar with a drum fill (toms, crash, snare). It needs a generated pattern.
• Pattern Slots (A/B/C/D): Four pattern slots. Click an empty slot to save the current pattern into it, click a filled slot to recall it, and click the active slot again to update it with what is on the grid.
• Row controls: Right-click a drum label to open a context menu where you can regenerate or clear just that single row. Drag drum labels up and down to reorder rows to your preference.

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