Drum Foundry

An analog-style drum synthesizer for designing one-shot drum samples in the browser and saving them as WAV files. It's a sound design palette, not a drum machine: pick a starting point, shape it, hear it, save it.

Nothing is uploaded; every sound is rendered in your browser.

How it works

Every hit is rendered sample by sample at the sample rate you choose, then quantized to the bit depth you choose, so what you hear is exactly what gets saved: an 8-bit, 22 kHz kick sounds 8-bit and 22 kHz in the preview too. The waveform and spectrum views show the rendered file.

A sound has three parts plus a master section:

• Tone layer: two oscillators (sine, triangle, saw, pulse).
  • OSC 1: tune (type a note name like A1 or a frequency), level, pulse width, PWM depth and rate, and Drift (analog-style random detune and start phase).
  • OSC 2: tuned as a ratio of OSC 1, with fine tune, level, its own PWM, hard sync to OSC 1, linear FM into OSC 1 (a fixed amount plus a decaying FM envelope for bark and knock), and ring mod.
  • Pitch envelope: amount in semitones (up or down), decay, and curve from linear to exponential, applied to OSC 1 and optionally OSC 2.
  • VCF: LP12, LP24, BP, HP12, HP24 or notch, with cutoff, resonance up to near self-oscillation, an envelope (in octaves, with its own decay), and pitch tracking so the filter can follow the pitch sweep.
  • VCA: attack, hold, decay and curve.
• Noise & metal layer:
  • Sources: noise (white, pink, brown, or digital, a short shift-register noise), a metal bank of six square-wave oscillators at inharmonic ratios (six-square cymbal set, a tighter set, harmonic, two-oscillator bell, glass) with tune and spread, and stereo width when saving stereo.
  • VCF: its own filter with a separate low cut.
  • VCA: attack, hold, decay and curve, plus bursts (count, gap, burst length) for claps and rattles.
• Click: a short noise or blip transient for attack.
• Phases: repeat the hit instead of playing it once, for rolls, flams, ratchets, bouncing balls, stutters and vinyl crackle. Choose what repeats (Click, Noise layer, Tone layer, in any combination); each phase retriggers that part's envelopes and sweeps.
  • Phases: how many hits, 1 to 64. Gap: time between the first two.
  • Spacing: each gap gets shorter (faster, like a bouncing ball) or longer (slower) by this factor; Even keeps them steady.
  • Scatter: blends from even spacing to random spacing; 100% scatters the hits like crackle.
  • Fade: level change per phase in dB, down for decays, up for crescendo rolls. Level ±: random level per hit.
  • Step: shifts each phase's pitch, click tone and noise filter by semitones, so repeats can climb or fall. Tone ±: a random shift per hit.
  • Chance: the odds each phase after the first plays. Lowering it thins the pattern without reshuffling it.
  • The graph shows the timeline: one stem per hit, at its level. New seed reshuffles scatter and randomness.
• LFO: sine, triangle, square, saw or sample-and-hold, up to audio rate, to pitch, either oscillator, FM depth, pulse width, either filter, the metal bank, or level.
• Mix & drive: layer levels, drive (warm, clip, or fold), master low cut and high cut.
• Lo-fi & length: bit crush and sample-rate reduction (for the sound, separate from the file format), auto length (trimmed where the sound falls 66 dB below its peak) or a fixed length, end fade, gain, and normalize.

Working with it

• Layout: the sound's name, Play, the waveform and the spectrum stay at the top. Below them, tabs hold one section at a time: Tone, Noise & metal, Click & phases, LFO & master, Output (format, saving, sending, the session recorder) and Kit. A lit dot on a tab means that section is in use in the current sound. The page remembers the last tab.

• Add to kit is next to the name.

• Categories: Kick, Snare, Clap, Closed hat, Open hat, Cymbal, Tom, Percussion, Click & FX, each with several starting points. Buzz roll, Flam clap, Vinyl crackle, Glitch ticks, Bouncing ball and Stutter noise show off Phases.

• Audition on change plays the sound after each edit. Play (or the space bar) plays it any time.

• Knobs: drag up or right to raise, Shift for fine, double-click to reset. Click the number to type a value. Arrow keys and the wheel work while a knob is focused.

• Vary nudges every setting by the Vary amount. Random picks a starting point in the category and varies it. New seed keeps the settings and rerolls the noise and drift.

• Undo / Redo (Ctrl+Z, Ctrl+Shift+Z) cover every change.

• MIDI in: press it once to connect; any note plays the sound, with velocity. Press it again to have notes play the sound at their pitch (C4 plays it as designed).

Saving

• Output: 22.05, 32, 44.1, 48, 88.2 or 96 kHz; 8, 16 or 24-bit PCM or 32-bit float; mono or stereo; dither on or off.
• Save WAV saves the current sound. Every WAV carries its full patch in a small extra chunk (ignored by other software), so Load patch or WAV brings any sound saved here back for editing. Save patch saves just the settings as JSON.
• Kit: collect sounds with Add to kit or Add 8 variations, rename them, edit and replace them, then Save kit for one .zip of numbered WAVs plus kit.json. Load kit reads that .zip (or the JSON) back in.
• The current sound, settings and kit are kept in your browser between visits.

Send to Discobot

Send to Discobot (the current sound) and Send kit to Discobot (up to 64 sounds) open Discobot in a new tab and hand it the WAVs. Discobot opens its Import Kit dialog with each sound on a suggested drum lane (kick, snare, clap, closed hat, open hat, low or high tom, cymbal). Percussion and FX sounds are offered as new rows. Change any lane there and press Import; nothing is added until you do. The line under the buttons says when Discobot has them.

• Discobot's receiving side is still to come. Until it arrives, the button waits 45 seconds, then offers to save the file instead. See DISCOBOT-SEND.md for the handshake and the request for Discobot.
• The sounds go at the format chosen under Output. A file that would be over 4 MB goes as 16-bit, so it fits in a Discobot project file.
• If the browser blocks the new tab, allow pop-ups for this page.
• Saved files are named by drum (kick-…, snare-…, closed-hat-…, open-hat-…, cymbal-…, low-tom, perc-…, fx-…). That means a saved kit also lands on the right lanes through Discobot's Import Kit by hand: unzip it and pick the WAVs.

Send to Logic Rhythm

Send to Logic Rhythm (Output tab, the current sound) and Send kit to Logic Rhythm (Kit tab) hand the sounds to Logic Rhythm in the same browser.

• If Logic Rhythm is open in another tab, the sounds go straight to it. Switch to that tab to finish.
• If it isn't open, the status line offers Open Logic Rhythm, and the sounds follow once it has loaded.
• Logic Rhythm shows a dialog with each sound and the track it would play on: kick, snare, clap, closed hat, open hat, tom, and rim for a cymbal or percussion sound. Change any of them, or leave a sound on its Samples tab only, then press Load. Each sound becomes one of its sample slots, stored like an upload, so it is still there next visit. Sending a sound with the same name again updates that slot.
• This uses the shared kit-link.js module (the KIT-LINK block in index.html), a BroadcastChannel between the apps on aaronvandorn.github.io. It works in the copy on GitHub Pages, not in a preview hosted somewhere else.

Session recorder

Uses the shared jam-clips.js module (the JAM-CLIPS block in index.html), like the other apps: the last 48 seconds of what you've auditioned can be saved as WAV plus a MIDI file of the hits (General MIDI drum notes on channel 10), and Tape Loop Deck can capture from it.