# Drum Synthesizer (WAV one-shots)

> Design a kick, snare, hi-hat, clap or tom from scratch and download it as a WAV one-shot. Synthesizes a drum sound without samples: a pitch-swept tone, filtered noise, metallic square-wave clusters, clap bursts, a click and saturation, each with its own decay. Start from one of eleven presets, change any setting with a small JSON object, and get a 16-bit mono WAV one-shot plus its waveform, spectrum and level. The same synthesizer as the Drum Lab in the Tonegrid app.

Part of usefulweb.app (https://usefulweb.app/). Part of [Tonegrid](https://tonegrid.usefulweb.app/) (ownerApp: tonegrid). Results are deterministic calculations from the inputs and the listed assumptions; the API returns exactly what the web page shows.

## Use it
- Human interface: https://tonegriddrumsynth.usefulweb.app/ (interactive tool at https://tonegriddrumsynth.usefulweb.app/tool)
- JSON API: POST https://tonegriddrumsynth.usefulweb.app/api/v1/calculate with a JSON object of inputs (schema: https://tonegriddrumsynth.usefulweb.app/api/v1/tool)
- OpenAPI: https://tonegriddrumsynth.usefulweb.app/openapi.json
- MCP (Streamable HTTP): https://tonegriddrumsynth.usefulweb.app/mcp - tool `tonegrid_drum_synth`

## Inputs
- preset (select): Start from preset
- settings (textarea): Change settings (JSON, optional) - Any of: toneStart, toneEnd (Hz), pitchDecay, toneDecay (s), wave (sine/triangle), toneLevel, noiseLevel, noiseDecay, noiseFilter (lowpass/bandpass/highpass), noiseHz, noiseQ, metalLevel, metalHz, bursts, burstSpacing, click, drive, level, seed, name, kind. Empty = the preset as it is. Tonegrid’s “Copy settings” gives a complete object.

## Method
- Tone: a sine or triangle oscillator whose frequency falls exponentially from the start to the end pitch within the pitch-decay time and then stays (the phase is the exact integral of the sweep, so there are no clicks).
- Noise: seeded white noise (same seed, same sound) through a low-, band- or high-pass biquad filter (RBJ cookbook). Metal: six square waves at fixed inharmonic ratios (1 : 1.34 : 1.68 : 2.21 : 2.66 : 3.15) above the metal frequency, through the same filter, for cymbal-like hats. Clap: the noise envelope restarts for every burst; early bursts die within two spacings, the last one uses the noise decay.
- Each part has an exponential decay that reaches −60 dB at its decay time, plus a 0.5 ms attack ramp; an optional click is a 3.2 kHz sine burst of under 1 ms. Drive applies tanh saturation. The sound ends with a 2 ms fade to silence and is normalised: the WAV file peaks at −1 dBFS (16-bit mono, 44.1 kHz).

## Limits
- These are simple synthesized drums, not recordings of real instruments or of any drum machine. You may use the sounds you make freely.