Drum Synthesizer (WAV one-shots)

What it is for

The Drum Synthesizer builds a drum hit from scratch, without samples, and gives you a 16-bit 44.1 kHz mono WAV one-shot you can load into any sampler or DAW. It is the same renderer as the Drum Lab tab of the Tonegrid app, so a sound you design there and copy with Copy settings comes out sample-for-sample identical here.

A sound has three ingredients. The tone is an oscillator whose pitch sweeps from a start to an end frequency (the "thump" of a kick or the body of a tom). The noise passes through a low-pass, band-pass or high-pass filter (the rattle of a snare, the hiss of a hi-hat). The metal layer is six square waves at inharmonic ratios, the classic way to make a cymbal or hi-hat. Clap bursts, a short click, and tanh drive complete the set.

Worked example

Choose the preset Hand clap and leave the settings empty. The result reads "Hand clap: a 0.258 s clap one-shot, peak -1 dBFS, RMS -20.3 dBFS", with a spectral centroid of 2394 Hz. The waveform shows several short noise bursts followed by a longer tail. That is how a clap is synthesized: a few hands that do not hit at exactly the same time.

Now choose Deep kick and enter:

{"name": "Boom kick", "toneEnd": 38, "toneDecay": 0.9, "drive": 0.35}

The kick gets longer and dirtier: 0.905 s, RMS -9 dBFS and a spectral centroid of 62 Hz. Without the drive setting the same kick has an RMS of -12 dBFS, because drive raises the average level while the peak stays at -1 dBFS.

The third example starts from Open hi-hat and sets {"noiseHz": 5200, "noiseDecay": 0.6}. The spectrum lists its strongest lines at 3972.9, 3352.2 and 3532.1 Hz: the square-wave partials of the metal layer.

How to read the result

• Length is the time until the sound has decayed, with a short fade so the file ends at silence.
• Peak level is always -1 dBFS: every sound is normalised to the same peak, so you can compare presets fairly. RMS level tells you how loud it feels.
• Spectral centroid is the "centre of gravity" of the spectrum: low for kicks, high for hats.
• The Settings used table shows every value after your changes, ready to paste back into the tool or the app.

Tips and common mistakes

• The settings field is JSON: put names in double quotes and use a dot as the decimal separator.
• Values outside the allowed range are rejected with the setting's name, for example a toneEnd below 20 Hz.
• A short pitchDecay (0.02–0.05 s) gives a clicky, punchy kick; a long one (0.15 s and more) sounds like a laser or a tom fill.
• For snares, mix a tone of 180–220 Hz with band-pass noise around 2–4 kHz.

FAQ

Are these samples from a drum machine?

No. Every sound is calculated from its settings by a deterministic program, with seeded noise, so the same settings always give the same file.

Can I use the WAV files in my music?

Yes. You designed the sound, and the output contains no third-party material.

Can I make stereo files?

The one-shots are mono, which is the norm for drum samples; place them in the stereo field in your mixer.