beat lab / filter
SUBTRACTIVE SCULPTING

Carve the
spectrum
away.

The inverse of the Fourier Sculptor. Start with a rich harmonic source — all 32 partials present. Then draw a filter curve to carve away what you don't want. What remains is the sound.

The gold line is your filter. Drag it down to remove harmonics. Drag it up to let them through. Dim bars show the source. Bright bars show the result. The negative space between them is what you carved.

Choose your source waveform. Try presets that generate classic filter shapes — lowpass, bandpass, notch, comb. Then override with your own curve. Every subtractive timbre is a mask you draw.

THE ARCHITECTURE
SUBTRACTIVE SYNTHESIS

The sculptor adds harmonics from nothing. The filter starts from everything and removes. Same Fourier math, opposite direction. The source provides all 32 partials. Your filter curve multiplies each partial's amplitude. A gain of 0 silences it. A gain of 1 passes it untouched. Everything between is gradation.

DUAL RECONCILIATION V5

Same dual-transducer architecture. SharedArrayBuffer carries 32 filter gains from main thread to AudioWorklet. The worklet multiplies source amplitudes by filter gains, then performs additive synthesis. Canvas reads the smoothed output back. One state (the filter curve), two renderers (audio + visual). The negative space is what makes it subtractive.

THREE-LAYER VISUALIZATION

Bottom layer: dim source bars showing full harmonic content. Middle: the gold filter curve — your control surface. Top: bright result bars showing what passes through. The gap between source and result is the carved-away material. You see the subtraction happening.

SCULPTOR + FILTER = COMPLETE

Additive and subtractive — the two fundamental approaches to synthesis. The sculptor is construction: building timbre from silence. The filter is destruction: carving timbre from noise. Together they cover the full creative space. Both use the same bridge. Both prove the same architecture. Different instruments, same substrate.

SIGNAL CHAIN
source harmonics
filter curve
SAB write
AudioWorklet multiply
additive synth
destination
Source
4 waveform modes
Filter
32-point gain curve
Transport
SAB / postMessage
Output
source * filter (per-bin)