Additive-Synthesis

BKS Harmonic is a music-theory-aware additive synthesizer — a sound is a stack of partials you reshape directly. The whole layout at a glance, and how the modules fit together.

The heart of BKS Harmonic — the glowing pad where you set how many harmonics are open (vertical) and how the series folds across octaves (horizontal). Plus solo mode for hearing each partial.

The three controls that make BKS Harmonic what it is. Fold pulls the harmonic series down through the octaves, Gin lets the sub-fundamental layers sound, and Tonic keeps them anchored to the root.

The scope is how you watch a sound being built. Oscilloscope, FFT, vibrating string, harmony, and a per-partial info readout — and why each view earns its place.

Four controls for finer spectral shaping — Re-excite, Converge, Phase, and Clamp. Where the matrix sets the broad strokes, these reach in and rearrange the partials themselves.

Sculpt is hands-on spectral drawing: per-partial level bars, a Morph slider that sweeps between classic waveshapes, and a Blend that crossfades the whole sound into resonant noise.

The overtone scan sweeps focus across the partials you've built — not adding new notes, but bringing the components already in the sound in and out of focus over time.

A second envelope that shapes only a chosen group of partials — so part of the spectrum can swell in, click, or fade away on its own timeline, independent of the note's main volume.

Building sound from individual harmonics. The Fourier transform in plain language, drawbar organs, the Synclavier, and why additive gives you total spectral control at the cost of complexity.

The music-theory move: boost the partials whose pitch matches the chord or scale you're playing, so the timbre reinforces the harmony. Play in key and the sound follows.

Where the synth's music-theory roots show: choose pure just intonation or equal temperament, stretch the partials into piano-like inharmonicity, and thicken with unison.

A guide to BKS Harmonic — the music-theory-aware harmonic synthesizer. Additive synthesis built around the harmonic series, the partials matrix, gin and tonic, the overtone scan, and the sculpt and resonant engines.

A second sound source under the partial engine — noise, a classic oscillator, or a detuned double of the whole matrix. With its own tuning and filter, it adds body, grit, or width.

The familiar cutoff-and-resonance filter, plus three twists tied to the rest of the synth — Scan tracking, keyboard follow, and a Pluck transient.

The main amplitude envelope — standard ADSR plus a Fade for piano-style decay and VCA/VCF amounts that decide how much the envelope shapes the volume and the filter.

The system that drives everything else. A second LFO and envelope, performance sources like velocity and the mod wheel, and a mod matrix that routes any of them to almost any control.

The final stage — transpose, stereo width, drive, level, pan, and velocity sensitivity, plus mono-sum and auto-gain for keeping patches consistent.

The built-in finishing chain — EQ, delay, and reverb — color-coded so they read apart at a glance. Enough to make a patch sit in a mix without leaving the synth.

The everyday housekeeping — browsing and sharing patches, the PANIC and RAND buttons, and the Settings panel for glide, polyphony, pitch bend, and getting help.

A sawtooth wave, a mod wheel, and the space between equal and just tuning. The harmonic synthesizer crossfades between temperaments so intervals drift like a real string player.

What started as a way to visualize the harmonic series turned into a harmony-aware additive synthesizer. It folds overtones across octaves, tracks scales from partials, and does things conventional synths can't. Free on our website.