Spectral Harmony, Hands-On
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What is spectral harmony?
It's the compositional tradition (Grisey, Murail, and others) of building harmony directly from the acoustic overtone series instead of triads and traditional tonal function. SpectralLab lets you see, hear, and play with that overtone series directly.
What's the difference between True Harmonic and Equal Temperament?
True Harmonic sounds each partial at its exact acoustic frequency (n × the fundamental). Equal Temperament rounds that same partial to the nearest 12-tone-equal-temperament semitone — the tuning a piano uses. Toggling between them makes audible exactly how far real overtones drift from familiar Western tuning.
How do I analyze a real sound?
Open the Analyze tab, record with the microphone or import an audio file (or try one of the built-in synthesized demo sounds), and SpectralLab detects its fundamental frequency and the amplitude of each of its harmonics via on-device FFT analysis.
What are the drawbars in Chord Builder?
Each drawbar controls one harmonic partial's volume, Hammond-organ style. Stack them to build a "spectral chord," play it through the built-in synth, or — once you've analyzed a real recording — through a 16-band EQ that shapes your own audio's actual harmonics.
What does the LFO ("breathing") toggle do?
Tap a drawbar's number to give that one partial its own independent cyclical volume modulation — its own rate and depth — so a static chord can breathe and shift on its own.
What's the Sequencer for?
It chains multiple spectral chords (each with its own fundamental, drawbar levels, and sound source) into a step progression, so you can build a chord change over time instead of a single static sound.
Can I export what I build?
Yes — both the Chord Builder and Sequencer can export Standard MIDI Files, with pitch bend encoding each partial's true (non-tempered) tuning so it isn't lost on export.
SpectralLab does not collect any personal data, does not require an account, and does not connect to the internet. Microphone access is used only to record audio locally for on-device analysis — nothing is ever transmitted anywhere. All processing, storage, and playback happens entirely on your device.