Signal processing
Generate signals, mix them together, add noise, and apply filters. See the time domain waveform and frequency domain spectrum side by side. Press play to hear what mathematics sounds like.
Signals and spectra
Every periodic signal can be decomposed into a sum of sine waves at different frequencies. The Fast Fourier Transform (FFT) computes this decomposition efficiently, revealing the frequency content hidden in a waveform. A pure sine wave produces a single spike in the spectrum; a square wave reveals the odd harmonics (1, 3, 5, 7...) that compose it.
Filtering
A low-pass filter removes frequencies above a cutoff, smoothing the signal. A high-pass filter removes frequencies below the cutoff, isolating rapid oscillations. A band-pass filter keeps only a narrow range of frequencies. In the frequency domain, filtering is multiplication — zeroing out the unwanted frequencies.
Additive synthesis
Mixing signals is simply adding their waveforms point by point. This is the basis of additive synthesis in audio: any sound can be built from sine waves. The chord preset demonstrates this — three pure tones at harmonic intervals.