Sinusoid Visualizer
Amplitude · Frequency · Waveform · Spectrogram
Explore how a pure sinusoidal tone changes with its two fundamental parameters: frequency (pitch) and amplitude (loudness). The human auditory system perceives frequencies between roughly 20 Hz and 20 000 Hz (20 kHz). Use the frequency slider to go all the way up to 28 kHz and observe that above 20 kHz the tone enters the ultrasonic range — the oscillator still runs, yet no sound is heard.
880 Hz
✓ Audible — 20 Hz – 20 kHz
50 %
Piano Keyboard — click a key to set the frequency
Waveform — Time Domain
Spectrogram — Frequency over Time
The dashed yellow line marks the 20 kHz boundary. Energy above it is ultrasonic and inaudible to humans. The spectrogram is limited to the Nyquist frequency of your audio device (typically 22–24 kHz).