Sound,
made visible.

What are you changing?

Frequency is the number of cycles per second, measured in hertz (Hz). A 500 Hz sine wave completes 500 cycles each second. In the lab, the carrier animation is slowed 1,000 times so you can see it move. Optional audio uses the displayed frequency.

Amplitude controls the signal’s strength. In a sound wave this relates to pressure variation, but perceived loudness also depends on frequency, your hearing and playback level. The lab’s amplitude percentage is a relative control, not a calibrated sound-pressure reading.

Harmonics are components at whole-number multiples of a fundamental frequency. The sixth harmonic rotates six times as quickly as the fundamental in the Fourier view. An octave is specifically a doubling of frequency, so harmonics are not all octaves.

An envelope changes amplitude over time: attack, decay, sustain and release. It shapes how a note begins, settles and ends.

Why does the plate look different?

The plate is a model of a vibrating surface responding to the shared signal. Its shape changes the available modes of vibration. Particles gather near nodal regions, where the surface moves less. These are often called Chladni patterns, part of the study of cymatics. The UCLA Chladni plate demonstration shows how different mounting and excitation change the patterns.

A frequency alone cannot specify a universal pattern. A real plate’s dimensions, material, thickness, mounting, damping and drive position all matter. This is an educational simulation, not a prediction of every physical plate at the displayed frequency.

The dot matrix and propagation views are visual interpretations of the same signal. They help you compare changes, rather than measuring an actual room or sound field.

Rhythm is a relationship.

The rhythm study divides one shared cycle into different numbers of evenly spaced beats. Three beats trace a triangle; four trace a square. In a 3 : 4 polyrhythm, the layers meet at the start of each cycle. A 2 : 4 pattern is a simpler subdivision of the same pulse.

The numbers describe beats in a shared cycle, not time signatures. Tempo uses quarter-note beats per minute and each cycle lasts four quarter notes. You can layer up to twelve rhythms, change their note velocity and listen to each separately.

Link the rhythm study to the wave views to use its short beat envelopes as an amplitude control. Pitch and harmonic balance stay as you set them. The rhythm percussion is a separate listening reference, while the wave views show the pulsed shared source.