Question 1

What is a spectrogram?

Accepted Answer

A spectrogram is a visual representation of the spectrum of frequencies in a sound as they vary over time. Time runs along the horizontal axis, frequency along the vertical axis, and color/brightness indicates the strength (amplitude) of each frequency at that moment. It reveals the harmonic structure of voices, instruments and noise.

Question 2

What is the difference between a spectrogram and a spectrum?

Accepted Answer

An FFT spectrum shows the frequency content at a single instant in time as a bar chart. A spectrogram stacks many consecutive spectrums left-to-right, producing a 2D heat-map that shows how the frequencies change. This tool shows both: the scrolling spectrogram on top and the live FFT spectrum below.

Question 3

Why are higher frequencies at the top?

Accepted Answer

Conventionally low frequencies (bass) are at the bottom and high frequencies (treble) at the top, mirroring a piano keyboard. The default linear scale shows equal spacing per Hertz; switching to the log scale gives more resolution in the lower octaves where most musical notes live.

Question 4

Is my audio sent to a server?

Accepted Answer

No. The microphone stream is analyzed entirely in your browser using the Web Audio API and Canvas. Nothing is recorded or uploaded.