From Repeating Voltage to Musical Pitch
An oscillator makes an electrical signal that rises and falls in a repeating pattern. How quickly that pattern repeats sets the note’s pitch: faster repetition produces a higher note, slower repetition a lower one. The signal itself is not yet sound in the air. A synthesizer sends it through audio circuitry and, ultimately, a speaker, whose cone moves back and forth to create pressure waves we hear.
Wave Shape Gives a Note Its Character
The repeating pattern also determines which frequencies accompany the note’s basic pitch. A smooth sine wave contains almost only that fundamental frequency, so it sounds relatively pure. Square and sawtooth waves contain additional harmonics—higher frequencies related to the fundamental—which give them a brighter, more complex edge. Triangle waves have harmonics too, but their strength falls off more quickly, making their tone softer than a square wave’s.
These shapes are starting materials, not fixed instrument sounds. A filter changes the balance of frequencies, often by reducing those above or below a chosen cutoff. Turning that cutoff while a note plays can make the sound shift from bright to muted, or create a moving, vocal-like sweep. The character of a synthesized note comes from both the waveform’s ingredients and how the instrument reshapes them.
