How Sound Is Stored

Sound is vibration moving through air. Your ear feels fast pressure changes as pitch and loudness. A microphone turns those changes into an electrical signal.

Computers cannot store a smooth curve perfectly. They measure the signal at regular times and write down numbers. That is sampling.

Open the sound wave lab. Step through samples on a wave and see each dot store one height value.

Sample rate is how many measurements per second. CD quality uses forty-four thousand one hundred samples per second, written 44.1 kHz. Higher rates capture high pitches more accurately.

Bit depth says how finely each sample is stored. More bits mean smaller volume steps and less noise when you edit quietly.

Phone voice notes use lower rates because speech needs less bandwidth than music with cymbals.

Speakers read the number list in order and push air accordingly. Your brain hears continuous sound even though the file was dots.

If samples are too sparse, high notes sound dull. If storage is too coarse, you hear hiss when volume is low.

Next you will learn why files shrink with compression without deleting the whole song or photo.