What even is a vinyl record
A vinyl record stores music as one long wiggly groove.
A record is a flat plastic disc about 30 cm across. One thin cut line, called the groove, spirals from the edge in to the centre.
Look closely and the groove is not straight. Its walls wiggle, and that wiggle is the music, cut into plastic.
The needle rides in the groove, so the wiggling walls shove it side to side.
The record spins with a needle resting in the groove. It is a tiny diamond point on a thin arm (the stylus).
The record slides past underneath; the needle only moves across the groove.
Run a fingernail along a comb. Each tooth flicks the nail, and the flicks come so fast you hear a buzz. The groove walls flick the needle the same way.
Each wall of the groove carries one side of the stereo sound.
Stereo means two sounds at once, one for the left speaker and one for the right. Seen end on, the groove is a V, and its two walls sit at right angles.
The left wall's wiggles push the needle one way; the right wall's wiggles push it another. One needle reads both at the same time.
The needle wobbles a magnet between two coils, so a tiny electric copy of the wiggle comes out.
The needle's arm has a small magnet on its far end. The magnet sits between two coils of wire. They live inside the cartridge (the little box that holds the needle).
When a magnet moves near a coil, a little electricity flows in the wire. So every wiggle of the needle becomes a wiggle of voltage, only a few thousandths of a volt.
The same wiggle passes down the whole chain, so the groove's shape is the sound you hear.
Sound is air swinging back and forth. Fast swings are high notes; wide swings are loud ones. The groove is a drawing of that swing.
Every part copies the drawing into a new material: plastic, then needle motion, then voltage, then a speaker, then air. Nothing changes the shape, so the shape is what you hear.
Records are cut with the bass turned down, so the player has to turn it back up.
Bass means the low, deep notes. Deep notes make wide wiggles. Wide wiggles need a wide groove, and that eats space on the disc.
So since 1954 records are cut with the bass turned down and the high notes turned up. A small circuit called a phono stage flips that back. That is why a turntable needs a phono input.
The amplifier makes the signal big, then the speaker cone turns it into moving air.
An amplifier takes the tiny signal and makes it far stronger. That strong signal goes into a coil glued to the speaker cone, sitting next to a magnet.
This is the cartridge in reverse: electricity moves the coil, and the coil moves the cone. The cone pushes air back and forth in the shape of the wiggle. That moving air is the sound.