How Does the Sound Come from a Record?
The vibrations of sound made by a person’s voice or a musical instrument are recorded in the wavy groove on a phonograph record. When you switch the record player on, the turntable spins the record at just the right speed. A needle at the end of the tone arm follows the sound groove and vibrates.
The vibrations set up a weak electrical signal in the cartridge on the tone arm. These signals are amplified, or made stronger, by the amplifier. At this point, the loud-speaker turns the strong electrical signals into sound waves that you can hear.
While the technology used in recording and playback devices improved steadily, record players are still based on the needle in groove concept. One of Berliner’s breakthroughs, the turntable, has been improved and mechanized to spin the record with the aid of a belt or a direct drive system.
As the record turns, a stylus ‘reads’ the grooves. This cone shaped needle hangs from an elastic band of metal and is made from a hard material, usually diamond. The stylus is set at one end of the tone arm, which is set at the side of the turntable, parallel to the record, and moves across the record while the stylus follows the spiral groove.
The stylus picks up vibrations as it moves through the grooves of recorded sound, and those vibrations travel along the metal band at the end of the tone arm, to wires in a cartridge at the end of the arm.
A coil in a magnetic field turns the vibrations into electrical signals, which are carried along wires to the amplifier. These boosted signals are finally turned back into sound through the speakers, producing the sounds and music recorded on vinyl records.