How Sound is Recorded And Replayed From Vinyl
Vinyl records are the audio storage media of yesteryear. You can think of them as MP3 players that simply store sound using a different system: older hard disk drives use magnetism to store this information, reading and writing using an arm that sweeps back and forth across spinning magnetic plates. Flash-memory music players (read: iPods and their contemporaries), meanwhile, make use of transistor technology to store digital music, while compact discs have tiny pits pressed into the silver layer by a laser, which can be read by a CD player.
Records work in a very similar, if a more tangible, way to the latest playback devices, though the same principles behind 19th-century phonographs can be seen at work in modern turntables. The tiny grooves in the record vibrate a crystal in the stylus (needle) at the end of the arm as it moves across the record’s surface. The resulting microscopic jolts move a metal bar that squeezes a piezoelectric crystal, generating an electric signal. The signal is fed to the amplifier that interprets it, then sends it out to the speakers which replicate the original sound.
Today’s records are made of vinyl, pressed from a metal ‘mother’ that is cut using highly specialised machines. But even though the recording is of a much higher quality, you can still spin the turntable by hand to hear the record play without any intervention from modern technology.
Birth of the gramophone
In 1877, over a century before the dawn of digital music recording, Thomas Edison discovered that by attaching a needle to the diaphragm of a telephone receiver, a visual representation of the sound could be drawn when the needle vibrated along a cylinder covered in tinfoil. By attaching a horn and rotating the cylinder by hand, the sound could then be reproduced. Edison put his work on the phonograph on hiatus while he focused on electricity. In the meantime, Emile Berliner stepped in to create a more practical machine that used flat black discs, but could only play and not record. This was the gramophone and its records could be mass-produced via Berliner’s Gramophone Company. The basic format for sound recording remained the same up until the Eighties, when cassette tapes became standard.
World’s most-famous record
Probably the most-recognized record in the world (and beyond) is the Golden Record that was placed aboard the Voyager 1 and 2 spacecraft. It is a 30-centimetre (12-inch) copper phonograph plated with gold and on it is recorded sounds, music and greetings from Earth in 55 languages, including: Beethoven’s Fifth Symphony, “Hello from the children of planet Earth” in English and the sound of crickets and frogs. It is encased in an aluminium Jacket and includes a needle and cartridge along with instructions for any intelligent extraterrestrial life that happens upon Voyager on how to play the record. The record is designed to be played at 16-2/3 revolutions per minute – half the speed of the 33-1/3 standard for a commercial 12-inch vinyl. Since its launch in 1977, Voyager 1 has travelled nearly 18 billion kilometres (11 billion miles), making the Golden Record one of the few manmade objects to have left the solar system.