Groovy Discs: How do vinyl records work?
Since the rise of streaming over the past decade, music lovers have triggered a vinyl renaissance of sorts. When CDs phased the cumbersome 12″ discs out in the late 1980s, many people flogged their collections cheaply, assuming they would never return in vogue. Oh, how wrong they were! In 2023, the vinyl resurgence continued with 5.9 million units sold across the UK, beating the previous year’s total by 0.4m.
Music lovers of all ages are falling back in love with the analogue format and the immersive sleeve designs, but how do these groovy discs work? As the video below shows, large machines press the records en masse using the dimensions of a metallic master disc with etched grooves.
As the musicians arrange their instrumentals and vocal tracks, the sound is captured and recorded onto a master disc using a cutting lathe. These master discs, usually made of aluminium, contain analogue audio information (continuous, unlike the digital medium’s ones and zeros) in microscopic grooves. These grooves correspond to the variations in air pressure created by the original sound waves.
Once we have our freshly pressed record, a hole in the centre guides it onto the turntable’s spindle, which rotates at a precise speed, typically 33⅓ or 45 revolutions per minute (RPM). A weight-balanced stylus is dropped delicately into the grooves, vibrating in response to the variations in depth and shape. The good vibrations are then translated into an electrical signal by a cartridge, which is amplified and sent to speakers. From here, the vibrating air molecules hopefully reach your eardrums.
When were records invented?
In March 1857, the French printer, bookseller and inventor Édouard-Léon Scott de Martinville invented the phonautograph. A precursor to modern analogue recording devices, the intricate machine consisted of a diaphragm attached to a stylus that traced sound waves onto a soot-covered surface. This was the first step on the road to the record, but a few more years of Victorian innovation lay ahead.
In 1877, Thomas Edison, the famed American inventor behind the incandescent light bulb, invented the phonograph, widely considered the first commercially successful record player. The contraption worked using a rotating cylinder wrapped in a sheet of tinfoil. Heeding Scott de Martinville’s prior work, Edison captured sound using a diaphragm, transmitting the vibrations into a stylus, which made small indentations on the tinfoil to preserve the information. The phonograph could then reproduce the sound by retracing the indentations on subsequent plays.
Ten years later, Emile Berliner, a German-born American inventor, introduced the more familiar gramophone design. Unlike the phonograph’s cylindrical design, Berliner’s gramophone operated using flat discs, initially made of shellac, vinyl’s cumbrous older brother. These records featured grooves engraved into their surface, allowing increased efficiency in mass production and storage.
You can see the vinyl pressing process in the video below.
