ILLUSTRATIONS Marcos de Lima
In 1877, the American inventor Thomas Edison, understanding that sound is the vibration of particles that propagate through a medium – as in waves through the air – developed a technique so that these waves could be recorded. Thus came the phonograph, the first device to use a needle and an amplifier to reproduce sound. The vinyl record was born years later, in the 1940s, using almost the same technique as its predecessor.
1. FIRST MOLD
To produce a vinyl record, several steps are necessary: first, the music is recorded in a studio and stored analogically (on tape) or digitally (on HD). Then, at the vinyl factory, a machine engraves this content onto a polished aluminum disc coated with lacquer (a resin). By “engraving”, we mean making grooves in the material
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2. THE BIG SECRET
The grooves, essentially, are printed sound waves. It might seem bizarre that an entire song would fit on a single wave, but that’s right. The most common, however, is the impression of two separate waves that complement each other – what we call stereo. As the groove in the vinyl is V-shaped, each wave is printed on one side
3. PRINTING DISCS
The aluminum disk is plated with silver and nickel, forming a metallic layer that separates from the original disk. This layer is the metallic master, a mold to produce vinyl records on an industrial scale. It is fitted in machines that apply a force of 100 tons over molten PVC “biscuits”, recording the vinyls. Each disc takes less than 30 seconds to make
4. MUSIC MACHINE
To reproduce vinyl, you need a record player, a device known here in Brazil as a record player. This equipment has a base where the circular platter is and a pin in the center to hold the vinyl. The platter rotates with the help of a drive belt and an electric motor that makes the disk rotate clockwise.
5. FIRM END
The needle – made of a very resistant material, such as sapphire or diamond – has a cone shape and is responsible for reading the grooves. The record can rotate at two speeds (33 or 45 revolutions per minute), which can be adjusted on the record player. As it rotates, the tip of the needle gently travels along the grooves etched into the vinyl, vibrating in accordance with the microscopic relief.
6. ELECTRIC JOURNEY
The needle’s vibrations go to the phonocaptor capsule, at the end of the arm. It contains a magnet and a coil. When the vibrations make the magnet move, they interfere with the magnetic field generated by the magnet, transforming mechanical energy into electrical signals, which pass through the coil and travel along the wires along the arm.
7. UP THE VOLUME!
When playing on a loudspeaker, what happens is the reverse process: the electrical signal passes through the coil in alternating current, generating a magnetic field that is attracted and repelled by the magnet many times per second. This movement causes the diaphragm, the concave structure made of plastic or paper, to vibrate, which causes the air to vibrate, creating sound waves.
SOURCES Book Vinyl: A History of the Analogue Recordby Richard Osborne, and websites National Geographic, How Stuff Works, Explain That Stuff It is reddit