Have you ever wondered how sounds on a vinyl disc are amplified through a record player? To explain this magical phenomenon, Ben Krasnow from Applied Science said, “The first step is to head down to the local music store and pick up a few LPs from the dollar bin.”
As Krasnow explains, when records are spinning, the stylist vibrate following the grooves of the vinyl disc which moves the magnets near a coil that generates electricity that gets amplified into the audio signal.
In order to further enhance our perception, the scientist used an electron microscope to create a stop-motion animation. The GIF animation is captured in 60 frames with a 50 micron spacing between each frame. The playback speed of the animated gif is about 1/400 actual speed if the record were playing.
Krasnow then threw back to the 60s, when RCA (Radio Corporation of America) released Capacitance Electronic Disc (CED). CED is an analog playback system that allows video and audio to be played back by embedding information in a high-level density groove similar to phonograph records. This technology allowed LPs to have a tighter track spacing with denser information. The method of storage on CED is also intensive and unique. When looking at a phonograph record the needle is vibrated by physical cuts in the track, whereas on CED, it is actually the depth of the track that makes the signal.
This sounds incredibly complicated to produce technically, and indeed it was. it took RCA almost 2 decades to figure out the correct way to produce Capacitance Electronic Disk. However, by which they have perfected it, LaserDisc, VHS, and videocassette had come out. CED was dead on arrival, this caused RCA to lose hundreds and millions of dollars.
The scientist also examined the storing method of digital format CD-ROM, he analyzed in his research, “.. instead of having a track vary in width or depth the track is predefined and then there’s pits and lands carved into it. Of course, the width of this is even smaller than the ridiculous capacitive electronic disks. It is down to about a 500-nanometer wide pit and I think the track spacing is about 1.6 microns.” As for a DVD, it has a 700-nanometer wide pit and it is near the limit of the resolution of the scanning electron microscope, at least for now.
The next time you attend a vinyl-only event, remember that these sonic signals of beats and melodies that we are receiving and grooving to are actually engraved into the discs as much as it is engraved in our brain.