(WYTV) – How long is the groove on a compact disc?
The groove on a compact disc isn’t exactly a groove in the same sense as a phonograph record. It’s more like a path of bumps, bumps so small that only a laser beam could find them.
The laser beam reflects off the bumps differently than it does off the flat parts in between the bumps.
A sensor picks up that laser beam and sees them as a series of either “on” or “off” signals, then your CD player converts on and off to ones or zeros, 44,000 times a second and decodes these ones and zeros into music.
It takes a lot of bumps to convey all of this information to your CD player. The total distance covered by the laser beam when playing a CD is more than three miles.
How about a 12-inch-long playing vinyl 33 1/3 rpm record?
It too has one groove, a very sharp needle runs in the grove and vibrates, converting that vibration into sound.
How long is this grove?
The average length is 1,500 feet, not quite a third of a mile.
Sales of vinyl records will pass the sales of CDs this year for the first time since 1986. Why?
Some say they have a better sound.
What were we listening to on vinyl in 1986?
The top-selling albums included Madonna’s “True Blue,” Bon Jovi’s “Slippery When Wet” and the “Top Gun” soundtrack.
The old phonograph records spun at a constant speed, 33 or 45 or 78 revolutions per minute from the outside in. A CD plays from the inside out anywhere from 200 revolutions per minute up to 500 rpm as the laser beam approaches the outside edge.