[ELI5] Why did digital audio/cds allow for increased dynamic range and wider stereo separation compared to vinyl?
In: Technology
On a vinyl record, the sound is recorded in grooves molded into the vinyl. On very quiet sections, the groove is almost a straight line. On louder sections, the groove zigzags back and forth noticeably.
Vinyl has limited dynamic range because if the sound too quiet, the movements of the groove are too subtle for the needle to pick up, and if the sound is too loud, the groove would touch the groove next to it and so the record would skip whenever the needle reaches that point.
On a vinyl record, stereo is achieved through a process called “mid-side encoding” or “joint stereo encoding”. Basically, to produce stereo records that could still be played by older mono turntables, they devised a scheme whereby vibrations of the needle in one direction would represent “left plus right”, vibrations in another direction would represent “left MINUS right”. An old mono turntable would only be able to play the L+R signal… while circuitry in a stereo turntable would perform some analog math to reconstitute separate L and R signals from the L+R/L-R. But since everything involved here is analog, it’s less than perfect and can only achieve so much.
In digital media, since we didn’t have the old mono compatibility issue to think about, we can store the left and right signals as-is. And since digital media is all ones and zeroes rather than a physical groove in a record, we don’t have to worry about tracks physically touching, so we could give a digital format any amount of dynamic range we want.
Latest Answers