[ELI5] Why did digital audio/cds allow for increased dynamic range and wider stereo separation compared to vinyl?
In: Technology
Vinyl records audio directly in a single groove. This means there are technical issues — how thick is the needle, how fast the disc is spinning, how precise is the manufacturing, how small of a feature the plastic can have, what is the needle’s inertia, etc. All of those things directly affect how precisely it can represent the signal. That’s also why not just any record player will do. How good is the driving mechanism and the quality of the needle matters.
In digital similar issues exist, but the important difference is that they don’t change how precisely the data is represented, they just affect how many bits we can squeeze into a given amount of room. We can allocate the available bits in any way we want. So if you want to put 24 bit, 192 KHz audio on a CD, you can. You won’t fit a whole lot of it, but that’s the only issue.
For stereo, since there’s only one groove, stereo is encoded at an angle. The incorrect ELI5 explanation is that one channel is left/right and the other is up/down. The real explanation is that this is that both are at a 45 degree angle from the vertical.
Meanwhile, in digital we can just interleave channels. Have a track that goes “5ms of channel 1, 5ms of channel 2”. You can have as many as you like and the separation is perfect because they have nothing to do with each other.
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