how music is read on cds and cassettes


It boggles me. Like lasers are involved somewhere? How do they get the voice embedded? HOW?!

In: Technology

To put it simply, any information (text, sound, video, math, pictures, etc) can be written in binary code, AKA Zeros-and-ones. How those 0s and 1s are translated back into a sound or an image depends on how they are translated, and by what or who is doing the translating.

Think of it this way: if i gave you a book that said 000=A, 111=B, 010=C, what would 010 000 111 spell? It would spell “Cab”.

Now, lets say that book also contained 01 codes for every musical note, at every pitch, played by every known instrument and every electronic synthesizer, and then handed you a scroll filled with millions upon millions of 0s and 1s. Could you eventually translate them into sheet music? Theoretically, so long as you didnt kill yourself before completion, yes you absolutely could.

Then the sheet music could be played by an orchestra. TAdaaaa! Binary code to real, listenable music.

A CD player does this in a matter of thousandths of a second. A laser skims the bottom of a CD and there are microscopic divets and bumps on the CD. A bump is seen as a 1, a divet is seen as a 0. The laser reacts every time it hits one of these, telling the cd player’s processor that 0s and 1s are coming in en masse. That computer inside the player then translates these in essentially real-time to the audio that is played out of the speakers. Yes, it’s impressive as fuck of a technology, especially considering its completely obsolete at this point and yet still so mindboggling to comptehend how humans figured it out in the first place.

Tape works the same way. Just instead of a laser hitting bumps, a magnet reacts to polarity push or pull on the tape as 1 or 0.

Thats the magic of binary; 1 or 0, on or off, red or blue, bump or divet, car or train, apple or orange… it doesnt matter. 2 values can be used to code out literally any and all informatiokn so long as there’s a way to translate it back.