There are a lot of audio file formats. Here are the ones you encounter most commonly.
Recorded sound consists of fluctuations in electrical current coming off of a microphone or mixing desk. Before computers, you translated that current into tiny smooth wiggles in the shape of the groove cut into a vinyl record, or tiny smooth wiggles in the alignment of magnetic particles embedded in tape. Dragging a needle along the groove or running the tape over a magnet reproduces the original electrical current.
Examples: vinyl, reel-to-reel tape, cassettes
Pros: Analog formats can sound really great if your media are in good condition, and if you’re listening through a good sound system.
Cons: Analog formats can sound terrible if the media get scratched, dusty or demagnetized. You need to be very careful about physical degradation–every time you listen to a tape, you scrape a little bit of the coating off. You can’t make copies of analog media without introducing noise. And analog gear is expensive. Continue reading
Gödel, Escher, Bach by Douglas Hofstadter describes and defines the concept of recursion, and discusses its applications in computer science, consciousness, art, music, biology and various other fields.
Recursion is crucial to writing computer programs in a compact, elegant way, but it also opens the door to infinite loops and irreconcilable logical contradictions.
Computers can only do a few very simple operations consisting of flipping electrical switches on and off. You can represent numbers in patterns of the on-off states of sequences of switches. By flipping switches on and off in particular patterns, you can perform simple mathematical operations on the numbers. You can do more complex mathematical operations by stringing simpler operations together.
Writing a song is a lot like writing a computer program. They both require clever management of loops and control flow.
The simplest sheet music reads as a straightforward top-to-bottom list of instructions. You start on measure one and read through to the end sequentially. That’s fine unless the music is very repetitive, which most popular music is. The loop is the basic compositional unit of nearly every song you could dance to. The problem is that writing loops out sequentially is very tedious.
Rather than writing the same passage over and over, you can save yourself a lot of laborious writing by using repeat markers. They’re like the GOTO instruction in BASIC. Here are the first four bars of “Chameleon” by Herbie Hancock. This four-bar phrase repeats hundreds of times over the course of the song. You wouldn’t want to write them all out. With repeat markers, you don’t have to. Repeat markers give sheet music the topology of a clock face.