4.5: section 3: data representation: representing images and sound

• the number of samples taken per second measured in Hertz - increasing sampling frequency increases sound quality but also file size

• the level of detail recorded from an analogue signal • the number of bits available for each sample • n amount of bits provides 2^n combinations of colors or audio gradations

sample frequency(Hz) x sample resolution(b) x time(s)/8

-a standardised protocol, digital interface and connectors that allow digital instruments and computers to communicate

• event messages are stored in MIDI files • these messages specify how an instrument should be played and what notes should be played • include note duration, pitch, volume change, vibrato and temp synchronization

• creates standardised way for musical sequences to be saved • they can be used and shared across different devices and applications • records instructions on how to play instruments rather than analogue sound so outside disruptions wont be recorded • midi files can be up to 1000x more space efficient than other audio files • allows for the easy manipulation of single instrument • one midi artist can produce the same amount or work as an ensemble

• the sampling rate of sound should be at least twice the frequency of the highest frequency in the sound wave • humans hearing frequency = 20-20,000 Hz • audio sample rate should be at least 40,000Hz • typical audio is sampled at 44,100 Hz