Digital audio is just another recording medium like cassette tape and vinyl records. Cassette and vinyl records had a dymanic range (loudest volume / softest volume) of 60dB to 80 dB.

When the audio CD format was being developed, the Sony and Philips people decided to encode each audio sample as a 16 bit number which have a range of -32768 to 32767.

With 16 bit audio, the loudest signal can have an amplitude of 32767 and the softest signal an amplitude of 1 resulting in a dynamic range of a bit over 90 decibels which would seem sufficient.

For certain applications, people are using 24 bit integers and 32 bit floating point values to store audio data.

When we sample a signal, then quantize the samples and code them as binary values, we create a Pulse Code Modulation (PCM) signal. This PCM signal is a long string of numbers.