AUDIO ENCODING
We take for granted our ability to listen to digital audio. This is achieved by a conversion of audio frequencies and strengths into bits of data using what is called an digital-analog converter, or DAC. Analog audio is what we hear in the natural world and a DAC, along with a speaker, gives us natural audio from the digital world. The storage space required for digital audio is determined by the amount of natural audio represented in the file. All else being equal including the audio contained within, one digital audio file which is larger than another will also sound better. Various methods of compression, making a file smaller, can be used to reduce file sizes without necessarily reducing quality.
LOSSLESS COMPRESSION
One method of reducing file size without reducing quality is to remove repetition. This is similar to a zip file. One method of removing repetition which is easy to understand is to change text like “aaaaabbbbbb” to “5a6b”. The same can be accomplished with digital audio. One might note that if the original data was “abcd”, this would be represented as “1a1b1c1d” which is significantly longer. The methods used are much more complex but this complexity is part of why lossless compression is limited to only around 50 space savings usually. Methods which fall under the lossless audio compression banner include FLAC and Monkey’s Audio. These methods will make an audio file smaller without losing any quality at all and are excellent for archiving.
LOSSY COMPRESSION
Another method of audio compression to use which is more effective at saving space is called lossy compression. The main difference between lossless and lossy compression is that lossless audio compression also removes audio which humans can’t hear such as extremely high pitched audio. The audio isn’t exactly the same as the original audio but it is not usually noticeable by the human ear resulting in significant space savings on the order of 90.