Recorded sound

Traditional audio technology has its foundations in recording. Real world sound signals are captured by a microphone, mixed and processed, then mastered into a finished form. A piece of music or sound effects track created this way is fixed. Each time it is replayed the form remains the same. In contrast, procedural audio may be different each time it is played. Recorded audio consists of data where the values are a time sequence of amplitudes, typically about 44,000 per second. The samples are replayed from start to finish in the same order and at the same rate as that in which they were recorded. We call this sampling, a technology that has been common for several decades now. With recording we have always had a distinction between the data and the program or device that replays it. We think of MP3s as the songs and the MP3 player as an application device that reproduces the recorded sound by turning the data back into sound. Very differently, procedural sound may not need to store any data at all! In fact procedural audio can be though of as just the program, which is another way of saying that the process entirely captures the intended result. The program is the music or sound, it implicitly contains the data and the means to create audio. For an introduction see Pohlmann[23].