digital-audio.org
Information centre for all about digital audioStorage
Once we have audio in a digital format it has to be stored somehow. In the early days this was in a real time format that was recorded and replayed only at the live speed. More recently however, a huge number of digital storage formats have grown up that store the sound as a computer file, which can be transported easily from device to device and compressed or expanded to suit the amount of storage space that we have available. This is where MP3 files originate, as well as many others.
Real Time
Real Time refers to a method of storage that exits with the sole purpose of being played back live, and also is not able to be manipulated unless it is played. The main example is the original Audio Compact Disc ( CD ), and another is Digital Audio Tape ( DAT ).
CD
CDs are one of the earliest digital audio storage formats, and have been around since the mid 1980s. They store audio data as a stream to be converted in real time as they are played back.
Tech specs for CD : Sample rate 44.1kHz, Resolution 16-bit
DAT
Digital Audio Tape was invented soon after CDs as a way of recording audio digitally in real time. The sound quality and performance is superb outperforming many newer recording mediums. It is based on magnetic tape, using a rotating head, like a VCR and is very robust for portable use. Unfortunately the manufacturing costs for the mechanism never really got low enough for general consumer use, but it is still used widely in professional environments.
Tech specs for DAT : Sample rate 48kHz, Resolution 16-bit
Data
Data refers to the storage of the audio as a data file on a computer or other solid state device such as a portable music player. It can be moved around, copied, compressed, modified by a computer program just as if it were a picture or document on a PC. The base format that is used in theses environments is called a WAV file. Computers ( PCs ) have always been able to store audio as a WAV file and it is a basic format that contains the entire audio data. It was invented originally to store the 'beeps' made by early PCs! However for any decent length of audio the files in WAV format can get very big, so when portable music players came along they needed to be compressed to fit on the smaller memory in such players. This is where most of the other formats that we know originated. There are two types of compressed file in use, Lossless and Lossy. Follow the link below for information on compression...
For more on Audio Compression click here