What makes something digital? For our purposes, we'll assume that information can be stored in two formats: Analog and Digital. If you wanted to store a novel in Analog format, you could write it on a piece of paper with a pen. To store it digitally, you might type it into your computer's word processor and save it as a file. A word processor file is composed of a series of 1's and 0's (or ON's and OFF's) that are called bits. By combining a very large number of bits, we can record letters, words, sentences, and paragraphs.

What is the difference between the Analog novel and the Digital novel? Anyone can read the Analog novel from the piece of paper. To read the Digital novel, the reader needs to have a computer that has the right software to convert the bits that are in the file into a format that can be read. The Digital novel is a little more cumbersome to create and read. The Analog novel takes up a lot of space and the paper will probably degrade over time. The Digital novel can be saved more permanently, and your computer can hold thousands of novels in the same amount of space that might be taken up by two or three Analog novels. If you want to share your Analog novel, you will have to copy it by hand or photocopy it. Either of these methods is time-consuming and will produce a copy that is of lower quality than the original. Your Digital novel can be copied almost instantly, and, since it is composed of bits, the copy will be exactly like the original. To send your Analog novel to someone else, you will have to mail it (which could take weeks). Because we live in a world that is wired for the transmission of digital information, you can send a copy of the Digital novel to someone thousands of miles away in a few seconds.

Are there drawbacks to Digital information storage? Originally, some people complained that the quantification that takes place in converting something into 1's and 0's removed the more subtle nuances from it. Using our novel example, suppose the Analog novel was written in an elegant and intricate script, while the Digital novel was composed in standard typing font. If the Analog novel was replaced by the Digital novel, the content would be the same, but the aesthetically-pleasing calligraphy would be lost. Since digital technology and storage capacity have become more sophisticated, it is now possible to get the benefits of the Digital format and retain the nuances that give the Analog format its charm. Using an even larger number of bits and intelligent software, it is possible to compose your novel with paper and pen, then run it through a scanner to convert it into a digital file that will preserve your beautiful handwriting forever.

What does this have to do with music? Sound, like text, can be recorded and stored in these two formats. Analog recordings are made to magnetic tape and vinyl. Digital recordings can be made and copied on anything that can record bits (digital tape, a computer hard drive, or a floppy disk). You probably remember the outcry in the mid-80s when Compact Discs began to replace vinyl LPs and cassettes in music stores. This was the beginning of the movement of digital audio into the consumer marketplace. If you own and play CDs, you are already a part of the digital audio world. The benefits in our example of the Digital novel also apply to digitally stored audio; CDs are both smaller and more durable than vinyl LPs.

Originally, audiophiles claimed that the sound difference between CDs and LPs was significant. Technology has now progressed to the point where Digital recordings can produce Analog-quality sound by capturing the sound information in a very, very large number of bits. The only drawback to this advancement is that the resulting file requires a huge amount of hard drive or disk storage space.

Luckily, there is a way to make that giant sound file take up less space... compression. The next section of this primer delves into digital audio compression.