It's About Time, It's About Space
"We're in the process of major change in the world as the electronic technologies developed throughout the century become mature and increasingly intertwined and meshed with every aspect of our daily lives. New tools and concepts are leading to new approaches to art and universal possibilities for human creativity."
-Joel Chadabe,
-President, Electronic Music Foundation

Over 100 years ago audiences were first introduced to the silence of moving pictures on a big screen. And just over 60 years ago a small box began to appear in our homes, depicting pieces of the world as fuzzy dots glowing on a black and white tube. Yet today film without sound, or television without color, is unheard of. Michael Rush (1997) points out that the Web began in silence, just like moving pictures. And Jason Alexander (1997) compares the technical advancements of the Web, which began in black & white (or green & black), to that of television, which now appears as a richly colorful, stereophonic, surround sound medium.

These comparisons are made to portray just how young the field of Digital Audio really is. This may not be far from the truth considering one of the first digital technologies (the Compact Disc Player, born in 1983) hasn't had its 20th birthday yet (Schoenherr, 1998). And in the last five years alone an avalanche of technical developments have bombarded both media developers and their audiences who unceasingly thirst for more.

A Really Slow Game of Tag
My discussions so far seem very Webcentric. What about CD-ROM developers and interactive software? Well, as Kristof & Satran (1995) point out, media rich files are oftentimes reserved for the elite--the high capacity delivery mediums such as CD-ROMs. Web developers meanwhile are left out in the cold, having to forage for scraps of sound and blocks of time. If they are lucky, they may embrace the warmth of a string quartet for a few seconds as a reward for their hours of patience and solitude. Why are they treated this way? Where did they go wrong? The answer to at least one of these questions is space, and time.

The moving vibrations of air that we call sound travel at 1,129 feet per second, or 770 miles per hour (Ebersole, 1992). These audible vibrations can't readily be loaded into your computer or onto your Web page. To be amplified, shaped, stored, or transmitted, they must first be converted to another form. Although transducers (microphones) hold the stage for the mechanical/electrical conversion of sound, binary digits or bits (1's and 0's) hold the key for digital sound conversion.

Snapshots = Frequency
Just like working with motion pictures (still photos = movies), to digitize sound it is necessary to take a series of "snapshots" called samples. Since air moves in waves (very fast waves), the accurate sampling of sound requires following the Nyquist Theorem (Lehrman, 1996). Basically this states that you need to take 2 "snapshots" (samples) of the fastest wave to get a good (accurate) sound reproduction. (This is like setting your camera to a fast shutter speed to capture a picture of a hummingbird in flight.) Since the fastest waves that we can hear (on a good day) vibrate 20,000 times per second, we need to take 40,000 "snapshots" every second! But, to play it safe, the recording industry has decided to use 44,100 samples per second as the recording standard for CD quality sound (or 44.1 KHz).

Length  = Bits
Each of these "snapshots" is stored in the digital device by a "word" made up of 1's and 0's. This "word" may be 8 bits long (eight 1's or 0's), or it may be 16, or 32, or a variety of other popular word lengths (16 bit is the industry standard for CD quality sound). This "word" describes one finite moment of time that comprises this wave form or sound. It is the combination of all of these "words" that have the potential to reproduce a copy of the original sound, just as a series of still photos is used to create movies.

Space
Finally, after all of that, we're ready to get back to our original problem. (Not quite, but we're almost there.) Taking 44,100 snapshots per second with 16 bit words would mean that a 1 minute audio clip could be reproduced with the help of 42,336,000 bits! And that's not even in stereo. So space becomes one of our problems when working with digital audio files.

Time
And then there's time. With a 28k modem (Audiohost, 1997), you can expect a transfer rate of  between 1.5 and 2.3 Kbytes per second (2.3 Kb = 2,300 bytes). (For the less computer oriented, there are 8 bits in a byte, 4 bits in a nibble, and 2 nibbles in a byte. Trust me on this one.)  At this speed, how long would 1 minute of CD-quality sound take to download over the Internet? So that you don't have to do the math, our problem becomes apparent with the chart below:

Table of Digital Audio Transfer Rates

To wait 76.7 minutes to be able to hear one minute of CD quality sound just kinda takes the fun out of being online. And then there's the problem of interactivity. If you add CD quality sound to your Web page you are guaranteeing a new level of media interinactivity!

Or you could always think of it this way. If you weren't using a computer, and you had to wait 76.7 minutes for a sound to travel through the air to reach you, the source of that sound would have to be some 986 miles away! This sound problem doesn't bring the World Wide Web closer, it pushes it farther away.

Test Your InterInactivity
Tired of always being in the game? Wish you could take your turn just sitting on the sidelines? Now is your chance. The following files were recorded at 16 Bit, 11 Khz. Test your computer to see if it's slower than most. Click on one of the files below and join the ranks of thousands who have experienced the excitement of just sitting there while your computer does all the work. Try not to feel too badly as your processor wheezes and strains as it tries to obey your latest command. In fact now would probably be a good time to get something to drink...
 

What Else Could Go Wrong?
You'd think that time and space have presented enough problems, but there are still more. Digitized audio comes in many flavors, formats, shapes, and sizes. The information can be coded in a variety of ways, few of which are compatible with each other (Alexander, 1997). And besides that mess, there are different platforms (PC? Mac?) for these files to run on. These require programs called plug-ins to get things to work together. And, you guessed it, there are a variety of these, too!

Why Bother?
Well, do you remember our elite CD-ROM developers? Many of these designers believe that sound contributes more than 50 % to an interactive experience (Kristof & Satran, 1995). Even if presented in a simple format, music and sound effects can evoke a mood or even help to get a point across (Heid, 1997). And besides, if we don't make an attempt to move forward, digital audio will be stuck in the land of silent movies and black & white TV. So where do we go from here?

Solutions
The following pages present a look at four of the rapidly advancing technologies that are attempting to catapult Digital Audio into the next millennium (MIDI, MP3, BeOS, & RMF), as well as some ideas about how to use these (or any other technologies) to create better interactive mediations.

Main Menu

Have you had enough? Or are you thirsty for more?
If you want more info about Digital Audio, these sites will help to wet your appetite.
AUDIO - Sound & animation for the Internet at Audiohost.com.
BOOKS - A Book source for computer music and digital audio technology.
EMF - Information resource about the history and development of electronic music.
HARMONY - Internet resource for musicians at Harmony Central.
HISTORY - Explore the history of recording technology at the University of San Diego.