My fellow presenters were Brandon Brown ( ) and Irena Romendik ( ).

» Brandon's presentation on MIDI

With the advent of MIDI, scoring software and digital audio, computers have begun to play an important role in helping composers produce and record music. Yet some researchers have given computers an even greater role in music composition -- that of the composer itself. Here is a brief survey of some experimental ways in which computers have been programmed to compose music based on raw data rather than a human composer's vision.

1. Atmospheric & Cosmic Waves: Music to (Some)one's Ears

» VLF Audio Stream
http://spaceweather.com/glossary/inspire.html

Within the 100 to 2400 Hz radio band (far below the frequencies at which AM radio is broadcast, between 540 kHz and 1.6 MHz) live a group of very low frequency radio waves generated by the earth itself, usually as a byproduct of lightening strikes. (Lightening strikes the earth 100 times a second.) Using a specially calibrated "radio" -- really, just an antenna and an amplifier -- one can hear these radio waves.

The sounds heard can be classified as "tweeks," "whistlers" and "sferics", each generated as radio waves are dispersed by the Earth's atmosphere in different ways. Here are NASA's definitions of each sound:

Listen (RealPlayer)
Sferics, short for "atmospherics", are impulsive signals emitted by lightning. They sound like twigs snapping or bacon frying.

Listen (RealPlayer)
Tweeks are sferics that travel considerable distances through the ionosphere -- a "dispersive medium" where low frequencies travel slower than high frequencies do.

Listen (RealPlayer)
Whistlers are sferics that are dispersed even more than tweeks. The sound of a whistler is a musical descending tone that lasts for a second or more.

» Listen Live to the Earth's VLF Emissions!
http://science.nasa.gov/audio/inspire/inspire.m3u (RealPlayer/WinAmp)
http://science.nasa.gov/audio/inspire/inspire.mov (Quicktime)

» More VLF Sounds
http://image.gsfc.nasa.gov/poetry/inspire/advanced.html

» Earth Songs (Related Article)
http://science.nasa.gov/headlines/y2001/ast19jan_1.htm

Similar sounds can be found in deep space in the form of plasma waves. They have been recorded by many spacecraft and translated into audio form.

» Music Out of This World (nasa.gov)
http://www.nasa.gov/releases/2002/02_207.html

» Sounds from Space (uiowa.edu)
http://www-pw.physics.uiowa.edu/space-audio/sounds/sounds.html

» Galileo Plasma Wave Investigation: Observations At Ganymede (nasa.gov)
http://www.jpl.nasa.gov/galileo/ganymede/pws.html

» Plasma Waves Associated with the Bow Shock of Jupiter (uiowa.edu)
http://www-pw.physics.uiowa.edu/plasma-wave/tutorial/voyager1/jupiter/bowshock/text.html

» Cassini Jupiter Flyby (uiowa.edu)
http://www.jpl.nasa.gov/jupiterflyby/gallery/gl_pages/rpws_release5.html

These collections of snaps, crackles and pops evoke static more than Shostakovich. But they have inspired Dr. Don Gurnett, a physicist at the University of Iowa, to collaborate with the Kronos Quartet on a composition inspired by the sounds of these interstellar plasma waves. The work has been performed recently at the San Francisco Jazz Festival, with visual effects culled from Gurnett's images by the same man who designed the set for the Rolling Stones' recent tour.

» "Sun Rings"
http://www-pw.physics.uiowa.edu/space-audio/KronosSounds.html

Not only does the Earth broadcast VLF frequencies -- so do many of the devices that surround us. In fact, it is an old computer trick to use the processing cycles of a slow CPU to broadcast songs on AM freqencies. Some Slashdot memories:

• "I remember listening to Christmas songs on an AM radio sitting on the console of an RCA 301 in 1965."
• "Make a Commodore 64 play "A Bicycle Built For Two" by grinding the stepper motor back and forth on the read/write head of a 1541 disk drive. Saw this done back in 1987."
• "My first exposure to computers was on a high school field trip to the old DEC factory in Maynard MA (in an old textile mill) where they were making early minicomputers - PDP 8's with 12 bit words, Link 8's etc. in 1967. During this trip we were shown a Link 8 with an AM radio sitting on top of the machine playing Greensleeves based on the program running in the machine at the time."
• "I remember keying (switching?) in 'The fool on the hill' from a Creative Computing mag into my Altair's front panel. I took about an hour, so I would let it play for the rest of the day."

Berke Durak's extremely technical description of his this can be (sort of) done with modern machines:
http://perso.wanadoo.fr/berke/tempest/

You can also generate AM broadcasts with your monitor!
http://www.erikyyy.de/tempest/

This is based on a principle (EMF leakage) which has implications far beyond the scope of this report. For instance, you can eavesdrop on other people's computers by monitoring their EMF radiation. For more on this topic, check out
http://rr.sans.org/encryption/TEMPEST.php

The relationship between math and music is well-documented; Western composers have known for centuries the basic mathematical principles employed in musical composition.

» Math And Music
http://www.edenpr.k12.mn.us/ephs/ArcadiaWeb/Math/mathandmusic.html
http://metamath.flatline.de/mpegif/mmmusic.html

Some scientists have been tempted to remove the human element entirely by translating data directly into musical scales, with varying degrees of success.

A popular example is translating fractal forms, usually represented visually, into sound pieces.

» Fractal Music Gallery
http://thinks.com/sounds/fractal.htm

John Greschak creates musical compositions based entirely on the mathematical properties of Platonic solids.

» Music By John Greschak
http://www.greschak.com/index.htm

Yes, you too can create your own musical compositions based on pretty much anything.

» A Musical Generator
http://www.musoft-builders.com/links/amg.shtml