Electromagnetism and sound
a great intro by Nicolas Collins
There is a beautiful symmetry to the principles of electricity that are most commonly used to translate acoustic sound into an electrical signal and then back into sound again. Inside every dynamic microphone (such as a typical PA mike) is a lightweight plastic membrane affixed to a coil of fine wire encircling a cylindrical magnet. Madonna sings, and her sound waves jiggle the membrane, which moves the coil in the field of the magnet, generating a very small electrical current. This current is amplified, equalized, flanged, reverberated, compressed, and finally amplified even more before being sent back out to a bigger coil wrapped around an even bigger magnet. Now this shimmering electromagnetic field pushes and pulls against the big magnet, moving a paper cone back and forth, producing sound waves of… a louder, possibly improved, Madonna.
British computer scientist and musician John Bowers has developed a beautiful electric instrument, evoking the spirit of nineteenth-century electrical experimentation out of nothing more than a speaker, some batteries, wire, and scrap metal.
Hook up the circuit shown in fi gure 5.1. Clip one end of a test lead to one terminal of the speaker (it doesn’t matter which). Clip the other end to the “+” or “–” terminal of the battery (again, it doesn’t matter which one). Now tap the loose end of the second clip lead to the open terminal of the battery. The speaker should pop in or out from its position of repose. If it doesn’t, the battery is dead, speaker is blown, or/and one or both of the clip leads is faulty; replace suspect elements until you hear and see the speaker jump. Disconnect the clip and the cone should pop back to its original position. Reversing the polarity of the battery will change an in to an out or vice versa: the cone that popped out should now suck in.
What’s happening? Passing the battery current through the speaker coil (which is attached to the paper cone) creates an electromagnet that interacts with the speaker’s fixed magnet (attached to the metal framework) and moves the cone in or out, depending on the polarity of the battery and resultant magnetic field.
Connect one lead from a battery terminal to a speaker terminal. But this time, instead of connecting the second lead directly from the battery to the other speaker terminal, clip it between the speaker and a metal file or a chunk of some conductive metal:
a pie tin, a cookie sheet, scrap copper flashing, an anvil, a piece of girder, a brake drum, a frying pan, etc.—the rougher or more corroded the metal surface, the better. Clip one end of a third jumper lead to the other terminal of the battery and the other end to a nail, bent paperclip, knife, or other pointed piece of conductive metal.
Touch the nail to the metal. When it contacts the metal, the nail completes the circuit, sending current through the speaker coil, and making the cone jump, as before. Now scrape the nail across the metal: as the contact is broken by irregularity of the surface, the speaker emits scratchy, percussive sounds whose character is quasi-controllable through hand gesture.
Drawing the nail across a file yields sounds curiously like those of turntable scratching. You may notice sparks as the contact is made and broken, and the battery will probably get warm—the speaker coil is almost a short circuit, and sucks a lot current from the
battery. Avoid holding the nail on the metal for an extended period of time—loudspeakers get hot and bothered when presented with a steady DC voltage, so it’s better to send them shorter pulses.
Instead of using the nail and file, you can clip the leads to two paperclips, washers, coins, aluminum pop-tabs, or loops of copper wire that you place inside the speaker cone. The cone jumps when contact is made, breaking the contact for a moment, then the metal
bits fall against each other and the process starts all over—a mechanical oscillator and the beginning of what Bowers calls “The Victorian Synthesizer”.
Hold two contacts close together against the speaker cone: by varying your touch and the location on the cone, you can change the pitch and rhythm of the buzzing sounds.
You can line the cone with aluminum foil or apply metal tape , connect one lead to the foil or tape and the other to a fl ip-tab or other light metal fragment. The tab gets thrown up from the foil or tape, breaking and making contact as before. Multiple
speakers can be wired in series (like those frustrating Christmas lights from our childhood) or parallel, with contacts resting in each cone, so they interact to produce more complex rhythms. You can substitute a tilt-switch (see chapter 16) for the aluminum tabs as another way of using the speaker’s own movement to turn on and off the current.
Sound doesn’t end at the loudspeaker, it starts there. You can use your hands, bowls, or toilet plungers to mute and resonate the sound further. Put gravel, loose change, or dried lentils inside the cone for additional rhythmic accents.
The Piezoelectric Effect
Another common principle of reversible sound translation is the “piezoelectric effect,” which depends on the electrical properties of crystals, rather than electromagnetism: bang a crystal with a hammer and it will generate a pretty sizeable electrical signal (enough to light a flashlight bulb); conversely, if you send an electrical current into a crystal it will twitch.
Piezoelectric disks, made by bonding a thin layer of crystal to a thin, flexible sheet of brass, are everywhere today, inside almost everything that beeps: appliances, phones, toys, computers, etc. Because they are manufactured in huge quantities they are
incredibly cheap, and they happen to make even better contact microphones than they make speakers. Drum triggers and commercial contact mikes are oft en made from piezo disks and sold at absurdly marked-up prices.
the disk should appear as a circle of gold- or silver-colored metal, with a smaller circle of whitish crystal within. Depending on the design, there will be two or three wires connected to the disk. One will always be connected to the metal
portion, somewhere near the edge; this we will call the “ground” connection. One will connect to the main part of the inner crystal circle; this we will call the “hot” connection. In some cases there will be a narrow, tongue-like shape differentiated within the crystal, to which the third wire connects; this we will call the “curious but unnecessary” (CBU) connection.
Every audio connection consists of two parts: the signal and a ground reference.
In the case of a contact mike the signal comes from the white part of the piezo disk, while the ground is the brassy bit; on the plug the tip carries the signal and the sleeve
Invented by Édouard-Léon Scott de Martinville in 1859
The phonautograph is the earliest known device for recording sound, it transcribed sound waves onto paper or glass, but the device was not able to play it back.
Several phonautograms recorded before 1861 were successfully played as sound by optically scanning them and using a computer to process the scans into digital audio files.
A BRIEF TIMELINE OF SOUND ART
The phonograph, invented by Thomas Edison in 1877, could both record sound and play it back. The earliest type of phonograph recorded on a thin sheet of tinfoil wrapped around a grooved metal cylinder, later on wax.
Futurism was an avant-garde movement founded in Milan/Italy in 1909 by the poet Filippo Tommaso Marinetti. The Futurists practiced in every medium of art including painting, sculpture, music ...
They got rid of melodies and other traditional elements of music and focused on noise. They held the first experimental music concerts in the world and are the Pioneers of electronic music.
Luigi Russolo's "Intonarumori"
The Futurist painter and composer Luigi Russolo published the musical manifesto “L’arte dei rumori” in 1913 elevating urban noises to the level of an art.
He designed and constructed a number of noise-generating devices called Intonarumori.
Dada was an art movement of the european avantgarde, that began in 1916 in Zuerich Switzerland at Cabaret Voltaire. dada was designed to be misunderstood, it defied all the expectations the world had for art. it was the complete opposite of what art stood for, it tried to insult and provoke.
"..it was a storm that broke over the world of art as the war did over the nations. " Hans Richter
Hugo Ball was a German author, poet and wrote the dada manifest. He was a pioneer in the development of Sound poetry.
Kurt Schwitters was to bourgeois for berlin's dada, so he founded merz in hannover. He was working with poetry, sound, painting, sculpture, graphic design.
Musique concrète is a form of experimental music that exploits acousmatic listening, meaning sound identities can often be intentionally obscured or appear unconnected to their source cause. It can feature sounds derived from recordings of musical instruments, the human voice, and the natural environment as well as those created using synthesizers and computer-based digital signal processing.
Schaeffer is considered one of the most influential experimental, electroacoustic and electronic musicians, having been the first composer to utilize a number of contemporary recording and sampling techniques that are now used worldwide by nearly all record production companies. In 1948, Schaeffer produced the first piece of Musique Concrete by recording, manipulating and arranging a variety of sound produced by trains. He established the first purpose-built electroacoustic music studio at the RTF (radio television france), which quickly attracted later to become notable composers.
"etude aux chemins de fer"
Stockhausen's first "Musique concrète" piece was realized in Pierre Schaeffer's studio in Paris. Back in Germany he established his own Studio at NWDR in Cologne, mostly because of conceptual differences.
"Kurzwellen (Shortwaves)" Kurzwellen (Short Waves), for six players with shortwave receivers and live electronics, is a composition by Karlheinz Stockhausen, written in 1968.
"Gesang der Jünglinge (Song of the Youths)" The work, routinely described as "the first masterpiece of electronic music"
It is significant in that it seamlessly integrates electronic sounds with the human voice by means of matching voice resonances with pitch and creating sounds of phonemes electronically.
Fluxus— founded by George Maciunas, — meaning "flow, flux" (noun); "flowing, fluid" (adj.)— is an international network of artists, composers and designers noted for blending different artistic media and disciplines.
John Cage was an American composer, music theorist, writer, philosopher, and artist. His work was heavily inspired by eastern religions, like Zen-Buddhism and Hinduism. The I Ching, an ancient Chinese classic text on changing events, became Cage's standard composition tool.
4'33" - In the work, no intentional sounds are made during its duration. The composition is not silence, but rather the sounds of the environment heard by the audience during the performance. The noises the audience is making during the concert, are just as much a part of it, as anything the composer wrote down. The frame of the piece is time.
Imaginary Landscape No. 4 - For this work, 2 performers are stationed at each radio, one dialing the radio-stations, the other controlling amplitude and timbre.
A prepared piano is a piano that has had its sound altered by placing objects (called preparations) on or between the strings.
The invention of the "prepared piano", per se, is usually traced to John Cage. Cage first prepared a piano when he was commissioned to write music for "Bacchanale", a dance by Syvilla Fort in 1938. For some time previously, Cage had been writing exclusively for a percussion ensemble, but the hall where Fort’s dance was to be staged had no room for a percussion group. The only instrument available was a single grand piano. After some consideration, Cage said that he realized it was possible “to place in the hands of a single pianist the equivalent of an entire percussion orchestra ... With just one musician, you can really do an unlimited number of things on the inside of the piano if you have at your disposal an exploded keyboard”
“If something is boring after two minutes, try it for four. If still boring, then eight. Then sixteen. Then thirty-two. Eventually one discovers that it is not boring at all.”
"The first question I ask myself when something doesn't seem to be beautiful is why do I think it's not beautiful. And very shortly you discover that there is no reason."
The cut-up technique (or découpé in French) is an aleatory literary technique in which a text is cut up and rearranged to create a new text. The concept can be traced to at least the Dadaists of the 1920s, but was popularized in the late 1950s and early 1960s by writer William S. Burroughs, and has since been used in a wide variety of contexts.
The technique and Burroughs had a big influence on music and sound art
is a Canadian composer, saxophonist, media artist and dancer. His best known project is Plunderphonics, the practice of making new music out of previously existing recordings (see sound collage and musical montage).
A plunderphone is a recognizable sonic quote, using the actual sound of something familiar which has already been recorded. Whistling a bar of "Density 21.5" is a traditional musical quote. Taking Madonna singing "Like a Virgin" and rerecording it backwards or slower is plunderphonics, as long as you can reasonably recognize the source. The plundering has to be blatant though. There's a lot of samplepocketing, parroting, plagiarism and tune thievery going on these days which is not what we're doing.
Plunderphonics is related to but distinct from sampling used in genres such as hip-hop.
Process music is music that arises from a process. It may make that process audible to the listener, or the process may be concealed.
is an American composer who, along with La Monte Young, Terry Riley, and Philip Glass, pioneered minimal music in the mid to late 1960s
It's Gonna Rain is a minimalist musical composition for magnetic tape written by Steve Reich in 1965. It lasts approximately 17 minutes and 50 seconds. It was Reich's first major work and a landmark in minimalism and process music.
La Monte Young
La Monte Thornton Young (born October 14, 1935) is an American avant-garde composer, musician, and artist generally recognized as the first minimalist composer. He was also tied to the Fluxus ( see above ).
and sonic meditations
a good text to read http://www.osborne-conant.org/oliveros.htm
Teach yourslef to fly score taken from Sonic Meditations
is an American composer of experimental music and sound installations that explore acoustic phenomena and auditory perception.
Much of his work is influenced by science and explores the physical properties of sound itself: resonance of spaces, phase interference between closely tuned pitches, and the transmission of sound through physical media.
I am sitting in a room
Synthesised sound and Daphne Oram a pioneer into one of the earliest form of sound synthesis
When a fluctuating electric current flows through the coil (orange), it becomes a temporary electromagnet, attracted and repelled by the permanent magnet (blue/red). As the coil moves, it moves the cone (gray) back and forth, pumping sound waves into the air (light blue)