For Radio Transceiver

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Regenerative Feedback in the Medium of Radio: Study 1.0 (FM) for Radio Transceiver

Matthew Burtner

ABSTRACT

The author discusses he Studies for Radio Transceiver (2001), pre- lowing the production of an inde- compositional applications of T feedback in the medium of radio sented here, join a tradition of creatively repurposing audio pendent oscillation, a process he as a means of exploring the tools in order to explore the nature of media. A rich body of called “regeneration” [1]. Arm- nature of transmission and compositions using radio signals has been created, including strong’s circuit describes regenera- reception. His Studies for Radio John Cage’s Imaginary Landscape No. 4 (1951) for 12 radio re- tion of the electromagnetic waves, Transceiver are presented here along with a detailed discussion ceivers; Karlheinz Stockhausen’s Hymnen (1965–1967) and or “feedback,” as a means of ampli- of Study 1.0 (FM). This composi- Kurzwellen (1967), which used shortwave radio signals; and on- fying the signal until it creates its tion juxtaposes the historical going projects by musicians such as Holger Czukay and Robin own continuously oscillating elec- and technical use of feedback in Rimbaud (a.k.a. Scanner). These works notably concentrate tromagnetic signal. Figure 1 shows radio with audio signal recur- on the reception of existing radio signals, focusing on col- a photograph of the inside of an sion. Regenerative feedback is used to redefine the composi- lecting preexisting transmissions and in many cases juxtapos- Armstrong regenerative super- tional capabilities of the ing and layering simultaneous unrelated and randomly heterodyne receiver of 1917 [2]. medium. occurring signals. In 1933 Armstrong made an- The Studies for Radio Transceiver expand on this work by ex- other contribution to the technol- amining the nature of radio transmission itself, the music ogy of radio, creating the first being a byproduct of both the transmission and reception of working demonstration of FM. The FM transceiver increased an audio signal. In particular, the first in the series, Study 1.0 the dynamic stability (and therefore the range) of the trans- (FM), considers the broadcast and reception of an FM radio mitted signal by modulating its frequency rather than its am- system’s self-noise; regenerative feedback is used here to re- plitude. Armstrong began making regular FM broadcasts from define the compositional capabilities of the technology. the top of the Empire State Building until he was forced to move out of New York City [3]. By redefining a transmission medium as an instrument, the TRANSMISSION/REGENERATION composer may seek expression as the actualization of the The notion of information transmission is critical in the canon medium itself. A medium such as radio, meant to capture and of 20th-century audio technologies. As an undergraduate at repeat human expression, brings with it the implication that Columbia University, Edwin Armstrong studied Lee De For- a message is contained in the signal. However, despite the fun- est’s radio tubes, which had been designed for the Marconi damental connection of radio transmission technology to feed- radio company. He altered the De Forest tube by feeding high back, this presumptively transmitted content is subverted if levels of electromagnetic waves back through the tube and al- the signal is recursively fed back into the system. Signal regeneration allows the nature of the medium to take on pri- mary importance, asserting itself into the audio content of the Fig. 1. Inside view of the Edwin Armstrong Superheterodyne Re- message. Thus, feedback points to the conception of the ceiver of 1917. Armstrong’s modifications of Lee De Forest’s tube are the basis for the technology used to compose the Studies for medium as an instrument, the process of signal generation be- Radio Transceiver. The three-element tube allowed for the amplifica- coming the signal itself. tion of signals and production of radio signals. (Photo © Matthew Burtner) THE STUDIES FOR RADIO TRANSCEIVER Study 1.0 (FM) is the first in a larger series of Studies for Radio Transceiver, part of the World Noise Radio Project (WNRP). This project questions the nature of the radio medium in general and particularly the role it plays in forming the content of a musical signal. It explores the alteration of sonic content as it is passed through a medium to a receiver. The project was first defined in a lecture on the question of content and medium presented as a remote FM transmission to Brian Ferneyhough’s composition seminar at Stanford Uni-

Matthew Burtner (composer, educator), Composition and Computer Music, Virginia Center for Computer Music, McIntire Department of Music, University of Virginia, Charlottesville, VA 22903, U.S.A. E-mail: [email protected].

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versity [4]. In the conceptual art piece, points on a frequency spectrum become consequently polluted with powerful sig- WNRP, the medium of radio itself pro- ideological bridges over which we pass nal transmissions. Collecting unpolluted vides musical content. Accordingly, com- into an unoccupied, peaceful world. radio signals became increasingly prob- In remote parts of the North, scan- lematic with WNRP. Therefore a new In- positional content before transmission is ning the FM dial reveals that no human ternet radio station was formed that only minimized in order to focus on the prop- signals are being broadcast. The feeling broadcasts noise. Internet radio, unlike erties of the medium through broadcast provoked is one of aloneness, isolation, its analog, wireless companion, is suspi- and reception. and vast spaces. By contrast, scanning ciously lacking in random noise. Degra- the FM dial in populated parts of the dation of quality is introduced as a The Studies for Radio Transceiver are best world creates a feeling of acoustic claus- byproduct of file encoding, but the described by the score itself, which is a trophobia. This piece attempts to use the medium lacks the inherent chaotic series of text instructions for realizing the real time noise net as a means of recon- acoustic properties that characterize the pieces. The performable pieces of the structing a world of emptiness. signal of analog radio. A version of the group were first presented on 4 October Study 1.2b (net). Once the net is estab- Internet World Noise Radio Project was lished, the radio transmitter transmits a first broadcast (since September 2001) 2001 as part of the Strictly Ballroom series’ silent signal, and the performer freely al- at http://www.live365.com/stations/ “Mechanical Music” concert at CCRMA, ters the circuitry and broadcast fre- 278291. Stanford University. Each study exploits quency. The frequency modulation takes a particular aspect of transmission and over each receiver in a different way, and a variety of radio sounds can be pro- STUDY 1.0 (FM) reception through the FM medium. duced by altering the capacitance and FOR RADIO TRANSCEIVER Studies for Radio Transceiver antenna length of the transmitter, and by Matthew Burtner, 2001 moving around the concert space. The Study 1.0 (FM) for Radio Transceiver refers These pieces can be performed in any “net” is heard as coming to life, each to Armstrong’s work and the origins of order, manner. node evolving into a voice of its own, gen- frequency modulation by using feedback Study 1.0 (FM). Transmit a silent sig- erating a polyphony of radio noises. to amplify the signal properties of FM nal. Receive the signal and feed the line Study 1.3 (drift). Broadcast some rec- outputs of the receiver back into the ognizable music over the FM transmitter. and of a specific transmission/reception transmitter. A loop is created in which As the audience listens to the transmis- circuit. The characteristics of the the listener hears the compounding of sion, the transmitter is gradually moved medium are revealed in the noise-to- the inherent noise generated in the pro- away from the receiver. The music at first pitch transformation brought about by cess of transference. The growth of the is clear but gradually becomes noisier. systemic noise moves from the periphery On the fishing boats in Alaska, as the the feedback system. of the music, a byproduct of the media, boat moved into a storm or down the Study 1.0 (FM) uses gain control of the to the central focus of the musical mate- coast, away from the transmitter, the sig- feedback into the circuit as a means of rial. We hear the resonance of the FM nal would gradually disappear. I re- slowly revealing the properties of the sys- band grow from noise, the intoning of member sitting close to the speaker, tem. A radio transmitter transmits an the medium. trying to catch the fading notes of a piece Study 1.1 (diffusion). Transmit a musi- of music as it vanished without a trace cal signal in a concert setting. The au- into noise. Poor audio reception creates dience provides the sound system for the a sense of intimacy, like watching the last Fig. 2. Electronics setup for Study 1.0 (FM) concert by tuning in on a variety of re- flames recede into embers in the fire- showing the signal path. (© Matthew Burt- ceivers to the specified frequency. The place. The impoverished quality and sub- ner) number, quality, and spatial positioning versive noises on old records create a of the speakers create the sounding re- feeling of nostalgia. Similarly, any fa- sult, a result that, although fixed in trans- miliar medium that once served as a con- mission, will be diffused differently for duit for artistic perception evokes a sense each performance. The music in this of nostalgia. But nostalgia does not ad- context is a fragile signal that is “discov- equately express what is happening per- ered” by the audience in real time as it is ceptually. This nostalgia is not simply a projected through the imperfect temporal longing, but also a material medium. A bond is formed between the one. It is a feeling of closeness, depth, music and the listener’s sense of discov- and intimacy to the work of art, brought ery and need to protect this fragile about through the close listening expe- sound. The FM noise floor creates a rience created by the media. sense that at any moment the signal Study 1.4a (WNRP). The World Noise could vanish into the noise forever. Radio Project started as a series of site- Study 1.2a (net). Several performers, specific “radioscape” miniatures, col- each playing a different radio receiver, lected from different frequency are spaced throughout the hall. Each spectrums from different locations performer is assigned a range of the FM around the world. My hope was to doc- spectrum. They turn on the receiver and ument the worldwide existence of a begin tuning it, within their range, to a “noise radio,” common to all people and frequency that falls on an unoccupied places. In the context of WNRP, the band of the FM spectrum. Once each radio noise became an analogy for peace, performer has found an uncorrupted unity and equality. Theoretically, white band, the noise web is established and noise (containing all frequencies at held. equal amplitude) forms a solid, non- The activity seeks to uncover the “in- acoustically partisan block of sound out tact” fragments of a fractured FM band of which any signal could be potentially (88–108 MHz). By focusing on the un- carved. White noise contains, in theory, used parts of the bandwidth, a concep- all possible musics, expressions and lan- tual bridge is created between these guages. By forming geographical, cross- cracks. A philosophical process of cultural acoustic signifiers through the human erasure is attempted. The net radio band, an acoustic worldwide unity strives towards emptiness. And thus the is created. viewer perceives a negation of the hap- Study 1.4b (WNRP.net). Unlike the out- hazard distribution of sonic intentional- back of Alaska, most populous areas are ities across the airwaves. These isolated overcrowded and their radio bands are

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sends the FM transmitter carrier signal to an antenna socket. A long copper wire is soldered to the antenna socket pro- truding from the top of the circuit board (Fig. 3). The sounding result is a gradual move from noise to a gentle intonation of a resonant frequency of the complete circuit. The performer changes the gain slowly, listening for feedback building in the system and making the slowest possible transition from noise to pitch. In this way, an attempt is made to focus the listener’s perception of the noise characteristics of the FM medium and upon the properties of this particular circuit. The transmitter circuit board is left open so that the performer can impro- vise by interacting with the circuitry dur- ing performances of the Studies. As the performer reconﬁgures the circuitry, partially shorting components in different combinations or changing the antenna length, unpredictable changes in the output signal can be produced.

CONCLUSION/RECURSION Figure 4 shows a sonogram of a performance of Study 1.0 (FM). The image ex- Fig. 3. The FM10A radio transmitter circuit board used in the ﬁrst performances of the poses the simplicity of the musical Studies for Radio Transceiver, 2001. (Photo © Matthew Burtner) structure, almost iconically symbolic in form. Over the course of approximately empty signal on a chosen band of the FM decreasing it. The carrier signal of the 3 minutes, a harmonic tone of around spectrum. A receiver is tuned to the same transmitter inductor coil (IC) is set by ad- 1,033 Hz gradually surfaces, becomes sat- band and the output is routed back into justing the resonant circuit formed by the urated into noise, returns to the pitched the transmitter. By placing a gain control combination of a capacitor that sets the sound and then disappears into noise as in between the transmitter and receiver, general transmission band and a shielded the feedback is modulated. the amount of feedback signal can be IC, which tunes the transmitter within Through this feedback process, the na- controlled by a performer (Fig. 2). that larger range. This is also set in ad- ture of the transmission itself is explored. Any standard FM radio transmitter and vance of performance, the transmitter Unlike the radio compositions of Cage receiver will work; performances to date and receiver being tuned to the same, or Scanner, the Studies for Radio Trans- have used an 18-pin FM stereo-transmit- clear frequency. Power to the transmitter ceiver do not attempt to examine the so- ter integrated circuit by Ramsey Elec- IC and to a Negative-Positive-Negative ciopolitical convergence of radio signals. tronics with a variety of off-the-shelf Very High Frequency (NPN VHF) tran- Rather, they circumvent human expres- receivers. Composition of the piece fo- sistor is regulated at 2.1 volts DC by three sion in these bandwidths in order to con- cused essentially on building the FM glass-bead diodes. The radio frequency struct a unity aside from human transmitter circuit. The circuit acts as a (RF) output from the VHF transistor expression. The pieces enter a territory homemade instrument or a type of score deﬁning the path of electricity through itself. Performance of the piece is a grad- Fig. 4. Sonogram of the Study 1.0 (FM) showing the formal spectrographic evolution over the ual revealing of the properties of this cir- 3-minute duration of the piece. (© Matthew Burtner) cuit. The slow change of gain control to the circuit requires a type of concentra- tion that focuses the performer’s atten- tion towards and into the circuitry of the instrument. Two potentiometers allow adjustment of each channel of the input signal. The performer sets these carefully prior to performance to avoid distortion of the feedback signal. In performance, the mu- sician controls the gain of the input to the transmitter with an external gain control, very gradually increasing and then

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crowded with signal intentionalities problematizing current models for in- sical Signal—A Case Study, FM transmission presented and then avoid those signals entirely. Spe- formation transference. to Brian Ferneyhough’s Composition Seminar, Stan- ford University, CA, 2001. cific messages are avoided in favor of In “La Radia,” F.T. Marinetti and Pino message potentialities, those found in the Masnata wrote that radio “shall be ...the 5. F.T. Marinetti and Pino Masnata, “La Radia,” in Douglas Kahn and Gregory Whitehead, eds., Wire- frequency-rich field of noise, out of synthesis of infinite simultaneous ac- less Imagination: Sound, Radio and the Avant-Garde, which any potential signal could be tions” [5]. In the Studies, it is through re- Stephen Sartarelli, trans. (Cambridge, MA: MIT Press, 1996); reprinted from Gazzetta del Popolo (Oc- shaped. The closeness of human trans- cursion and noise that the medium tober 1933). missions in the FM band creates a signal references this notion of infinite simul- 6. J. Milutis, “Radiophonic Ontologies and the Avant- crisis that generates the meaning of these taneity. Feedback, so closely tied to the garde,” in Allen S. Weiss, ed., Experimental Sound and pieces. They would be quite different technology of radio, exposes a poten- Radio (Cambridge, MA: MIT Press, 2001). pieces if the FM band were completely tiality of the medium as a voice of its own. empty of human transmission. Antonin Artaud’s statement that “all Bibliography Additionally, unlike the radio pieces of words, once spoken, are dead” [6] is con- Nahin, P.J. The Science of Radio (Woodbury, MN: Stockhausen or Czukay, the Studies do not fronted by the notion of recursion. The American Institute of Physics, 1996). attempt to discover new sounds arising signal, once spoken, is not spoken at all; Rutledge, David B. The Electronics of Radio (Cam- from random fluctuations of radio sig- only through regeneration does the bridge, U.K.: Cambridge Univ. Press, 1996). nals. Rather, these pieces point to the medium itself speak. conceptual nature of media and the way signals are transmitted wirelessly across References Manuscript received 1 May 2003. space. The conceptual aspects of trans- 1. T.S.W. Lewis, Empire of the Air: The Men Who Made Composer and sound artist Matthew Burtner mission, here metaphorically embodied Radio (New York: HarperCollins, 1991). in FM, are more important than any re- teaches composition and computer music at 2. “The Information Age,” Smithsonian American the University of Virginia, where he is associ- sulting sounds. The negative space of History Museum exhibit, Smithsonian, Washington, ate director of the Virginia Center for Com- sound (I do not mean “silence”) is the D.C., 2003. puter Music. A native of Alaska, he creates material of this music. As such, the Stud- 3. L. Lessing, Man of High Fidelity: Edwin Howard Arm- music that incorporates a wide range of tech- ies evoke potentially vast and empty strong (New York: Bantam Books, 1969). nologies, exploring ecoacoustic processes and spaces. They struggle to keep the means 4. M. Burtner, WNRP (World Noise Radio Project): On extended polymetric and noise-based musical of communication open in these spaces, the Nature of Transmission and Its Role in Shaping Mu- systems.

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