The concept xxx
A. M./F.M Sine Wave is the title of a series of free field Sound Constructs. The term free field Sound Construct refers to the three-dimensional ordering of atmospheric space by means of sound transmission where there are no reflective surfaces and therefore no reverberant fields.
These pieces are produced by employing an amplitude modulated ( A.M.) Radio receiver, a frequency modulated radio receiver (F.M.) And a sine wave generator.
Signals from these instruments are fed individually to modifiers (such as ring modulators and filters), then two separate amplifier channels and finally two separate speakers which are arranged in a predetermined configurations (see block diagram – Page 2). The speakers, in turn, convert these electrical signals into sound waves.
These sound transmissions set volumes of air in motion in variance with sound pressure level, frequency, waveforms, wavefronts and apertures. Here is a simple example of air volume variance related to frequency: s very high-pitched sound of 17,600 cps (See reference chart – Page 4) emanating from a 15 inch cone speaker will, because of the relatively large aperture, cause a very narrow beam of air to be set in motion diverging at a 2.6° angle. Walking around and through different areas of the sound beam the auditory explorer will perceive this three-dimensional beaming effect. If, however, a low pitch sound of 518 cps (See reference chart- page 5) should emanate from the same 15 inch aperture at the same sound pressure level, the area of air being set in motion will be wider-diverging at about and 86.7° beaming angle. The lower the pitch (assuming the same size aperture), the wider will be the beam. The width of the beam will increase in size as the pitch gets lower, widening to the point where the sound is so dispersed that there is no discernible beam pattern.
Aperture size also affects the beaming a fact. If a frequency of 1200 cps is applied to a 3 1/2 inch aperture, the beam angle will be about 160° (see reference chart-page 4). If the same signal is applied to an aperture eight inches in diameter, the beam will diverge at a 70.1° angle (see reference chart-page 5).
The relation of sound pressure level variance of a sound to the three-dimensional manipulation of air volume is readily apparent in the decline of loudness as one walks away from a sound source in an open area. This is also obvious when adjusting the volume control on a radio or television.
In a closed field situation, such as a small art gallery room, the acoustical peculiarities must be taken into consideration in the design and execution of a work so as to not confused or, in the case of a very live (highly reverberant) room, totally obliterate the desire degree of construct- element separation.
In order to further clarify the concept of sound constructs, the artist shall discuss A.M./F. M./Sine wave number one, the first in a series of works employing similar sound sources. In the section following this essay, a more detail description of that work will be presented along with some of the variations in the series.
A.M./F. M./Sine Wave number one can be compared in many ways to the Max Neuhaus house piece Times Square. Because of the comparisons between the two pieces and also because of the accessibility of the Neuhaus piece to this artist‘s New York audience, a short discourse comparing some elements are the two works follows. It is hoped that a demonstration of the similarities and differences between A. M./F.M./Sine Wave number one and Times Square will effectively serve to illustrate and clarify some of the formal anesthetic considerations being dealt with by this artist and the design and realization of sound constructs.
It must be noted that the following appraisal of Times Square is this artist’s interpretation of the work in relation to his own theories regarding Sound Constructs does not necessarily reflect the artistic intentionsof Max Neuhaus
Times Square is a complex amplified electronic signal generated from a large speaker. This speaker was installed by Max Neuhaus under a subway ventilation grate in a pay pedestrian island at Seventh Avenue, between 45th and 46th St. in New York City.
The Neuhaus piece includes the environmental sounds (people sounds, traffic sounds, etc..) as well as the electronic sounds generated by the artist. The sound sources of A.M./F. M./Sine Wave are also comprised of environmentally derived sound sources (A.M. and F. M. Radio programming) and an artist generated sound source (Sine Wave). Neuhaus employees at least one static* sound source as part of the electronically generated complex waveform. And a similar manner A. M./ F. M./ Sine Wave number one employees the sine wave to statically modulate an air volume. The artist classifies this static air volume modulation as audiostasis.
*There seems to be an amplitude modulation occurring at the lowest frequency of the electronically generator sauce, that’s qualify that portion of the seagull as kinetic.
It is important to understand at this point that the content of the programs being sounded over the two speakers in A.M./F. M./Sine Wave number one is not relevant to the understanding of the piece. The relevant information is the manner in which the varying waveforms, at constantly changing amplitudes, modulate the atmosphere in the same way that the street sounds of Times Square modulate their respective air volumes. The artist classifies this change your volume modulation as Audiokinesis.
The artist classifies both times square and eight. A.M./F. M./Sine Wave number one as examples of audiosynapsis end the joining together of static and kinetic sound phenomena in the same timeframe
In order to better articulate the nature of sound contracts as the three-dimensional ordering of atmospheric space by means of mechanical disturbance, the artist found it necessary to devise n additional classification system of sound sound constructs based upon the three basic sound source configurations available in reference to the sound construct.*
*The physical area designated by the artist and/or the perceiver as the artwork.
The three basic categories are:
1. External Orignation-All sound sources are located at or outside the boundaries of the sound construct.
2. Internal Origination – all sound sources are located along the vertical axis at some point within the sound construct.
3. multiplex originate –also sources are located at various points within the sound construct. In addition, sound sources may also be located at or beyond the boundaries of the sound construct.
In light of these three classifications the differences between Times Square and A M./F.M./Sine wave number one become readily apparent: the horizontal dimensions of the new sound construct shall be understood as the perimeter of the pedestrian island upon which the grid is located. The vertical dimension shall be understood as the height of the individual explorer. W shall incorporate it into our conception of the work the electronic sound source originating from beneath the grid as well as the auditory information emanating from beyond the boundaries of the construct (the sounds of cars, buses, airplanes, subway trains, etc.). We shall further incorporate the newer sound sources within the sound construct (pedestrians walking and talking, pigeons flapping their wings and cooing, etc.). With this information understood Times Square can be classified as a multiplex origination sound construct.
A.M./F.M./Sine wave number one, on the other hand, is comprised only of sound sources located at the boundary of the sound construct. The sounds of people walking and talking within the boundaries of the piece will, in this case, be regarded as noise and hence extraneous to the work. This parameter of the work is established by posting exploration instructions in the immediate vicinity of the work. With this information understood, A.M./F. M./Sine wave number one can be classified as an external originating sound construct.
The perception of audiokinesis in both of these works may be hindered by the apparent linear progression of sound vents. To experience a sound construct in this manner is to perceive it as a work of musical art – Which it is not.
Audiostasis is more easily perceptible because discreet sound events are not present. Walking from one area to another within the construct does, however, constitute a real-time sound experience which might also be construed as a musical one.
It is essential, therefore, to stress the fact that the understanding of sound constructs hinges entirely on the explorers’s perceiving modulated air volumes-not his or her listening to linear progression of sound events.
The Work
The piece shown on the following two pages includes an experimental super directive speaker array. This configuration is based on a design used in experiments at Bell laboratories in the 1950s. The design requires five speakers to be alternately phased and positioned1/4 wavelengths apart. The phasing in positioning focuses the the sound beam into a much tighter pattern then when the speakers are all activated in phase.
The artist based his array on the limited information available in Winston E. Kock’s seeing sound published by Wiley-Interscience. The figures regarding beam width dimensions of the super-directive array accompanying the photograph of the A M./F. M./Sine wave number one are approximate – pending more accurate measurements of the arrays output patterns.
At this time a search for more information regarding multi-speaker super-directivity experimentation is also being conducted by the artist.
Please note: a band pass filter was inserted between the ring modulator and the amplifier of A.M./F. M./Sine wave number one in order to more accurately control the sound bean pattern of the 7 inch speaker. (See block diagram-page two).
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