From beats to bodies
As in the work of La Monte Young, binaural beat audio positions its listener to complete the work psychoacoustically. The beat does not exist external to its listener, but only in the passage between the body and audio object. While dichotic listening avoids the spatial play of La Monte Young — in the tight coupling of speaker and ear, there is no space that the audio can occupy other than the skull — binaural beat audio and its psychoacoustic synthesis are intimately tied with temporal perception; thus, in designing these audio works, the affective subject is always and necessarily presupposed. Crystallized within the media object is the supposed psychoacoustic body and the affective capacities of that body to hear between the speakers. To invoke the language of Wolfgang Ernst (2013), binaural beat audio is a “time-critical” media, where “exact timing and the temporal momentum is ‘decisive’ for the processes to take place and succeed at all.” Without its particular play of time, there is no binaural beating. Phenomenologically, to hear the binaural beat is to take part in a particular working of time on a microscale. Digging deeper into how the psychoacoustic perception of these microtemporalities is appropriated in the design of binaural beat audio requires a consideration of the interplay between the physics of sound and the psychoacoustic, phenomenological subject.
Though Ernst is characterizing technological media, sound perception, apart from any reproduction technology, is fundamentally time critical. As Nuno Fonseca (2014) notes, not only do sounds necessarily “occur in time,” but they also have duration, either instant or extended: sounds always start in time, and sounds always cease in time. Moreover, the basic detection of sound, whether sound is heard or not heard, is contingent on temporal factors. As Fonseca points, sounds that last less than 40 ms will likely be inaudible. Beyond detection, sound localization is largely temporal — sounds are localized in space based on interaural time differences, i.e., the time difference between a sound reaching one ear and then the other. The distance of a source, as well as the relative speed and direction of a source’s movement, can always be ascertained via sonic clues, such as amplitude levels varying over time. Even environmental data can be garnered from time differences — a sound playing in a cathedral sounds different than the same sound playing in a carpeted room due partially to differences in room acoustics and reverberation time, i.e., the buildup of sound reflections and the time those reflections take to decay in the space. Thus, as Aden Evens (2005: 31) writes in his thorough phenomenology of sonic perception, “just as sound compresses and rarefies the air, so too it compresses and stretches time.” The compression and rarefaction, as it occurs in time, refers to frequency. A sound’s “wavelength” is simply the distance from one compression to the next, and a sound’s frequency is inversely related to wavelength — the shorter wavelength, the higher the pitch. It is no wonder that prior to the “Hz,” the standard measure of frequency was Cycles per Second (CPS), where a “cycle” refers to a single period of compression and rarefaction. Frequency is merely the rate with which air is vibrated as a series of compressions and rarefactions. Thus, a 440 Hz tone is 440 compression and rarefaction series every second.
Just as frequency is time critical, so too is timbre. Timbre, the “character” or “quality” of a sound, results from the distribution of harmonics in a tone. Thus, the sound of a pure sine wave (the “null” timbre, as Evens calls it) differs from the sound of, for example, a clarinet, largely due to the emphasis of different harmonics. While with a simple sine wave the listener only hears a single fundamental frequency, with a clarinet tone the fundamental, as well as intervals of an emphasized fifth and major third, can be heard, though of lesser amplitude. This is time critical most obviously in that harmonics have frequency, and frequency is time critical. But, beyond the distribution of frequency, timbre results from the “envelope” of a sound, i.e., length of its onset, its sustain, and its decay, and how these factors vary in time, where different harmonics sustain and decay at differing rates — all through the dimension of time.
In the interplay between the physics of sound and the physiology and psychoacoustics of perception, time is the linking factor. Forming an “unstable tangle,” the various temporalities — micro- of frequency and timbre, macro- of duration and form — mix and meld in the translation from environmental phenomena, from vibration in the air, to the perception of sound (Evens 2005: 58). Thus, returning to the binaural beat, while two pure sine waves occur in the measurable world, the beat only occurs internally, in translation, in the passage from object to body. Never passive, Evens notes, perception is always affective: “the body behaves itself, acting on and reacting to its environment” (41). As is emphasized in the work of La Monte Young, perception is always and only creative, and, to that extent, per Fonseca (2014), “a sound,” as something that occurs out there and heard in here, “is somewhat a perceptual fiction.” Sound, as it occurs in the environment, is constant and dense. As the body attempts to make sense of it, detail is reduced, complexity “decomposed” in the myriad processes of auditory perception. One does not merely “hear” the sympathetic resonance of the tympanic membrane, but, rather, hears the resultant cognitive functions that allow the body to “effectively engage with the environment” — effectively and affectively. Sound in the environment is thus not merely translated as in the energy transfer from a vibrating microphone diaphragm to a vibrating speaker cone, but entirely transmuted: converted from vibration in the world to vibrating, non-cognitive, intensity in the body to neural-electrical impulse. Moreover, in the perception of the binaural beat, transmutation occurs on a different temporal scale — from microtemporal frequency to temporally normative rhythm. From the frequency difference between two tones, the psychoacoustic third tone envelopes the combination in an audibly beating pulse that varies along with the frequency of the initial tones. Temporally situated in this manner, sound is never static, but, much like the perceiving body, always becoming, always in action, between the body and stimulus. It is not just the mind that listens, as Adel Wang Jing (2012) writes, but the entire body is implicated in the process — unfixed, unstable, in constant flux and embedded in an evolving context. As an affective subject, presupposed and positioned by the materialities and temporalities of binaural beat audio, the listener listens in joint effort with the material itself, in “relations of movement and rest with [the] sounding materials” (Jing 2012). To use the audio-relevant language of Brian Massumi (2002), the body is a transducer, bringing together disparate materialities — from the transistors in the sine oscillator to the speaker cones of the headphones to the tympanic membrane and the cognitive functions of auditory perception — converting environmental vibration to sound actively, converting external material difference to internal immaterial rhythm. Intentional design around known psychoacoustic phenomena, the time-criticality of sonic perception, and the presumed affective capacities of listening subjects mark the passage from external stimulus to affective intensity, from a real outside to a virtual inside.
With the above understood as an accepted model of auditory reception, it does not seem an illogical jump to assume that just as sound incites neural-electrical impulses in the brain, it similarly might incite brainwaves in sympathetic resonance via the autonomic mechanics of entrainment. Such marketing claims position the psychoacoustic subject — where auditory reception is a creative, yet not necessarily cognitive, act — as collaborating with the sound source and environment in the perception of sound. The discourse of entrainment promises to extend the effects of sound throughout the body and makes the binaural beat a catalyzing force in eliciting desired and designed mental states. Emphasizing this design aspect, binaural beat audio, unlike its claimed “analog” drug counterparts, such as LSD, and unlike traditional meditation practices, comes to the market wrapped in claims that it can elicit particular and exact mental states or enact particular effects, depending on the composition of the audio and the brainwaves which it is meant to stimulate. Whereas with LSD and meditation one must simply go where the drug/practice takes one (thus the frequent invocation to “be here now” in both the use of psychedelics and in meditation practices) , the discourse around binaural beat audio, including that which celebrates the precision of its production technology, positions its subject as finely manipulable, able to be entrained sympathetically (with an 80% success rate, per I-Doser.com). Straddling the line, as it does, between science and pseudoscience, medicine and alternative medicine, the discourse of binaural beat audio positions its subject at the intersection of science — via its implicit theories of electroacoustic physics and the psychoacoustic body, as explored at length above — and New Age heterodoxies.
 From Ram Dass’s (1971) Be Here Now, a guide to Hindu spiritualism that found much favor in North America.