When Dogs Bark…
The world I exist in is sonorous, but where dot he sounds come from and how is it that I am able to hear them?
I know that many of the innumerable events taking place result in waves of vibration – differences of pressure which radiate outward through the air from a causative source. I know also that these bands of positive and negative pressure cause disturbances of air-particles which, after a process involving my ears and brain, I am able hear as sound.
It is my ability to hear which allows me to listen, to tune in closely. I sense that this sensitivity to the world is in a way profound, that to hear is to be open to the world, symbolically and literally. Hearing is present for me regardless of where attention is directed, idling in the background. In a manner, hearing could be considered in relation to seeing, in that I hear the world whether or not I want to in the same way that the world appears in my vision regardless of my choosing. Then there is listening, which might be pondered in relation to looking: an active, directed, interested operation seeking for a object or occurrence. I see as I hear, as if almost by accident, and I look as I listen, at or for an object currently at the centre of my attention.
My aural experience of the world began even before brith. From the seclusion of the womb, vibrations from beyond arrived at my infant ears through the fluid in which I floated, imparting a steady stream of sonic information. Indeed, the womb was a loud place filled constantly with muffled reports of outside comings and goings which mingled among the ever-present, rhythmic pulses of my mother’s cardiovascular and respiratory systems. From even before the moment of birth, my hearing has functioned continuously – a complex relational connection to the world beyond my body.
The mechanisms of my hearing, and yours, have developed over the course of human evolution. The business of this short text is to provide a basic description of how vibrations in the world become audible, and to share some thoughts about how our ability to hear and listen reflexively influences experience.[i]
First there is the outer ear:
For an experience of sound to occur, the vibrations from the world are firstly received by my outer ear which is comprised of the pinna (or auricle). My outer ear is the only aspect of a complex system visible from the outside. Its purpose is to direct the world's rumblings inward toward the middle ear. As if funneling a liquid or powder to a small, specific destination, the Helix, antihelix, concha, crus helias, tragus and antitragus orient reports of the world inward.
Then the middle ear:
As vibrations travel from the outer ear down the auditory canal, they cause my tympanic membrane to vibrate, relaying the signal further into the labyrinth of hearing.
This membrane marks the divide between the outer and middle sections of my ear. It is here where the vibrations affect some of my body’s smallest and most specialised bones – the malleaus, incus, and stapes (known also as the hammer, anvil, and stirrup, and collectively as the ossicles). These bones are located in the tympanic cavity which serves to amplify the vibrational signal while also focusing it at the superior oval window which ‘looks’ into my inner ear.
Into the inner ear:
The defining feature of the inner ear is the snail-shaped cochlea, a coiled, fluid filled tube which tapers along its length. The cochlea is bisected by the basilar membrane, a stiff partition separating the discrete sections within the tubular cochlea – the scala media and scala vestibuli from the scala tympani. The thickness and stiffness of this membrane varies along its length causing different sections to resonate at different frequencies just as the strings of a guitar or violin do. The result of this is that different sections respond to different frequencies of vibration, ultimately producing my experience of differing pitches. The intensity of the movement of the basilar membrane is also responsible for my experience of differing intensities of sound.
Thousands of highly specialised hair cells are distributed along the top edge of this membranous labyrinth, at the tip of each of which are stereocilla, cell modifications which allow the conversion of mechanical energy into electrical impulse. As the endolymph fluid inside my cochlea ripples in response to the amplified vibrations of the outside world, the basilar membrane responds in a wave-like manner, rising and falling in relation to the vibration.
As this chain of cause and effect continues within my inner ear, the tiny hair cells atop the basilar membrane, riding the rippling waves within the cochlea, interact with the organ of Corti, the receptor organ of human hearing which is located within the cochlea between the vestibular and tympanic ducts.
Along the length of the organ of Corti are an extremely high concentration of yet more hair cells each tipped with ion-gated, pore-like structures. When triggered (or tickled) by the hair cells atop the neighboring basilar membrane, these gated structures open allowing the release of the neurotransmitter glutamate.
Then, finally, translation:
It is at this point where the transduction of external, vibrational energy into the electrical impulses I experience as sound occurs. The influx of glutamate into the organ of Corti generates a series of graded potentials which give rise to electrical signals. These signals are rapid, and travel quickly from the organ of Corti along the cochlear nerve, up the auditory pathway, along neuronal highways to my temporal lobe where the auditory cortex is located. Upon reaching the auditory cortex the impulses are decoded, and my experience of sound ultimately takes place.
The experience of hearing and listening is an innate aspect of my experience of life.
That I am able to hear is the result of a complicated process involving vibrations in the world and the mechanisms of my hearing, i.e. my outer, middle and inner ear, which is decoded within the auditory cortex of my brain. While I am in a manner correct in attributing the sound I hear to a dog’s barking, the experience of sound is equally also the product of a complex process of transmission, amplification, transduction and translation. To answer to the question “what are you listening to”, then, is a complex endeavor, however several things do appear clear.
1) The waves of vibration which result from events in the world are distinct from the mixture of electrical and neuro-chemical stimuli caused by the release of glutamate in the inner ear, traveling as electrical impulses along my auditory nerve to my auditory cortex where they are decoded as sound.
2) The worldly source of a vibration is simultaneously removed from and the genesis of my experience of sound.
3) That which I experience as sound is as much a product of my ears and brain as it is a thing in the world beyond my body.
Nonetheless, to hear and listen are profoundly relational, and intensely corporeal experiences through which the world takes on meaning. As such, my life as a listening, hearing being is entwined with the facts of how I hear (how I hear both in the sense of how my hearing happens and how I behave as hearing being).
From hearing to listening:
My initial response to a sound is driven by an inherited imperative to survive. This compels an impulse to identify whether or not the worldly origin of a sound poses a threat. This impulse can grab my attention causing a sound to move from the domain of hearing into that of listening.
From within the soup of audible vibration, an unexpected sound can take command, imposing itself in such a way that I immediately and without choosing find myself attending acutely to its source. I am fortunate in that, the most part, I experience a safe world in which I am unlikely to be hurt, but nonetheless, this compulsion can still achieve the tier-hopping effect once essential to the survival of my forebears, shocking me to attention. Due in part to the evolutionary relationship between surprise and immediate danger, such unexpected sounds seize me and my attention forcing a listening experience, if only for a fleeting moment. The fleeting jolt which gives rise to this kind of arrested listening experience is at times unpleasant – I cannot help but pay attention to sounds which arrive in this way. That said, I more often arrive at a state of listening following an active choice to remain with a sound, eschewing others with focused intent.
To remain with a sound, considering it with care or curiosity, is to stray from the mere sensitivity of hearing into the concentrated, relational, always active and intentional domain of listening. It is here where deeply subjective (and potentially profound) aural experiences take place; where an annoying sound frustrates me and a pleasant sound brings delight. As I listen it is almost as if the object of my attention migrates from its physical source in the world to the border between my self and that beyond.
In listening intently, I meet sound halfway:
To listen is to engage a sound, to allow it to take hold, to be engrossed in a uniting of sensitive and and consciousness.
Aural evolution has resulted in some sounds being privileged over others. Over the course of human evolution our ability to hear has become attuned to sounds we (collectively and over time) have benefitted from hearing. Through the concentration of hair cells on my basilar membrane, I am more or less sensitive to sounds possessing particular qualities of pitch and intensity. At a basic level, this evolutionary ‘tuning’ of my aural system is related to the probability that hearing a certain sound will be useful. In addition to being more sensitive to certain sounds (for example those within the band of frequency shared by the human voice), my brain also assists by filtering from the soundscape what it assumes I am merely distracted by. In daily life this hardwired aural focalisation, known as ‘the cocktail party effect’, allows for easier human communication in chaotic sonic-environments such busy streets.
Listening to space:
An aspect of aural tuning I have been particularly interested by in recent years is our ability to aurally experience space itself. This essential wonder of hearing is known as auditory spatial awareness and gives rise to subtle sensations related to the scale and nature of the space around us. Beyond the fact that I am, in a manner of speaking, able to hear something such as space, which in and of itself does not make sound, this sense plays a constant role in day-to-day life, contributing to that ineffable ‘feeling’ of being in space.[ii] Upon first learning of this perceptual phenomena, I became fascinated. To my thinking, the concept of auditory spatial awareness constituted a link between human perceptual potential, the evolutionary and social history of our engagement with the world, and the historical development of musical forms.
I found myself engrossed, and began reflecting deeply on the manner in which certain acoustic qualities become conducive to particular behaviors or atmospheres, and how what may be desirable in one space may not be for the next, suspecting, as I continue to, that there is a degree of reflexivity at play. I took note of how in living rooms and bedrooms we create (consciously or by convention) an intimate, ‘close’ acoustic environment through the addition of soft-furnishings and heavy curtains (in older times, this effect was achieved with the hanging of tapestries), whereas in other spaces, such as those of ceremony or worship, a long reverberation time is desirable, allowing the exaggerated blending of voices while giving the space itself a hallowed ambience. In recent decades studies of the development and history of aural-architectural practiced have emerged, further fueling my growing obsession.
Ancient origins of aural-architecture:
In modern times, the practice of architecture affords vision precedence over hearing, however there was a time when the balance of sensual priority was more even. With respect to the earliest examples of aural-architectural practice, it has been proposed by the acoustic archaeologist, Steven Waller, that “echoing locations such as cave sand canyons would have […] been considered sacred, and were decorated with the images evoked upon hearing the echoes. For example, […] echoes of percussion noises such as clapping can mimic the sound of hoof beats, and hoofed animals are a frequent rock art theme. Voices appear to emanate from rock surfaces where beings are depicted, as if the images are speaking.”[iii] For me, this is nothing short of fascinating.
The sophistication of aural-architecture is palpable in early buildings, designed prior to the hegemonic ascendency of vision by architects tailoring spaces to the needs of their employer with open ears. This necessarily included both the visual and acoustic properties conducive to the activity the space was to enclose.
A prime example of this can be observed in the history of spaces of worship, where aural and visual considerations existed on equal footing. For example, it is accepted the hollowed cavities within the walls of the Ali Qapu Palace in Iran are as much for acoustic benefit as they are for visual splendor, in effect creating resonating chambers similar to those of an acoustic guitar or violin within the structure of the space itself. The same acoustic thinking is also evident in to Christian churches and cathedrals, wherein the liturgical intonations of preachers resonant a length as a result of the materials and design employed in the creation of the space itself. Over time, the acoustic quality of such significant spaces began to influence the trajectory of pursuits beyond their initial purpose, such as music. A quote from Barry Blesser and Linda-Ruth Salter is instructive in this regard:
“Though at first an incidental outcome of the scale (and associated splendor) desired by congregations, the lengthy reverberation time of cathedrals, historically functioning as sites for both musical performance and religious worship, promptly became instrumental in its own right, firstly for the way it accentuated and emboldened spoken sermon and liturgy, and secondly for the vocal harmonisations made possible by the layering of voice which occurs in highly reverberant spaces where, “as either echoes or reverberation, sounds of the past, at least on the timescale of seconds, exist concurrently with the sounds of the present.”[iv]
Present manifestations of ancient wisdom:
Over centuries, the aural-architecture of spaces of musical performance (in the Western Canon ofter spaces of worship with lengthy reverberant qualities) began shaping the types of music preformed, and therefore also experience and expectation of audiences. Naturally, after centuries, musical forms developed which worked specifically within the particular acoustic context inherited from the spaces in which they were presented. As time continued to pass, musical forms became dependent on these qualities, so much so that the success of swathes of the Western Canon depended on aural-architectural factors.
Ultimately, the direction of musical development came to require the creation of spaces specifically designed for their needs, with musicians working in tandem with architects to imbue spaces with properties suited to the needs of their art. In the present day, aural considerations are central to the design of spaces set aside for listening. For instance, in contemporary concert halls a fine balance must be struck between clarity, reverberance, uniformity, and projection, such that the sounds of each individual player can be picked out by keen ears of the audience members, irrespective of their position within the space, while also blending into the combined effect of the orchestra as a whole. The closeness of this parallel, inter-influencing development is well documented, and has given rise to some of mankind’s greatest explorations into the application of the science of acoustics.
A short lament:
Of course it makes total sense that the aural senses are privileged when it comes designing musical spaces however, as a product of hearing, auditory spatial awareness plays central role in experiencing all built spaces, musical or otherwise.
Herein lies the profound relation of auditory spatial awareness, and by extension our aural faculties, to the experience of space in general. When acoustic considerations are overlooked by designers and architects, what is built is a world which is easy on the eyes but hard on the ears. These spaces, while they may appear wonderful, may end up being at odd with the activities they were designed to enclose by virtue of the incessant openness of hearing.[v]
In writing this, I find my thoughts frequently returning to the differences between the design of concert halls on one hand, and that of a classrooms on the other. In both cases the acoustic properties of space are essential, however it is seldom the case that a classroom has as acoustics conducive to education. I've found myself reflecting, and wondering about what might be... Yes, we have many means to modify the acoustic qualities of a space after the fact, but what a better sounding place the world could be if more attention were afforded to hearing during the design?
[i] While this chain of cause and effect is responsible for most of what we hear, there are those vibrations which do not affect the basilar membrane; those which are felt physically, or experienced in imagination or memory. For an excellent overview of these ‘non-cochlear’ sounds, please find Dr. Malcolm Riddoch’s essay ‘On the Non-Cochlearity of the Sounds in Themselves’ available here; http://malcolmriddoch.com/wp-content/ uploads/2012/10/riddoch-on-non-cochlearity.pdf
[ii] As Salomé Voegelin observes; “the fact that I do not listen […] does not mean that these sounds do not shape the relativity as it presents itself to me”.
– Voegelin, Salomé. “Listening.” In ‘Listening to Noise and Silence: Towards a Philosophy of Sound Art’, 3 - 40. New York: Continuum, 2010. 11.
[iii] See; https://sites.google.com/site/rockartacoustics/ and Waller, Steven J. “Intentionality of Rockart Placement Deduced from Acoustical Measurements.” In ‘Archaeoacoustics’, ed. Christopher Scarre and Graeme Lawson. Cambridge: McDonald Institute for Archaeological Research, 2006.
[iv] Blesser, Barry, and Linda-Ruth Salter. “Auditory Spatial Awareness.” In ‘Spaces Speak, Are You Listening?: Experiencing Aural Architecture’, 11- 66. Cambridge, MA: MIT Press, 2007. 16.
In relation to this point, we can consider how rhythmically complex musics developed in open, outdoor spaces would be unlikely to find successful origins in reverberant spaces of this sort.
[v] In the absence of ‘ear-lids’, aural-architecture has a profound role in all spatial experience, the relevance of which is by no means limited to concert-halls.