This work explores the psychoacoustic phenomena of difference and combination tones as compositional material. The non-linearities of the inner ear are responsible for otoacoustic emissions which cause the ear to produce its own audible sounds when provoked by certain stimuli. When subjected to two stimulus tones (f1 and f2) the ear will, under suitable circumstances, produce distortion products with frequency relationships to the two stimulus tones equivalent to f2- f1 and/or f1+f2. These tones will sound something similar to a soft buzzing, ringing or rumbling when present.

In this piece the ear is responding to sounds that are presented within simple and complex structures. A powerful sensory journey is experienced in Invisibilia. Each audience member will hear their own version of the work in many respects as these 'phantom' tones will differ in type and intensity from listener to listener.

Invisibilia causes the listener's ears to become instruments. The ear is no longer a passive sensory organ in the listening experience. Here, it is considered to be an active participant in the musical process.

Invisibilia

At any given point in this demonstration there are just two high frequency tones playing simultaneously and they are randomly placed.

The psychoacoustic phenomena of 'difference tones' are used in this demonstration to provoke otoacoustic emissions from the inner ear which are manipulated to be presented in the tune of Twinkle, Twinkle, Little Star. The only non-random element of the high frequency tones is the set difference between them at any given point. 

This demonstration is most effective through headphones and it starts 8 beats in (if the tones playing as semiquavers). The Twinkle Twinkle melody line will be heard at a much lower register than the random tones and it is 100% coming out of your ear and not into your ear. These OAEs will be heard as a low-level buzzing. Try to not listen to the high frequencies!

“Otoacoustic emissions (OAEs) are sounds of cochlear origin, which can be recorded by a microphone ftted into the ear canal. They are caused by the motion of the cochlea's sensory hair cells as they energetically respond to auditory stimulation.”
- David T. Kemp

Twinkle, Twinkle, Little Star as otoacoustic emissions

Over two short movements Track exploits the non-linear nature of the inner ear in relation to the phenomenon of pitch perception within complex non-periodic sounds. Through both knowledge of bandwidth phenomena in relation to basilar membrane functions of the inner ear combined with specific equalisation, filtering and spectral masking procedures, this work involves the generation of formant regions with specific centre frequencies and modulating bandwidths which the listener's ears will unintentionally track throughout the duration of the piece.

Part 1: 'Pitched' Non-Periodicity 
(3:59)

The source material for this work is solely comprised of pouring water, dragging metallic pipes, chains and glasses, all of which exhibit inharmonic waveforms. 'Pitched' Non-Periodicity forces the listener's ears to move from being passive receivers of spectral information to becoming active participants in the realisation of this work. While much is known regarding the science of the listening process, a lot remains to be discovered in relation to the full extent of the non-linear nature of the inner ear and this work seeks to employ such concepts at the heart of its creative methodology. As the listener's ears become instruments in the performance of this piece, a bridge is formed between the physicality of the listener and the loudspeakers with the sound waves now behaving as sonic stimuli which place the inner ear of the listener at the forefront of the work itself.

Part 2: Percolated Audio
(4:12)

In contrast to the opening movement this section is comprised predominantly of synthetic sounds which also includes harmonic material for the first time in this work. An added emphasis is placed here on the listener's ability to track peak frequencies within inharmonic material as this section demonstrates a significantly reduced sound world in relation to timbral colour. Percolated Audio explores a heavy use of filtered sounds with moveable bandwidths which present the inner ear with a new dilemma as the listener is exposed to more direct sounds which often appear to already have clear centre frequencies yet the movement of the filters causes the listener's ears to track the extremities of the bandwidths rather than conducting more simple pitch tracking procedures. 


Track

Waves explores the creative potential of combining the application of psychoacoustic phenomena with more traditional compositional methods. Through the employment of auditory beating, spectral masking and the residue pitch phenomenon this piece requires the listener's ears to become active instruments in the performance of the music while the live electronics strive to both augment and alter the tonality presented by the strings.

Waves

This experimental work explores the creative potential of the missing fundamental phenomenon and causes the listener's ears to become active instruments in the realisation of work itself. This facet of psychoacoustics allows the ears to be manipulated in such a way that fundamental tones can be heard without being present in the loudspeaker signal. These perceived tones are auditory distortion products known as residue pitch which are produced by the ear itself. The composer takes advantage of the hearing system's pattern recognition approach to processing periodic sounds in this work. 

The electronic part simply presents sixteen sine waves, each an integer multiple of C1 (32.205Hz) beginning with the first overtone and rising. Throughout the course of this piece the overtones are delicately removed from the bottom up. This creates a change in timbre but not a change in the perceived C1 tone which the audience's ears will generate.

The cello part explores the lowest two partials that are present in the stack of sine waves at any given point. As the intervalic distance between the partials decreases with increasing height the room for movement in the cello part becomes significantly restricted and so a sense of frustration and increased energy is presented over the course of this work.

Eoin Kenny (electric cello)

Occultum Tabulatum (stereo)

Oscima is a modern exploration of a methodology which was first presented by Alvin Lucier in his work Crossings (1982) in which the nature of auditory beating was presented in a compositional paradigm. Oscima takes Lucier's concept of static tones with a frequently intersecting sine sweep to a new domain by placing a bank of noise-based resonant filters over a sine wave while their bandwidths shift constantly around fixed centre frequencies.

This work investigates the impact of the listener's proximity to the various loudspeakers on the provocation of auditory beating on their ears. As the sine wave enters the spectral regions of the various filters the two components begin to interact with each other and auditory beating and roughness is heard. At no point are the filtered noise and sine wave being omitted from the same stereo position in the performance space when their frequency regions cross and at these points the beating is entirely being generated within the listener's ears which are quite literally used as instruments in this immersive and physical work.

Oscima (stereo)

Maeple encapsulates Alvin Lucier's school of thought concerning 'simple procedures yielding complex results'. This piece spotlights the creative potential of the non-linearities of the listening system relating to the basilar membrane of the inner ear and the connecting auditory nerve.

A combination of spectral masking, binaural beating and residue pitch results in the listener's ears performing the essence of this work. Each listener will physically feel their ears performing this piece and if the listener turns their head during a live octophonic performance it can often entirely change the colour of the sound in this immersive work.

Maeple (stereo)

This piece uses binaural beating as a timbre modulation device. Critical Bands is intended for an enhanced stereo performance (four pairs of two loudspeakers), within which the listener will experience the phenomenon of intracranial motion (perceived movement as a result of binaural beating). 

Source material for this work includes piano, electric guitar, flute, cello, crash cymbal, metal, computer hum, glockenspiel, electric double bass as well as entirely computer-generated sounds.

Critical Bands (stereo)

The non-linearities of the inner ear are responsible for otoacoustic emissions which cause the ear to produce its own audible sounds when provoked by certain stimuli. Transcape generates transient evoked otoacoustic emissions (TEOAEs) in the listener's ears which become the cornerstones of work itself. This work directly investigates TEOAEs through the use of noise/ tone bursts and clicks within an artistic context.

Transcape

Chase is a work which is loosely influenced by early minimalist piano repertoire in its exhibition of subtle, yet consistent, changes taking place within limited material as a means of gradually expanding/altering the original themes. The electronics in this work seek to remove the sonic product from any element of aesthetic similarity to what may be deemed a more familiar minimalist piano music, through the application of auditory beating (monaural and binaural) as well as through spectral masking procedures.

Chase (stereo)

"Panic Along the Coast"

My inspiration for this composition originated with my intention to create a work which would be an exploration of the movement of sound in a given space whereby the listener could imagine themselves placed firmly inside a particular scene. I decided to compose a piece depicting a tornado coming in from sea and traveling over a coastal village. I chose this idea due to its scope of creative possibilities especially in the areas of dynamic levels and panoramic movement.

A fundamental tool in my writing was the use of white noise. I have a fascination with the vast range of sound that can be created by white noise as it encompasses all frequencies in equal measure. This composition was a perfect opportunity for me to explore this interest further due to the fact that, when filtered/ processed accordingly, white noise can be manipulated to sound like wind and water.

"Panic Along the Coast" consists of three sections:
1-Intro (0mins 0secs - 2mins 1sec)
The opening section explores a sense of unease arising along the coastline. Occasional variations of sounds which relate to that of a ship's sonar system (first presented at 7secs) have been used to depict the sea, as well as the sound of ship's 'whistles' in the distance. As seabirds flock in towards the land a sense of unease arises and alarms are raised in the village to notify the community.

2-The Calm (2mins 1sec - 5mins 8secs)
Thunder is heard arriving along the coast as the weather takes a turn for the worst. Wind-chime-like sounds give the sense of local inhabitant's homes slowly being approached by the edge of the tornado. The threat of the tornado is so strong that it feels as though its base is gripped into the depths of the sea like the talons of a bird of prey clasping on to its next victim. The community is given a moment of calm but they are aware of what is about to arrive. The tornado is portrayed here as a beast which breathes in an intimidating manner onto the coastline to announce its arrival.


3-The Storm (5mins 8secs - 7mins 0secs)
The tornado has arrived over the village and debris begins to fly around the place in all directions. Alarms are going off and the community remains helpless as it passes over. The tornado passes in a relatively short space of time but the village does not feel safe just yet as, once the tornado passes over, it turns back in the direction of the village as if it is mocking the community, pretending as though it will strike again which much more disastrous consequences, however it soon sweeps off in the opposite direction once more and the village is safe again.

This composition has been played at Riverstown Hall, NUI Maynooth (Nov 2011) and at the Hilltown New Music Festival (July 2012) 

Panic Along the Coast

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Most compositions are best suited for headphone playback.

Please note: audio compression may cause distortions and these works are predominantly stereo reductions of octophonic works.  

Brian Connolly is a composer, sound artist and psychoacoustician from Dublin, Ireland with research interests in the application of psychoacoustic phenomena concerning the non-linearities of the inner ear within composition. Since starting his PhD in 2012 at Maynooth University, Brian has composed the music for Keith Barry's The Dark Side tour as well as having written and presented the Irish national radio documentary Why Music Can't Stay Still. Brian is also the producer of the iTunes award-winning podcast An Irishman Abroad. Brian's teaching duties at Maynooth University include lecturing acoustics and psychoacoustics at undergraduate and postgraduate level.

The composer's ground-breaking research into the ear as an instrument has been accepted for inclusion in programs with SMC, Music Current and ISTCC (Ireland), NI Science Festival (Northern Ireland), TIES (Canada), INTER- (Scotland), INTIME, SSC and BEAST FEaST (England), ASA and FEASt fest (USA), MUSLAB (Mexico) and NAA (China).

Brian Connolly

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