“the bone conductor” research presentation during the Global Composition Conference, 2018

2018     keynote presentation at  The Global Composition 2018 Conference  on Sound, Ecology, and Media Culture  in  Darmstadt-Dieburg,  Germany,    WFAE, World Forum of Acoustic Ecology, October 04 – 07, 2018

titel:  “the bone conductor” – project: to gain more inclusive knowledge of  the sound habitat by sharing multi sensory hearing experiences of sight- and hearing (dis)abled people.

The project started end 2017 with the presentation of the interactive tactile sonic installation: “woollen sound bone” combined with bone conducting headphones, creating an intense, intimate, personal multi sensorial hearing perspective (creative research) as playful introduction to principles of bone conduction.  Here more about the start of the project.

                                                               principles of bone conduction

Bone conduction is always part of our hearing perspective. We receive the sounds from outside and inside our body, always influenced by the vibrations of our own (cheek) bones. It is adding subtle warm tone colours when hearing our own voice but our voice sounds different when we hear a recording of it. The bones and organs in our body are constantly conducting subtle and lesser subtle vibrations in several frequency ranges. So we are literally part of our surrounding sound habitat, in which we move around, while hearing, listening and feeling the sounds with our whole body. We are conductors of our own sonic and sensory experiences when bringing it to a more conscious level or not. We conduct, filter and absorb the sound vibrations with our body giving the sensory information context and meaning with our brains. Our “multi sensorial hearing perspective” is also influenced by our haptic habits, how we make contact with the vibrational surroundings, the material of the floor we are standing on, machinery, others, etc. 

                                                                     short historie

Around 1550 there were a lot of discoveries about the anatomy and working of the ears. First the outer ear, pinna and ear drums, a bit later the discovery of the middle ear, including the three small bones with the little hammer and the inner ear with cochlea. The Italian physician and philosopher Girolama Cardano was the first writing about the principle of bone conducting. He describes how the sounds could become audible when conducted to the ears by holding a rod or the shaft of a spear held between one’s teeth. [2] Around 1757 the bone conduction principle was “rediscovered” as hearing aid by the German Jorrison. He was sitting next to a harpsichord and accidentally touching the instrument with the pipe in his mouth and could hear the music instantly. His son was writing a medical paper about is. During the following centuries several hearing aids using bone conducting principles where developed like the dentaphone in 1880. In 1977 started the usage of Bone Anchored Hearing Aids (BAHA) implants. The device became commercially available in 1987. Now a days the principle is used for people with hearing disabilities mostly as an implant anchored in the bone just behind the ear.[3]

Bone conduction works best for people with conductive hearing loss, with a poor or incorrect transmission of sounds through the ears and eardrums. It is less effective for people with perceptive hearing loss or sensorineurol hearing loss, with difficulties sensing vibrations by the auditory nerves at the cochlea. It also can be mixed hearing loss, a combination of these types hearing loss.

                                                              bone conducting headphones

Bone conducting headphones and bone conducting helmets are used for military and strategically purposes already quite a time. The last year’s commercial bone conducting headphones for listening to music during sports activities like running, biking, diving is getting more popular. The sound quality and frequency response is still part of the development. They all benefit of the possibility to hear, getting information, to communicate, and listen to music while still being able to use the ears and not being shut off the sonic environment. This creates more safeness on a basic level when hearing sudden loud or alarming sounds but I think depending of the volume, dynamic, the context of the sound information or the music, it still can be distractful. It still remains easier to (re) connect with the surrounding soundscape than wearing normal headphones on the ears. With fast (commercial) developments there are now a days also standard headphones that are including the positive effects of the bone conducting. It will change our future hearing perspective.

conduct:  “to bring together”

We all sense the sound habitat with personal – and cultural multi sensory hearing perspectives. Also when we are differently sense abled like sight – or hearing disabled. We can be open to “bring together” (conduct) [1] our personal experienced (dis) abilities and qualities, special talents when sensing the sound habitat.

                                            sight disabled, blind people                  

I presented the “woollen sound bone” with bone conducting headphones to sight disabled people. After the presentations I asked them for their name and age, how they would describe their sense disability, if they developed also special sense abilities or talents, how they experienced the bone conductor installation with combination of hearing perspectives, how they experienced the musical elements in it, how they use their senses when navigating through the sound habitat, what they think of the “musical” aspects of their daily soundscape environments, if they want to add or change things in their daily soundscape or in future soundscapes?


Hannes Walrafen and Ton Hulskramer

using  binaural recordings

For “the bone conductor project” I was also inspired by Piet Devos writer and literary theorist who is a blind scientist him self and recently was using binaural recordings as a tool for doing (auto) ethnographic research to share sonic realities of blind and sighted. [4] The shared listening practice when using binaural recordings, including the sounds of the cane, have the ability to evoke memory traces of multi sensory experiences. When listening to the recordings mixed with the conversations about shared personal experiences, using headphones in the same moment, this can create meaningfull knowledge about the differences between persons with different sense abilities. In his article Piet Devos supports the creative use of technology to explore different individual experiences instead of using technology or methods that are enforcing normative tendencies

                                                                presenting the bone conductor

Until the moment of the presentation during the Global Composition Conference “the bone conductor” was presented to Ton Hulskramer [5] and Hannes Wallrafen [6] sepparatly. They both got the rather seldom genetic disease causing them to get blind in a very short period: the eyes are working, moving in a normal way but the eye nerves that have to send the visual information to the brain are destroyed and almost gone. Ton was getting blind at the age of 20 and lost his sight in 2 weeks time from 100% to 7% and now has left 2%. (57 years old in 2018). He is working as a coach for helping unemployed. Hannes was getting blind at the age of 53 and lost his sight during a period of 3 months, he still has some experience of light and dark that helps him during navigating. He was 67 in 2018.

                                           exchanged of hearing perspective

When meeting Ton for the first time at the ferry near my atelier in North of Amsterdam at the IJ, I asked him if he was open for the first experiment: the exchange of binaural in-ear microphones during the recording. He never heard of binaural microphones. I explained that they capture the sonic environment through his ears, pinna’s, as part of his personal hearing perspective, capturing the way he is moving, hearing around, following his path. He was open for it so we “exchanged” our hearing perspective becoming joint auteur of the binaural recording; in the recording the centre position of my voice changed of position and was placed some meters at the left in hearing perspective of Ton. In a way this was a metaphoric and symbolic moment of being open for and sharing the multi sensory hearing perspective with the other. During the short walk to my atelier I immediately felt responsible for his safety and started informing him about all kinds of obstacles on our path as if I had to add my visual perspective to help him.

Ton told me he likes walking alone and doing fast walkings with cane for lots of kilometers as a sport. He is a guy “with blind trust” (the name of his coaching business) not letting the fear control him but using all his senses without seeing to find his way. If needed with great speed even in unknown areas and of course he knows when to slow down in more dangerous traffic situations. He is also able to feel the size building or a large obstacle without touching it. He developed a special talent to sense the aura” and energies of people when they are near enough. In the beginning it was for safety later he could use this as a talent. A small and uncomfortable clash won’t deprive him from his freedom, curiosity and mobility. Sometimes falling is part of it. The unexpected and unknown sound environment is giving him energy. It refreshed my perspective on sensory navigation by blind people. Although I know there are also (older) sight disabled people that suffer immobility, because of fear getting out their homes into unknown areas while causing them a lot of energy to concentrate on finding their path.

Before Hannes was suddenly getting blind he was a known photographer in the Netherlands. Almost immediately after he has gone blind he switched to sound and the experience of sound and became active in creating sound as a sound artist helping the blind community. He wrote a book about this live changing experience: the blind photographer (in Dutch) But first he had to develop his auditive sense to manage walking through the world. Hannes can’t say if the ear is the number one or the tactile touching with the continuous left right moving cane; always using them together making a loud ticking sound with the cane (with porcelain knob) and listening to the sound reflections in the space around. He is not using a roller cane that always stays connected to the ground. Hannes has still a lot of visual images of Amsterdam 14 years ago, but now he is creating and remembering sensemaps (of tactile, sounding, smelling impressions) to find his way on his daily routes through the city.

experiencing “the bone conductor”

When experiencing “bone conductor” they both were really surprised by the combination of sensory hearing perspectives and becoming conductors of the experience when touching the “woollen sound bone” and changing its position. They liked the intense effects of the different sensescapes I composed. The experimental, some times more abstract, musical elements where triggering associations with foreign countries or with the low horn of ship when mixed with fieldrecordings of water. Ton mostly liked the clear and realistic multi sensory experience of water sounds that made him feel quiet and relaxed.


After the presentation he felt relieved and pleasantly light as if the vibrations went through his whole body. He thinks this experience will help creating more awareness of the multi sensory sound habitat.  Hannes specially liked the subtle and transparent sensescape of the Dutch islands because of the clear binaural impressions, the distinction and combination of sounds he was hearing with the conducting headphones and with the “woollen sound bone”. A longer more dynamic drone-like sensescape was too intense for him. 


Becoming a composer of your daily sensescape

Asking them about the musical elements in the daily experienced soundscape they both feel like being composers of their own sensescapes. When they are back home they remember it as a musical composition, enjoying the esthetic aspects of sounds in the space and time lines of the experienced sound events in which they performed.

 Hannes as composer:  


What sounds do they (dis)like, want to change in the daily city soundscapes? 

Hannes hates the sounds of the little cars cleaning the streets with large scrubbers making lots of low noise with high amounts of db. He wants to ban them from the streets. After the interview I tried to make a recording of the cleaning cars but this was almost impossible when coming to close because of the very low noise picked up by the sensitive binaural mics.

Although Ton is really trained in coping with the “cocktail party effect” and is able to hear and distinct the sound information of several sound events at ones, he dislikes it when a place is becoming to crowded because of the (sound) energy of lots of people together. He would like to create regulations for that but also wants to keep his own responsibility. Like in some foreign cities when you almost falling over the garbage in the streets, although you are able to smell it too, as a visitor you can’t change this situation and stay autonomic. Because he likes the sounds of water we went visiting a large sculptured fountain making binaural recordings while walking around it, touching the sculptures with his long cane and feeling the streams in the water with it, to gether enjoying the changing sound perspectives.

Ton and Hannes both are expecting a more quiet Amsterdam city centre with lesser cars and more electric traffic in the near future.  

On a global scale we can enrich our inclusive knowledge of the sound habitat by sharing our personal “multi sensorial hearing perspectives” and become joined creative, responsible performers, conductors and composers of the global composition.

Here you can download the full paper with more information.   (coming)

The keynote presentations are documented on youtube; here you can watch my presentation filed under session “methodes and notions of listening 1” as part of the Global Composition Conference, 2018.

After this presentation I had more presentations for blind and hearing disabled people in 2018 and 2019; all with their personal experienced “multi sensorial hearing perspective”.  

2021  presentation with updates of the project and my ideas about the “multi sensorial hearing perspective” during the (online) Uncommon Senses III Conference, back to the future of the senses, Concordia University, Montreal, Canada.

2022  I had an online presentation of the bone conductor at Workshop 2 of the   Aural Diversity Network. (Universities Leeds and Nottingham).  

2023  Januari I had a physical presentation of the bone conductor for aural diverse audience (including deaf blind) at the Attenborough Arts Centre in Leicester (University of Leicester). Workshop 5 During this presentation I have added live elements: with my voice and EWI (Electric Wind Instrument) creating extra tangible layers of music and voice.

2023   March presentations and tactile drawing workshops for children with multiple communicative disabilities including hearing disabilities at Kentalis Signis CMB, Amsterdam school for special education (cluster 2).


[1] conduct (n.) mid-15c., “action of guiding or leading, guide” (in sauf conducte), from Medieval Latin conductus, from past-participle stem of Latin conducere “to lead or bring together,” from assimilated form of com “with, together” (see con-) + ducere “to lead” (from PIE root *deuk- “to lead”). Sense of “personal behavior” is first recorded 1670s. https://www.etymonline.com/word/conduct

[2] lots of more information about the history of hearing aid: bernard Becker medical library; deafness in Disguise) including time line:  http://beckerexhibits.wustl.edu/did/

[3] information about BAHA  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3068630/

[4] Article co-authored with Florian Grond, published in Digital Creativity: health and wellbeing, pp. 1-17) http://pietdevos.be/en/themes/detail/sonic-boundary-objects-negotiating-disability-technology-and-simulation

[5] website Ton Hulskramer   (in blind trust)    http://thcoaching-inblindvertrouwen.nl/

[6] website Hannes Wallrafen   http://geluidinzicht.nl/_hanneswa/