Composing for bionic hearing; special musical performances for the Cochlear Implanted

Art Press Release from Australia. Published by Rebecca Gabrielle Cannon on Wednesday 02 February 2011.

Composing for bionic hearing; special musical performances for the Cochlear Implanted
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Melbourne, Australia People with normal hearing use 3,500 hair cells for aural perception. With a Cochlear Implant, 22 electrodes replace those cells. A group of sound artists have designed a series of musical works specifically to be enjoyed by those with bionic hearing.

INTERIOR DESIGN: Music for the Bionic Ear (cochlear implant) presents six pioneering new musical works written specifically for cochlear implant users.

Musician, composer and sound artist Robin Fox lead a group of five other composers in collaboration with researchers at the Bionic Ear Institute. They developed and tested new sounds and musical forms both in the laboratory and with cochlear implant users themselves. These tests have resulted in unique new approaches to the composition and diffusion of musical ideas and sensations.

Although Cochlear implants restore partial hearing, it’s not at full quality. The limitations of the technology are described in detail below. When it comes to hearing music, the main problems are perception of pitch (the sensation of notes going up or down the scale) and timbre (the tone colour, or sensation that makes different instruments playing the same notes still sound different). For someone using a CI, it’s very difficult to tell different notes on the scale apart, and it’s also very difficult to tell the difference between different instruments.

The concert is designed to be enjoyed by both cochlear implant users and audiences with normal hearing. There are over 1,000 Bionic Ear users in Victoria today. For these people the Bionic Ear brings sound into a previously silent world, and for the most part allows them to converse with friends and family. However, listening to live music can be a difficult, or even an annoying experience! INTERIOR DESIGN: Music for the Bionic Ear aims to address that problem.

These works will be performed at a landmark concert in February 2011, where people with bionic and acoustic hearing will be able to enjoy and discuss their experiences together, perhaps for the first time.

Robin Fox and the Bionic Ear Institute have both contributed directly to Melbourne’s reputation as a centre of innovation in both musical creativity and medical bionics. INTERIOR DESIGN will bring these partners together, resulting in a significant body of new musical works, a new dialogue between the arts and the sciences, and will enrich the lives of hearing-impaired music lovers.

COMPOSERS: Robin Fox, Natasha Anderson, Rohan Drape, Ben Harper, Eugene Eughetti, James Rushford

PERFORMERS: Golden Fur, Speak Percussion, the composers.

TWO PERFORMANCES: SUNDAY, FEBURARY 13th at 5:30pm and 8:00pm, with 7pm lecture for ticket holders. Admission to lecture free and space is limited.

TICKETS: $25/$15 concession. Available from the Arts Centre, 1300 182 183,

www.theartscentre.com.au

Why are we doing this?

Although cochlear implants restore the ability to understand speech amazingly well, some CI users often complain that music sounds muddled or confused, and many often switch off their implants, or else try to avoid social situations where music will be present. In today’s society, where music is everywhere, this can lead to people feeling isolated or rejected. The aim of this project is to come up with a series of specifically-made, new musical works, that will be able to be enjoyed by CI users, as well as their friends and families. If hearing-impaired and normal-hearing listeners can discuss the gig together afterwards, without the CI users feeling like they’ve missed out, or heard things “wrong” – it will be a success!

What is a Cochlear Implant?

A cochlear implant is a device that restores auditory sensation for people who have a profound hearing loss. It has two main parts. There is a microphone and sound processor, usually worn clipped behind the ear. This looks a little bit like a hearing aid, and its job is to convert sound waves to an electrical signal. The signals are then sent over a wireless link through the skin to a device implanted in the bone behind the ear. From here the sound signals are converted into electric pulses, and sent to a tiny spiral-shaped array of 22 electrodes inserted into the cochlea, which is a part of the inner ear that normally contains about 3500 hair cells which are responsible for converting sound waves into nerve signals sent to the auditory nerve and the brain. The hair cells are generally all lost in deafness, and these 22 electrodes take the place of the 3500 hair cells, stimulating the auditory nerve directly. This system works really well for understanding speech, especially in quiet places, but is less effective for understanding speech in crowded places, and not good at all for listening to music. Each electrode roughly corresponds to a single perception of pitch, so you can imagine compressing a normal keyboard, with 88 keys, into 22, and you can start to see the problem.

How does music sound through a CI?

It’s difficult for a hearing person to ever know exactly what any sounds are like through a cochlear implant – it’s a bit like asking someone to describe what it’s like to see the colour red, without resorting to analogies “like a rose” or other examples. However, people who had normal hearing for some period before going deaf sometimes say that voices sound robotic or metallic. For music, the main problems are perception of pitch (the sensation of notes going up or down the scale) and timbre (the tone colour, or sensation that makes different instruments playing the same notes still sound different). For someone using a CI, it’s very difficult to tell different notes on the scale apart, and it’s also very difficult to tell the difference between different instruments. Obviously this has a huge impact on listening to most music, which is mainly based on following melodies containing intervals of 1 or 2 whole tones, and following lines of melodies played by different instruments at the same time.

How does this project work?

The idea is very simple – Robin has recently been awarded funding through ANAT (the Australian Network for Art and Technology), to spend 3 months in a residency at the BEI. During this residency he’ll learn in detail about how the normally-functioning auditory system works (all the way from the ear drum to the brain), and the causes and mechanisms of hearing loss. He’ll also learn how hearing loss affects the perception of music, and quite a lot of details about how cochlear implants work – exactly how the signal-processing parts of the sound-processor work, and how the electrodes help create auditory sensation.

Robin will also be in charge of co-ordinating the other 5 composers, and organising meetings between the scientists and engineers at the Institute, as well as the CI users themselves. We’ll also teach them about the particular strengths and weaknesses of cochlear implants, what parts of music come through well, and what parts might be lost. The composers will then use this knowledge as a kind of structure or scaffold to guide their compositions. One of the problems with CI users listening to existing music is that it’s often quite restrictive in terms of using the normal Western 12-note scale, and there are a lot of written and unwritten rules about all aspects of music – from rules of composition right through to accepted methods of playing instruments.

The rules are actually based on various rules from physics and acoustics – for example, a consonant chord is a happy-sounding chord, and is produced by playing a series of notes whose harmonics (or overtones) all align and reinforce each other. A dissonant chord has at least one note with harmonics that don’t fit that pattern, and can sound grating or uncomfortable. All these perceptions of consonance and dissonance rely on the normal functioning of parts of the inner ear, and don’t necessarily work for someone using a CI. Many of the rules don’t really make sense, or aren’t useful for composing music for someone using a cochlear implant. The NEW rules that we’ll develop as part of Robin’s residency will be based on how implants work, rather than solely on the normally-functioning auditory system.

Who’s involved

We were very pleased to receive $15,000 from the Australia Council of the Arts, $11,550 from Arts Victoria, and $5000 each from the Cochlear Foundation and the Bionic Ear Institute to support the commissioning of five composers in addition to Robin. They are Natasha Anderson and Ben Harper who along with Robin are making electroacoustic works, Eugene Ughetti from the Speak Percussion Ensemble, James Rushford, who plays with Golden Fur in Melbourne (just back from a huge tour in Europe), and Rohan Drape, a composer who has written works for all sorts of instruments – from “slave pianos” to computer-controlled Tesla coils. The composers that Robin’s chosen for these works are all quite experimental in their approaches to music, and won’t be constrained by traditional rules of composition and performance. A variety of people at the BEI are involved – myself, Jeremy Marozeau, who leads the Music and Pitch team at the BEI, and both of our deputy directors – Prof Peter Blamey, who invented ADRO, one of the most successful hearing aid sound-processing schemes, and Prof Hugh McDermot, who invented the most widely-used cochlear implant sound-processing scheme. We’ll also be working closely with a number of people from Cochlear Ltd, who actually build the devices – so we have a huge reserve of knowledge, a lot of it from the people who actually designed and build these remarkable devices.

- Hamish Innes-Brown