Last Friday we were treated to a brilliant Lunchtime Talk by Artist and Studio Resident Kathy Hinde. Over the autumn, Kathy Hinde has been researching and developing a new vocal work that combines live singing with electronically altered voices. The piece is inspired by how bats echo-locate by using sound to ‘see’ their surroundings and the project aims to employ bio-mimicry as a creative method. In collaboration with technologists Matthew Olden and Tarim, Kathy has been creating a new device that uses sensors and mini-computers. These devices effect the sounds of the singers voices based on where they are positioned in the performance space. This is a sonic and spacial experience.

Kathy was joined in the Studio by Professor Gareth Jones, head of the Bat Ecology and Bioacoustics Lab at Bristol University who explained some of the details of how bats echo locate and highlighted the connections between bat behaviour and the structures and methods used to devise of the vocal work.

Kathy opened the talk by describing her background as an artist; her work is largely concerned with the natural world from animal behaviour to the movement of water, ice or land formations. She often works collaboratively and enjoys observing how starting points can be taken in different directions, and unexpected journeys and ideas can appear. She explained that Vocal Migrations really changed and shifted throughout the creative process, due to the collaborative nature of the piece.

Kathy has been interested in Bats for quite a long time and she wanted to find out more about their behaviour, and understand how they use echo-location in more intricate detail. At the start of the project she met up with Professor Gareth Jones and went on a Bat Walk at Priory Park in Bedford, with Bedfordshire Bat Group.

Gareth then explained that it is not simple for us to understand biosonar (how bats echo locate) because we don’t experience anything like it ourselves. Most humans experience their surroundings mainly by vision whereas bats inhabit a largely auditory sensory world. He explained it’s not possible to listen in on bats echo-locating because they use ultra-sound. Gareth then showed us a demonstration of how bats use echo-location, which you can watch here.  
 
Kathy then went on to explain her aims for the project, which were to; describe and navigate around a space using sound, and to create a performance with an echo locating choir modeled on Bat behavior. In order to achieve these aims she decided to create the ‘Bat Box.’ The Bat Box is a mobile audio processing ‘instrument’ that mimics the ways bats echo-locate. Inside the box there is a Raspberry Pi running a Pure Data patch, an Arduino, a ultra sonic distance sensor, a griffin imic sound card, a microphone, a small speaker, batteries and lots of wires. The Bat Box uses data from the distance sensor to change the playback of a vocal sample. When creating the ‘Bat Box’ She decided to focus on two particular strands of bat behavior:  

Echo delay
The distance sensor changes the echo repeat rate of the sample, meaning that when you are in close proximity of another object it plays more frequently.

Change notes
The distance sensor modulates the sample meaning that if you are within a close proximity of another object you get more variations in notes.

Kathy worked with the Bristol Feral Choir, Victoria Bourne and Bedford Community Choir throughout devising Vocal Migrations. She started off working on acoustic experiments with the choirs while the Bat Boxes were still in development, to help the group bond and to explore non-lyrical sounds they could use in performance. After introducing the Bat Boxes to the choir they worked together to create “open scores”, Kathy explained she used “open scores” to try and generate group improvisation - assigning behaviours rather than fixed scores or necessarily linear structures.

What next?
Kathy explained that the Bat Boxes they have created are a working prototype. The next stage is to decide how to design a nicer more user-friendly interface. Kathy explained that she also wants to improve some of the equipment within the box, by buying better microphones and speakers so that they boxes are capable of capturing the singers’ vocals better.

The Bedford Community Choir performed with the Bat Boxes at a Work in Progress event at Bedford on the 8 August 2012, where the post show discussion ‘cafe scientifique’ was chaired by BBC Radio 4’s Quentin Cooper, presenter of Material World.

After the Lunchtime talk we moved into the kitchen and were treated to a demonstration of the Bat Boxes in action.   

Discussion  

Have you tried to use the Bat Boxes it blindfolded?
We did try that a little bit, another possibility for this is that it would be a installation piece, where you get blindfolded, kitted out where people have to go into a space and navigate around using the boxes. It’s something we defiantly talked about.

Have you worked with a choreographer?
I haven’t worked with a choreographer no, but it would be really interesting. We worked with lines and concentric circles and clusters. When I worked with the group in Bedford we did talk about working with a choreographer but there seemed to be something quite nice about the naturalness in movement, and due to the discovery in sounds you need the freedom to be able to walk around quite freely.

You say you envisage the technology changing so it’s not in a box anymore, what do you want it to be like?
I’m not totally sure, but I’d like it to be more wearable. We’ve refined the controls quite a lot during the process so some of the buttons aren’t in the best places anymore, so we’d like to make it a bit easier to use. I’d want it to be more discrete in the later versions.

What’s the highest echo locating bat frequency you’ve ever heard of?
It’s about 210khws, it’s even difficult to detect with bat detectors. Most are between 20-60khws. The ones you can hear at night are actually social calls, they use them when they’re defending food patches and in the autumn the males produce them over and over again to attract the females.

Did you encounter any obstacles with the technology and getting it to develop the way you wanted it to?
Yes, quite a lot. The Raspberry Pi is really cutting edge, and it shows. You’d Google problems you have encountered and you’d find quite a lot of people asking the same question, but no solutions yet. The attraction to the Raspberry Pi is that it’s cheap so it would be easy to scale up.

Do you think it would be possible to develop the sensor in the Bat Box to tell the difference between people and walls?
I’m not quite sure how you would do it, but it’s probably possible if you had much more expensive equipment. In theory it could be done, they have sensors that check oil in rock beds, that can measure different textures and depths but it wouldn’t run on a raspberry Pi.  

Kathy has been blogging extensively throughout the creative process, so for a more in depth look at her process visit her blog here.