One of the first decisions I had to make when I started writing these pieces was this: both the sources I was using had singers, and texts. Should I use one or two, or no, voices in my piece? I decided to take what seemed like the riskiest course of excluding the voices and texts altogether. Mostly because I wanted to focus on the musical processes that were at work, which, though made explicit by the texts in some ways, are also somewhat obscured by them in others. And anyway, I thought, the texts are always there for people to find if they really want to know them. I still retained the musical content of the voice parts, though, as that was a significant part of what defined the musical process.
So, at this point I had all my material transcribed and some of it already developed along the lines I described in the last entry; I had made some key decisions about the final outcome, and I had a good idea of the instruments I had at my disposal: soprano saxophone, electric violin and guitar, double bass and keyboard. All I had to do now was find some way of making this all fit together.
About this time I was talking to Andrew Porter, a PhD student in the lab. He was developing some software called wormtracker which uses video footage of the worms to record their motion, changes in position and speed. This seemed interesting to me as any information that is related to change over time has musical potential. He kindly sent me some of this data, which I decided would be a good way to control the way in which my two sources could be combined. Because the concept driving the choice of material was the relationship between mood and motion, and the fact that I had developed the material to a certain degree already to emphasise the contrast between the two pieces, it seemed a natural step to use actual data from experiments exploring these ideas too.
I had a few data sets, from worms that had been put on a variety of substances that effected their levels of serotonin and therefore locomotion. I chose two sets: one from worms on PMA (phorbol 12-myristate 13-acetate), a chemical that acts on a certain protein pathway inside the motor neuron cell with the effect of making the worms move more speedily, and one from worms on serotonin itself which makes the worms remain rather still.
At first I tried using X and Y co-ordinates of the change in position to govern changes in the source material, but having two data points for every musical one seemed unconvincing and conceptually clunky, so I ditched that idea after wrestling with it over Christmas. I then realised that the best way of using the data was to extract the speed of each worm at each given point.
This is a graph that shows the combination of the two data sets, the pink one is the worm on serotonin, the blue one on PMA. The serotonin data changes more frequently but stays more or less in the same range: the worm is quite still and not moving very much so the changes are small. The PMA worm has a wider variety of speeds as it is more agitated.
I transformed the numbers slightly to give me a percentage over the range of different speeds for each point, and used that number to determine the percentage of musical material from either source that was present in each bar, which as you can see from the graph varies from almost zero to 100%. Thus the pink line controls Der Abschied and the blue one Hejira. Once I had sculpted down each song, all that remained for me to do was to superimpose them and arrange them for the ensemble. Here’s a taster of the computer version, though it will sound quite different when [rout] play it. I decided to call it Porous with travel fever/ PMA and serotonin.
Porous with travel fever/ PMA and serotonin (extract)
I'll explain what I did next for the other piece next time.