The Commute - Sonification of the Victoria tube line

As part of the second year of my degree I began development of a piece of software which sonifies data collected from Transport for London about the Victoria underground tube line. Using Pure Data, a "real-time graphical dataflow programming environment for audio, video, and graphical processing", The Commute uses these data collections to create MIDI information, which is currently routed through my Macbook's IAC driver into Logic Pro X where some preprogrammed MIDI instruments listen to each channel and produce the audio output.

The Commute uses a variety of data sets to inform and alter the musical content of the piece. The process begins with a Markov chain process, which generates the root notes of each chord by analysing a MIDI file of single notes in the key of C major. These root notes are used to create the harmony in the music; using the Western key system, appropriate major and minor chords are produced based on the scale degree of the root note produced.

Each train station has assigned to it a key signature, using the circle of fifths to ensure variety in key as the piece progresses but to reduce dissonance. Depending on the number of overground or underground connections, the root note is doubled various number of octaves up or down.

The rate at which a new note is triggered is controlled by the clock. If it is close to, or during, rush hour times, there is a higher probability a note will be triggered. At less busy times, for example between midnight and 4am, there is a lower probability a note will be triggered. The clock can be manually altered and doesn't have to be accurate.

The length of the piece of music directly correlates to the amount of time the journey would take, therefore when taking the train from Walthamstow Central to Brixton, The Commute creates music to last the entire journey. This is demonstrated by the use of actual video footage recorded from the front of the train in the direction of travel, which accompanies the journey.

If using The Commute in 'normal speed', i.e. the time for the music to finish is the time it actually takes to get between two stations, there is accompanying video from the cab of a tube train going through the Victoria line. There are currently some issues with syncing the video to the music generation, but it's pretty close. This feature also causes a bit of lag due to having to load a large video file, however it is turned off if the speed is increased.

This area of music and sound technology isn't one which I would have said I was particularly interesting when I started my degree, mainly because I didn't know it existed, but I have really enjoyed working on this project - it has fulfilled my creative and musical side as well as my nerdy geeky side. I'd be very interested in developing this project to increase it's size and capabilities, such as to include more underground lines and more data sonification. I will keep you updated as I continue to work on it! And if anyone from Transport for London is reading this, please get in touch!

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