Rhythms of the City by the artists duo Mar Canet Sola and Varvara Guljajeva sonifies online activity in specific cities. The overall activity on Youtube, Twitter and Flickr are measured and compared to historical activity. The resulting value is mapped to a tempo value on a metronome. The more activity there is in a city, the higher the tempo of the corresponding metronome. The combination of various metronomes, each one representing a different city, results in a polyrhythmic total. This works bears some resemblance to Ligeti’s Poéme Symphonique for 100 Metronomes however, as the metronomes have to keep a tempo, they are fitted with Arduino-controlled motors to allow the never-ending social activity to be sonified.
The artists have created Speed of Market, a variation on the installation, using data from 7 stock markets (NYSE, NASDAQ, JAPAN exchange group, Euronext, London Stock Exchange, Hong Kong Exchange, and Deutsche Borse). Their trading volume (the number of stock traded) is mapped to the tempo so the bigger the volume, the faster the metronomes play. During the weekend, when no trading is happening, the metronomes are stationary.