Disclaimer: this is a work by myself and Tori Holmes, Nico Espinoza and Rafel Puetter (Rafucko). We have a dedicated website for this installation here where you can read all details about the mappings. I will give a quick introduction below and you can read more on the website. I thought it was long overdue to get a post about this work on the sonification art blog as well.
Outros Registros is a 8.1 installation that sonifies police violence in Rio de Janeiro between 2009 (when Rio was selected as the Olympic host city) and 2016. The monthly data are played back at a rhythm of 30 seconds/month and consists of three layers: A constant “drone”, made up out of individual sinewaves, represents civilian deaths, mapped onto the four geographical regions of Rio, and combined with data for the city as a whole. These frequencies beat against eachother and cause rhythms to emerge. The second layer is a bell-like sound, which juxtaposes the data on police and civilian deaths to create a kind of melody. The frequencies for each zone are converted to MIDI-notes and played with a random delay within the 30-second window. Finally, the sonification of civilian and police deaths is also mixed with a third element, the sound of a human voice reading aloud newspaper headlines relating to police violence. The different sound sources also move around the circle created by the speakers, at different speeds and in different directions. For a more detailed look at the mappings, you can read a paper here.
You can listen to a sample of the sound here:
During the second staging we made a video about the installation. This staging was linked to a workshop organised by the “Dialogues on Public Security: Experiences in Brazil and in the UK” project (link in Portuguese).