“Aceton (‘Acetone’), composed for four electric guitars and live electronics in 2008-9, is generated entirely by a special computer programme, i.e. the score is created by pre-defined algorithms with limited random decisions. Each time the programme is run it produces scores with slight discrepancies. The scores, though identical in overall shape and phenotype (e.g. pitch ranges and time frames), differ in several details on the micro-level. To create an Aceton score, i.e. one version of the piece, the composer runs the programme several times and chooses one of the calculated results. This result is then adapted to meet the conditions of the performance; the performing musicians correct as necessary certain inaccuracies related to their instrument. Aceton thus alternates between pre-programmed contingency and determinacy and combines variability with teleological rigour. The players know very well what will basically happen, but they can’t predict how and what will take place in particular. That, at any rate, is the conceptual idea behind the score. None of this is apparent to the listener of Aceton, who knows nothing of its complex genesis or the composer’s decision-making criteria. The listener is confronted solely with the acoustical result.

The impetus for Aceton came from a factual report, an experiment. In August 1952 the weather service predicted rain on the southern coast of England. It rained for 24 hours. Rivers overflowed their banks, flashfloods surged through the coastal town of Lynmouth (in Devonshire), inundating the town and drowning inhabitants. Local residents reported seeing several aeroplanes circling before the floods occurred. The BBC investigated the event.

A pilot admitted to spraying large amounts of salt that day. The British Ministry of Defence denied conducting secret weather experiments – for a long time. Fifty years later the secret files were declassified, confirming long-held suspicions that secret weather experiments had taken place as early as the 1950s (the project was called ‘Cumulus’ at the time). Rain can be created artificially by ‘seeding’ clouds with silver iodide. An acetone solution mixed with silver iodide releases water-absorbing salts that combine with ice crystals and fall downward because of the increased weight. They then melt, and it rains. Much the same happens in Bornhöft’s Aceton, which conveys this background with purely instrumental means. It also makes use of the explosive force of highly volatile acetone peroxide (APEX) and the corrosive dangers of colourless CH3COCH3 – for purely musical purposes, of course. But aesthetically, too, Aceton is ‘danger music’.”

(German text: Stefan Fricke, English translation: Dr. J. Bradford Robinson)