Brass instruments may be seen as acoustic counting machines, in which the seemingly esoteric mathematical formulas underlying microtonal tuning are made audible through minute adjustments in tube length. Specifically designed valve systems in combination with the slide trombone allow an unprecedented degree of precision in the realisation of microtonal music. The Berlin-based trio consists of the British tuba player Hayward – who developed the first fully microtonal tuba in 2000 – and includes Norwegian trombonist Henrik Nørstebø and American bass trombonist M.O. Abbott. They make their first public appearance at CTM festival.