Andriessen's music is emphatically anti-romantic. It is not capricious, compulsive or acrobatic. Andriessen's compositions are hierarchically structured, hewn as it were from blocks of stone, and the prima materia of these blocks is the tone. It is measured music. The rhythmical structures are plotted along the musical millimetre markings of a basic pulse.
Vibrato is a deadly sin.
He demands that the tones played by the musicians should be as straight as a ruler. The players must attain the utmost concentration, endurance and precision. In this sense, it is virtuoso music. Andriessen follows no recipes. He is by nature an experimenter, but of the type that is deeply concerned with the conditions under which the experiment is carried out.