While exploring the upper register of the contraforte, I discovered whistle tones by employing a specific fingering technique and applying pressure to the back of the reed with my teeth. I am sure more contraforte players will come up with variants on this.
This effect can be heard in Alberto Posadas’s piece for solo contraforte, Ga :
The whistle tone was also used in Johannes Kalitzke’s ensemble composition, Werckmeister Harmonies 2022, written for Klangforum Wien 2023. This excerpt from the live performance features a Heckelphone solo before the contraforte whistle tone of G7.
Contemporary Contraforte 