Whistles are all built from a basic module with a side slit that acts as a tone hole. The basic whistle module can be combined to create conglomerate instruments such as whistle stacks and whistle trees. This design is adapted from a film can whistle I first encountered from a description by Bart Hopkins of Experimental Musical Instruments. The design Hopkins described was made by cutting a slit in the side of a canister used to hold 35mm film.
Note: all of these designs require:
The version here can be tuned to specific pitches and includes attachment bars on the top and bottom so it can be combined with other instruments to create hybrid instruments.
Whistle stacks generate a tower of whistles all tuned in relation to the base whistle. Changing the ratio between subsequent whistles changes the tuning of the stack. A 3:2 ratio creates a stack of whistles tuned to 5ths, for example.
VAWT Whistle Stack
VAWT whistle stacks use vertical axis wind turbine (VAWT) foils to encourage a more periodic rotation of the whistle. The VAWT code was adapted from the work of Patrick Gaston (see the code for more details).
Whistle trees are ‘grown’ using a recursive branching algorithm. This creates a group of whistles that bench out from a central trunk. Each whistle is tuned in relation to the base whistle similar to the whistle stack.