The Tower of Voices is a 93-feet tall musical instrument near the entrance to the Flight 93 National Memorial, a national park located where United Flight 93 crashed on September 11, 2001. The tower holds 40 wind chimes that commemorate the heroic action of 40 passengers and crewmembers onboard the plane, as a living memorial in sound to remember the 40 through their ongoing voices.
The tower cradles the chimes in a circular form that opens towards an elevated public plaza. Eight precast concrete columns with branch connectors recall the trunk and branch structure of trees in the Hemlock grove at the crash site. Openings between the structural elements allow wind to pass through to activate the chime assemblies with aluminum tubes of various lengths tuned to different frequencies.
The design team included a musician, chimes artist, acoustical engineer, wind consultant and sail designer. The scale and complexity of 40 chimes, with the variability of wind directions and velocities, required an interactive process of testing and simulation using musical tuning theory, chime mock-ups, computational fluid dynamic modeling, wind tunnel testing and digital acoustic lab simulation.
