Building the Flight 93 Memorial’s Massive Chime Tower

Using musical tuning theory, the team identified distinct tones for each chime, so that, when the wind strikes, the chimes will create a “conversation” of 40 unique voices. This meant understanding the wind direction and speed at the site, and how this would affect the sound--to figure it out, the team made recordings of chime mock-ups, used computational fluid dynamic modeling to look at potential tower shapes, tested chime configurations via acoustic simulations and used a wind tunnel to simulate conditions at the site. In winter, the wind can drive in at speeds up to 40 miles an hour, while other times of year bring much milder conditions. Murdoch and his team needed to test them all.