I was curious about Ft. Myer’s regular bugle calls, the ones that go echoing around Arlington, and I e-mailed the fort’s librarian to find out more about them. She in turn e-mailed the fort’s historian, who had the answers. Thanks much to both of them.
According to the historian, the calls are tape-recordings that military staffers broadcast over three loud speakers placed throughout the fort. With Reveille in the morning and with Retreat and To the Colors in the evening, the speakers bounce the sound around the hills and create the echo. There’s apparently a cannon blast between the two evening calls, but I’ve never heard it.