F-15 acoustic testing
The sun rises on the microphone array used to record audio of F-15EX Eagle II’s engines during a ground test Oct. 26 at Eglin Air Force Base, Fla. The aircraft underwent various ground and flight acoustic testing to create a baseline noise level for use by the Department of Defense. This was the first time this type of in-depth digital acoustic sound testing was done on any F-15 model. (U.S. Air Force photo/Samuel King Jr.)