Hearing is a function of the acoustic signal and the properties of the environment that structure the sound. To better understand how hearing is affected by structural properties, the current research investigated the impact of football helmets for hearing. Speech signals were broadcast at three angles of incidence (0°, 45°, or 90°) to an artificial dummyhead recording device wearing a football helmet (experimental condition) or without the helmet (control condition) to make binaural recordings using condenser microphones positioned at the location of the tympanic membrane. Acoustic analyses revealed that the helmet caused frequency-specific changes to an auditory signal, including both positive and negative interference that varied in relationship to the angle of incidence. Behavioral studies showed that while; in general, the football helmet made hearing speech more difficult, the magnitude of the decrement was a function of the amount of spectral change induced in the speech signal. Results are discussed in terms of the implications of an ecological approach to hearing and the design of helmets.