Engineers investigating “listener fatigue"-- the discomfort and pain some people experience while using in-ear headphones, hearing aids, and other devices that seal the ear canal from external sound -- have found not only what they believe is the cause, but also a potential solution. In two separate papers and a presentation at the 130th Audio Engineering Society convention in London on May 14th, 2011, Stephen Ambrose, Robert Schulein and Samuel Gido of Asius Technologies of Longmont, Colo., describe how sealing a speaker in the ear canal dramatically boosts sound pressures and how a modified ear-tip can help alleviate, or even eliminate, that effect.
