Have you ever wondered why people say musician’s earplugs sound so much more natural than traditional hearing protection such as foam earplugs or earmuffs?
The answer is that they artificially restore the natural resonance of the open ear canal that is otherwise spoiled when the ear is obstructed by an earplug or earmuff.
That’s right, your ear canal resonates optimally at a particular frequency, just like an empty bottle does if you blow into it! The resonance of the average adult ear canal is typically around 2700 Hz (whereas a coke bottle has a much lower resonant frequency – around 150 Hz).
Sound is given a boost around this frequency when it enters the ear. This happens to be a good frequency to get a boost at, as 2700 Hz is an important frequency for speech clarity and understanding. When we occlude the ear, we destroy this resonance and speech (as well as music) sounds muffled and unnatural.
Musician’s earplugs use an acoustic filter to restore the resonance of the open ear canal while providing relatively flat attenuation. As a result, speech and music sound much more natural. For these reasons, musician’s earplugs are used by a wide variety of occupations (not just musicians).
The graph below exemplifies the ideal response from a musician’s earplug. The resonance around 2700 Hz mimics that of the open ear and the attenuation across frequencies is even.