Chasin stresses that increased headroom isn’t just important for professional musicians. It’s for anyone who wants to listen to music. A person’s own speech can also cause distortion if volume levels are too high. With current hearing aids, one way to combat this distortion is to turn down the volume on the input sound, like a stereo or television, and turn up the volume of the hearing aid. This effectively allows a hearing aid user to “duck under” the headroom bridge and avoid the distortion. But it doesn’t give the most natural or comfortable sound.
Another solution to the problem includes creating microphones that are less sensitive to lower frequency sounds, which fools the recorder into thinking it’s receiving a signal that’s within its operating range. But again, this solution means a more artificial and less transparent sound.
No hearing aid can claim a limitless ceiling, but a new generation of digital hearing aids comes pretty close. These devices effectively raise the level of that “low-hanging bridge” and create increased headroom and a more transparent sound. These hearing aids take the 95 dB limit of modern hearing aids and shift it up to 111 dB SPL, a limit that can provide clear sound in almost any environment.
* Stach, Brad A. Comprehensive Dictionary of Audiology, Illustrated. Clifton Park, NY: Thomson/Delmar Learning, 2003. Print.