Why do bone conduction hearing aids have extended frequency range beyond 4 KHz?
What about distortion? The simple answer is, because they can. It is easy to consider Bone Conduction and Air Conduction transmission of sound as being equivalent from a measurement perspective. Air Conduction transmission occurs in the acoustic domain and if one reviews specification of output of an amplifying device via the acoustic domain, the reference is 20 dA Pa and this is referred to as dB SPL. In the case of a Bone Conduction transmission, the energy is transferred as vibration to the skull. The reference standard here is one micro Newton. Coupling of bone conduction transducers can be via a transcutaneous pathway (through the skin) or via direct bone conduction at a point source (Like an implanted Baha fixture and skin protruding abutment). This direct bone conduction pathway allows for more efficient transmission of vibrational energy to the cochlea via a transcranial pathway. The frequency response and resonance peaks for a Bone Conduction transducer look very different fro
