Re: Air to bone transmission characteristics

[Mike Ravicz <mer@xxxxxxxxxxxxxxxxxxxx>]

>...transmission of sound from air to bone.

Elliott Berger has done quite a bit of work on this recently, and Stefan
Stenfelt and we have looked it some as well.  Our recent paper [J Acoust
Soc Am 109: 216-231 (2001)] includes several useful references, including
Berger's "Laboratory attenuation of earmuffs and earplugs both singly and
in combination" [Am Ind Hyg Assoc J 44: 312-329 (1983)], Schroeter and
Poesselt [J Acoust Soc Am 80: 505-527 (1986)], and Khanna et al. [J Acoust
Soc Am 60: 139-154 (1976)].  Berger had a paper Wed. at the ASA conference
[3aNS4, p. 2294] that I believe touches on these issues.  You may find
Stenfelt's recent paper [J Acoust Soc Am 111: 947-959 (2002)] useful.  The
military has been quite interested in sound transmission as well.

>I have read somewhere that the approximate difference in HL
>between air and bone conducted hearing is about 40 dB.
>Is this any where near the truth?

Pretty close - the difference is frequency dependent, and the minimum is
38-40 dB near 2 kHz.

Mike Ravicz, Eaton-Peabody Lab., Mass. Eye & Ear Inf., Boston MA 02114 USA
+1 (617) 573-5591/3747; FAX +1 (617) 720-4408; mer@epl.meei.harvard.edu
"The ears are the vestibule of the soul." - Zippy