Subject: Re: Air to bone transmission characteristics From: Mike Ravicz <mer(at)EPL.MEEI.HARVARD.EDU> Date: Fri, 6 Dec 2002 16:08:15 -0500>...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(at)epl.meei.harvard.edu "The ears are the vestibule of the soul." - Zippy