{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,14]],"date-time":"2026-10-14T04:12:42Z","timestamp":1791951162892,"version":"4.3.4"},"reference-count":44,"publisher":"Acoustical Society of America (ASA)","issue":"3","funder":[{"DOI":"10.13039\/100000055","name":"National Institute on Deafness and Other Communication Disorders","doi-asserted-by":"publisher","award":["R15 DC014129-03A1"],"award-info":[{"award-number":["R15 DC014129-03A1"]}],"id":[{"id":"10.13039\/100000055","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["pubs.aip.org"],"crossmark-restriction":true},"short-container-title":[],"published-print":{"date-parts":[[2026,3,1]]},"abstract":"<jats:p>This paper investigates the physical significance of ear-canal wave quantities\u2014such as absorbance\u2014that are commonly measured in wideband-acoustic-immittance tests and evaluates whether these quantities uniquely characterize middle-ear function. This is explored using simulations of lumped-element and transmission-line ear canals, along with measurements in three-dimensional-printed uniform and anatomical ear canals of varying geometry, terminated by the same middle-ear simulator. The results demonstrate the following points: (1) Wave quantities computed using estimated or geometrical cross-sectional areas do not uniquely characterize the middle ear because they describe the wave interaction between ear canal and middle ear and are therefore confounded by variations in ear-canal geometry. (2) At low frequencies, the reflection of sound waves in the ear canal plays a negligible role in the middle-ear transduction mechanism because of the long sound wavelength relative to ear-canal length, and wave quantities therefore do not provide a meaningful physical characterization of middle-ear function. (3) Wave quantities computed using an invariant cross-sectional area are likely most appropriate for clinical diagnostics, as they reduce the influence of ear-canal geometry up to approximately 3\u2009kHz. However, this simplification means that wave quantities no longer characterize the reflection of sound waves in the ear canal at any frequency.<\/jats:p>","DOI":"10.1121\/10.0043164","type":"journal-article","created":{"date-parts":[[2026,3,25]],"date-time":"2026-03-25T12:04:08Z","timestamp":1774440248000},"page":"2857-2874","update-policy":"https:\/\/doi.org\/10.1063\/aip-crossmark-policy-page","source":"Crossref","is-referenced-by-count":1,"title":["Wideband acoustic immittance: Suitable quantities for assessing middle-ear status"],"prefix":"10.1121","volume":"159","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-6845-0388","authenticated-orcid":false,"given":"Kren Monrad","family":"N\u00f8rgaard","sequence":"first","affiliation":[{"name":"Interacoustics Research Unit 1 , 2800 Kongens Lyngby,","place":["Denmark"]},{"name":"Interacoustics A\/S 2 , 5500 Middelfart,","place":["Denmark"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jingxin Jessica","family":"Feng","sequence":"additional","affiliation":[{"name":"Picker Engineering Program, Smith College 3 , Northampton, Massachusetts 01063,","place":["USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3937-8145","authenticated-orcid":false,"given":"Susan E.","family":"Voss","sequence":"additional","affiliation":[{"name":"Picker Engineering Program, Smith College 3 , Northampton, Massachusetts 01063,","place":["USA"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"231","published-online":{"date-parts":[[2026,3,25]]},"reference":[{"key":"2026032508040263900_c1","doi-asserted-by":"publisher","first-page":"254","DOI":"10.1044\/2023_AJA-23-00228","article-title":"Survey of wideband acoustic immittance use by clinical audiologists","volume":"33","year":"2024","journal-title":"Am. J. Audiol."},{"key":"2026032508040263900_c2","doi-asserted-by":"crossref","first-page":"44","DOI":"10.1007\/978-3-642-50038-1_6","article-title":"Measurement of eardrum acoustic impedance","volume-title":"Peripheral Auditory Mechanisms","author":"Allen","year":"1986"},{"key":"2026032508040263900_c3","volume-title":"An Invitation to Mathematical Physics and Its History","year":"2020"},{"key":"2026032508040263900_c4","doi-asserted-by":"publisher","first-page":"108782","DOI":"10.1016\/j.heares.2023.108782","article-title":"Measurements of ear-canal geometry from high-resolution CT scans of human adult ears","volume":"434","year":"2023","journal-title":"Hear. Res."},{"key":"2026032508040263900_c5","doi-asserted-by":"publisher","first-page":"1764","DOI":"10.1121\/1.396510","article-title":"Equivalent circuits for conical waveguides","volume":"83","year":"1988","journal-title":"J. Acoust. Soc. Am."},{"key":"2026032508040263900_c6","doi-asserted-by":"publisher","first-page":"241","DOI":"10.1121\/1.390402","article-title":"Input impedance of brass musical instruments\u2014Comparison between experiment and numerical models","volume":"75","year":"1984","journal-title":"J. Acoust. Soc. Am."},{"key":"2026032508040263900_c7","doi-asserted-by":"publisher","first-page":"515","DOI":"10.1121\/1.4973618","article-title":"Compensating for ear-canal acoustics when measuring otoacoustic emissions","volume":"141","year":"2017","journal-title":"J. Acoust. Soc. Am."},{"key":"2026032508040263900_c8","doi-asserted-by":"publisher","first-page":"901","DOI":"10.1044\/1092-4388(2003\/070)","article-title":"Wideband energy reflectance measurements in adults with middle-ear disorders","volume":"46","year":"2003","journal-title":"J. Speech Lang. Hear. Res."},{"key":"2026032508040263900_c9","doi-asserted-by":"publisher","first-page":"78S","DOI":"10.1097\/AUD.0b013e31829c726b","article-title":"Consensus statement: Eriksholm Workshop on Wideband Absorbance Measures of the Middle Ear","volume":"34","year":"2013","journal-title":"Ear Hear."},{"key":"2026032508040263900_c10","article-title":"Effects of ear canal geometry on normative adult wideband acoustic immittance (WAI) measurements","year":"2024"},{"key":"2026032508040263900_c11","doi-asserted-by":"publisher","first-page":"1128","DOI":"10.1121\/1.1287024","article-title":"A noninvasive method for estimating acoustic admittance at the tympanic membrane","volume":"108","year":"2000","journal-title":"J. Acoust. Soc. Am."},{"key":"2026032508040263900_c12","unstructured":"Hudde, H. (1980). \u201cMessung der Trommelfellimpedanz des menschlichen Ohres bis 19 kHz,\u201d (\u201cMeasurement of the eardrum impedance of the human ear up to 19 kHz\u201d), Ph.D. thesis, Ruhr-Universit\u00e4t Bochum, Bochum, Germany."},{"key":"2026032508040263900_c13","doi-asserted-by":"publisher","first-page":"242","DOI":"10.1121\/1.388855","article-title":"Measurement of the eardrum impedance of human ears","volume":"73","year":"1983","journal-title":"J. Acoust. Soc. Am."},{"key":"2026032508040263900_c14","doi-asserted-by":"publisher","first-page":"3146","DOI":"10.1121\/1.3097446","article-title":"Sound fields in generally shaped curved ear canals","volume":"125","year":"2009","journal-title":"J. Acoust. Soc. Am."},{"key":"2026032508040263900_c15","volume-title":"Occluded-Ear Simulator for the Measurement of Earphones Coupled to the Ear by Means of Ear Inserts","author":"IEC","year":"2010"},{"key":"2026032508040263900_c16","doi-asserted-by":"publisher","first-page":"2849","DOI":"10.1121\/1.420340","article-title":"Otoreflectance of the cochlea and middle ear","volume":"102","year":"1997","journal-title":"J. Acoust. Soc. Am."},{"key":"2026032508040263900_c17","doi-asserted-by":"publisher","first-page":"300","DOI":"10.1121\/10.0000588","article-title":"Causality-constrained measurements of aural acoustic reflectance and reflection functions","volume":"147","year":"2020","journal-title":"J. Acoust. Soc. Am."},{"key":"2026032508040263900_c18","doi-asserted-by":"publisher","first-page":"443","DOI":"10.1097\/00003446-200010000-00009","article-title":"Identification of neonatal hearing impairment: Ear-canal measurements of acoustic admittance and reflectance in neonates","volume":"21","year":"2000","journal-title":"Ear Hear."},{"key":"2026032508040263900_c19","doi-asserted-by":"publisher","first-page":"3625","DOI":"10.1121\/1.4936946","article-title":"Procedures for ambient-pressure and tympanometric tests of aural acoustic reflectance and admittance in human infants and adults","volume":"138","year":"2015","journal-title":"J. Acoust. Soc. Am."},{"key":"2026032508040263900_c20","doi-asserted-by":"publisher","first-page":"470","DOI":"10.1121\/1.402733","article-title":"Method to measure acoustic impedance and reflection coefficient","volume":"91","year":"1992","journal-title":"J. Acoust. Soc. Am."},{"key":"2026032508040263900_c21","doi-asserted-by":"publisher","first-page":"3217","DOI":"10.1121\/1.1625931","article-title":"Energy transmittance predicts conductive hearing loss in older children and adults","volume":"114","year":"2003","journal-title":"J. Acoust. Soc. Am."},{"key":"2026032508040263900_c22","doi-asserted-by":"publisher","first-page":"977","DOI":"10.1121\/1.4927408","article-title":"Non-invasive estimation of middle-ear input impedance and efficiency","volume":"138","year":"2015","journal-title":"J. Acoust. Soc. Am."},{"key":"2026032508040263900_c23","doi-asserted-by":"publisher","first-page":"969","DOI":"10.1121\/10.0005822","article-title":"The influence of otitis media with effusion on middle-ear impedance estimated from wideband acoustic immittance measurements","volume":"150","year":"2021","journal-title":"J. Acoust. Soc. Am."},{"key":"2026032508040263900_c24","doi-asserted-by":"publisher","first-page":"171","DOI":"10.1016\/0003-682X(92)90046-U","article-title":"Fundamentals of binaural technology","volume":"36","year":"1992","journal-title":"Appl. Acoust."},{"key":"2026032508040263900_c25","first-page":"300","article-title":"Head-related transfer functions of human subjects","volume":"43","year":"1995","journal-title":"J. Audio Eng. Soc."},{"key":"2026032508040263900_c26","doi-asserted-by":"publisher","first-page":"2227","DOI":"10.1121\/10.0021313","article-title":"A reference for ear-canal absorbance based on semi-anechoic waveguides","volume":"154","year":"2023","journal-title":"J. Acoust. Soc. Am."},{"key":"2026032508040263900_c27","doi-asserted-by":"publisher","first-page":"909","DOI":"10.1121\/10.0017119","article-title":"Comments on forward pressure and other reflectance-based quantities for delivering stimuli to the ear","volume":"153","year":"2023","journal-title":"J. Acoust. Soc. Am."},{"key":"2026032508040263900_c28","doi-asserted-by":"publisher","first-page":"2334","DOI":"10.1121\/10.0001094","article-title":"Reproducing ear-canal reflectance using two measurement techniques in adult ears","volume":"147","year":"2020","journal-title":"J. Acoust. Soc. Am."},{"key":"2026032508040263900_c29","doi-asserted-by":"publisher","first-page":"634","DOI":"10.1121\/10.0009325","article-title":"A systematic study on effects of calibration-waveguide geometry and least-squares formulation on ear-probe source calibrations","volume":"151","year":"2022","journal-title":"J. Acoust. Soc. Am."},{"key":"2026032508040263900_c30","doi-asserted-by":"publisher","first-page":"2769","DOI":"10.1121\/10.0025768","article-title":"The influence of tympanic-membrane orientation on acoustic ear-canal quantities: A finite-element analysis","volume":"155","year":"2024","journal-title":"J. Acoust. Soc. Am."},{"key":"2026032508040263900_c31","doi-asserted-by":"publisher","first-page":"1350","DOI":"10.1121\/1.5123379","article-title":"A comparison of ear-canal-reflectance measurement methods in an ear simulator","volume":"146","year":"2019","journal-title":"J. Acoust. Soc. Am."},{"key":"2026032508040263900_c32","doi-asserted-by":"publisher","first-page":"1464","DOI":"10.1121\/1.5124000","article-title":"On the calculation of reflectance in non-uniform ear canals","volume":"146","year":"2019","journal-title":"J. Acoust. Soc. Am."},{"key":"2026032508040263900_c33","doi-asserted-by":"publisher","first-page":"3497","DOI":"10.1121\/1.5016808","article-title":"Compensating for evanescent modes and estimating characteristic impedance in waveguide acoustic impedance measurements","volume":"142","year":"2017","journal-title":"J. Acoust. Soc. Am."},{"key":"2026032508040263900_c34","doi-asserted-by":"publisher","first-page":"3013","DOI":"10.1121\/1.5010891","article-title":"Incorporating evanescent modes and flow losses into reference impedances in acoustic Th\u00e9venin calibration","volume":"142","year":"2017","journal-title":"J. Acoust. Soc. Am."},{"key":"2026032508040263900_c35","doi-asserted-by":"publisher","first-page":"3499","DOI":"10.1121\/1.5111340","article-title":"Compensating for oblique ear-probe insertions in ear-canal reflectance measurements","volume":"145","year":"2019","journal-title":"J. Acoust. Soc. Am."},{"key":"2026032508040263900_c36","doi-asserted-by":"publisher","first-page":"1749","DOI":"10.1121\/1.426713","article-title":"Prediction of conductive hearing loss based on acoustic ear-canal response using a multivariate clinical decision theory","volume":"105","year":"1999","journal-title":"J. Acoust. Soc. Am."},{"key":"2026032508040263900_c37","doi-asserted-by":"publisher","first-page":"1025","DOI":"10.1121\/1.386953","article-title":"Measurement of the acoustic input immittance of the human ear","volume":"70","year":"1981","journal-title":"J. Acoust. Soc. Am."},{"key":"2026032508040263900_c38","doi-asserted-by":"publisher","first-page":"3873","DOI":"10.1121\/1.3654019","article-title":"Inverse solution of ear-canal area function from reflectance","volume":"130","year":"2011","journal-title":"J. Acoust. Soc. Am."},{"key":"2026032508040263900_c39","doi-asserted-by":"publisher","first-page":"1768","DOI":"10.1121\/1.4894787","article-title":"Comparison of nine methods to estimate ear-canal stimulus levels","volume":"136","year":"2014","journal-title":"J. Acoust. Soc. Am."},{"key":"2026032508040263900_c40","doi-asserted-by":"publisher","first-page":"766","DOI":"10.1121\/1.388257","article-title":"Estimation of acoustical energy reflectance at the eardrum from measurements of pressure distribution in the human ear canal","volume":"72","year":"1982","journal-title":"J. Acoust. Soc. Am."},{"key":"2026032508040263900_c41","doi-asserted-by":"publisher","first-page":"372","DOI":"10.1121\/1.408329","article-title":"Measurement of acoustic impedance and reflectance in the human ear canal","volume":"95","year":"1994","journal-title":"J. Acoust. Soc. Am."},{"key":"2026032508040263900_c42","doi-asserted-by":"publisher","DOI":"10.1177\/23312165251345572","article-title":"Comprehensive measurements and analyses of ear canal geometry from late infancy through late adulthood: Age-related variations and implications for basic science and audiological measurements","year":"2025","journal-title":"Trends Hear."},{"key":"2026032508040263900_c43","doi-asserted-by":"publisher","first-page":"695","DOI":"10.1121\/10.0024495","article-title":"Effect of curvature on sound propagation in the ear canal","volume":"155","year":"2024","journal-title":"J. Acoust. Soc. Am."},{"key":"2026032508040263900_c44","doi-asserted-by":"publisher","DOI":"10.1080\/14992027.2025.2590546","article-title":"Age effect on wideband absorbance in people with normal middle ear function: A systematic review","year":"2025","journal-title":"Int. J. Audiol."}],"container-title":["The Journal of the Acoustical Society of America"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/pubs.aip.org\/asa\/jasa\/article-pdf\/159\/3\/2857\/20953243\/2857_1_10.0043164.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/pubs.aip.org\/asa\/jasa\/article-pdf\/159\/3\/2857\/20953243\/2857_1_10.0043164.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,3,25]],"date-time":"2026-03-25T12:04:10Z","timestamp":1774440250000},"score":1,"resource":{"primary":{"URL":"https:\/\/pubs.aip.org\/jasa\/article\/159\/3\/2857\/3384776\/Wideband-acoustic-immittance-Suitable-quantities"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,3,1]]},"references-count":44,"journal-issue":{"issue":"3","published-print":{"date-parts":[[2026,3,1]]}},"URL":"https:\/\/doi.org\/10.1121\/10.0043164","relation":{},"ISSN":["1520-8524"],"issn-type":[{"value":"1520-8524","type":"electronic"}],"subject":[],"published-other":{"date-parts":[[2026,3]]},"published":{"date-parts":[[2026,3,1]]}}}