THE INVERSE PROBLEM SOLVED FOR A 3-DIMENSIONAL MODEL OF THE COCHLEA .2. APPLICATION TO EXPERIMENTAL-DATA SETS

With ''classical'' nonactive models of the cochlea it is impossible to simulate the degree of frequency selectivity that is revealed by mode rn mechanical measurements of the motion of the basilar membrane (BM). Locally active models have been proposed to alleviate this problem, b ut it remains uncertain whether the actual cochlea is active in this s ense. In the first paper of this series [E. de Beer, J. Acoust. Soc. A m. 98, 896-903 (1995)], the ''inverse'' problem is solved for a (class ical) three-dimensional model and a procedure is developed for recover ing the BM impedance needed to simulate a given BM response function. It was found that the results of this procedure will be more accurate in the region of the response peak than in the more basal region of th e model. In the present paper the same procedure is applied to data of recent mechanical experiments. For the peak region the outcome is une quivocal: Recent measurement results can only be simulated by the clas sical model when it is made locally active. Resynthesis of the model r esponse, on the basis of the recovered BM impedance, confirms the vali dity of the method in the peak region and strengthens this conclusion. (C) 1995 Acoustical Society of America.