Ra. Lutfi et El. Oh, AUDITORY-DISCRIMINATION OF MATERIAL CHANGES IN A STRUCK-CLAMPED BAR, The Journal of the Acoustical Society of America, 102(6), 1997, pp. 3647-3656
The principles of theoretical acoustics were applied to approximately
reconstruct the sound pressure waveform at the ear as would be generat
ed by an idealized struck-clamped bar. The result is an inharmonic sum
of damped sinusoids whose individual acoustic parameters (frequency,
intensity, and decay modulus) are, for a fixed geometry and fixed driv
ing force, uniquely determined by the material composition of the bar.
In the standard 2IFC procedure, listeners were asked to discriminate
changes in material composition based on their perception of the acous
tic waveform. Listener strategies for discriminating such changes were
estimated by perturbing slightly the individual acoustic parameters f
rom trial to trial and computing correlations with the listener's resp
onse [cf. R. A. Lutfi and E. Oh, J. Acoust. Sec. Am. 95, 2963(A) (1994
)]. In general, the correlations reveal that listeners fail to make op
timal use of the information in the acoustic waveform by tending to gi
ve undue weight, for a given material change, to changes in component
frequency. In some case, the accompanying reduction in performance eff
iciency amounted to 80%. (C) 1997 Acoustical Society of America. [S000
1-4966(97)03312-2].