The binaural performance of a cross-talk cancellation system with matched or mismatched setup and playback acoustics
Scale diagram of the six-loudspeaker, OSD system. The loudspeakers were used for frequencies above , the loudspeakers between 500 and , and the loudspeakers below .
Schematic illustration of each step involved in the acoustic cross-talk cancellation system. The first step (the cross-talk cancellation processing) was performed on a personal computer while the second step (cross-over filters) was performed on a separate digital-signal processing board; note the D/A and A/D converters between them. The final step was the loudspeaker presentation of the signals to an acoustic manikin, acting as the listener, with a subsequent off-line analysis of the actual signals received at its ears.
The left-loudspeaker-to-left-microphone impulse response, measured using the MLS method in the cross-talk cancellation system. The direct sound is marked, along with two putative reflections, which were removed in subsequent modifications.
The top panel shows the magnitude spectra of the signals delivered to the microphones of the manikin by the cross-talk cancellation system. The right-ear target was a white noise, while the left ear target was silence. The bottom panel shows the amount of cross-talk cancellation achieved, which was defined as the difference in those magnitude spectra.
A scale diagram of the modified acoustic system, using two loudspeakers at (cf. Fig. 1), and the amount of cross-talk cancellation it gave (cf. Fig. 4).
Schematic illustration of each step involved in the computational simulations of cross-talk cancellation. The steps follow the acoustic system (Fig. 2), except that the loudspeaker presentation is simulated by a set of digital convolution and summations. The illustration represents simulations C, D, and E (Table I), as the digital crossover filters are not shown; simulations A and B included them.
The results of the five computational simulations of cross-talk cancellation. The parameters of each simulation are reported in Table I. The bold lines in each panel show the amount of cross-talk cancellation predicted by the simulations, and the faint lines show the corresponding acoustical measurements.
The magnitude spectra of the signals at the microphones of the manikin calculated from the computational simulation. The top panel shows the results for a matched-HRIR system, the bottom panel for a mismatched-HRIR system.
The amounts of cross-talk cancellation calculated from the computational simulation, for each of the 7 matched-HRIR systems (top panel) and each of the 42 mismatched-HRIR systems (bottom panel). The values of wideband cancellation for each system are reported in Table II.
The binaural performance of the computational simulation of cross-talk cancellation, calculated for a matched-HRIR system (left panel) and two mismatched-HRIR systems (middle and right panels). Each panel shows the ongoing ITD (ordinate) and ILD (abscissa) delivered by the simulation for a large set of combinations of target ITD and ILDs (parameters); the lines join points with the same target ILD. The analysis was run at an auditory-filter frequency of .
The results of the ongoing-ITD and ongoing-ILD analyses of the computational simulation as a function of auditory-filter frequency. Each point plots the mean across all 42 mismatched-HRIR systems (the error bars show the standard deviations). For the top-left and bottom-left panels, the target ITD/ILD was ; for the top-right and bottom-right panels, the target were . The few mismatched-HRIR systems that gave exceptional ITDs (taken as being on the wrong side) are plotted as open circles.
The binaural performance of the computational simulations for the envelope ITD and ILD at . The format is the same as Fig. 10.
The results of the envelope-ITD and envelope-ILD analyses of the computational simulation as a function of auditory-filter frequency. Each point plots the mean across all 42 mismatched-HRIR systems (the error bars show the standard deviations). The six panels are for target ITD/ILDs of (top left and bottom left), (top middle and bottom middle), and target (top right and bottom right).
Summary of the computational simulations used in validating the computational model. The sampling rate was and so the duration impulse responses corresponded to 128 points, and the responses to 731 points.
The values of simulated wideband cancellation for each of the 49 combinations of listener in the AUDIS database. The seven matched-HRIR conditions are along the main diagonal; the others are the 42 mismatched-HRIR conditions. The row means and column means (both underlined) are for the mismatched conditions only. Also shown are the values when the HRIRs were taken from Gardner and Martin’s (1995) database for the KEMAR manikin.
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