Jg. Desloge et al., MICROPHONE-ARRAY HEARING-AIDS WITH BINAURAL OUTPUT .1. FIXED-PROCESSING SYSTEMS, IEEE transactions on speech and audio processing, 5(6), 1997, pp. 529-542
This work is aimed at developing a design for the use of a microphone
array with binaural hearing aids, The goal of such a hearing aid is to
provide both the spatial-filtering benefits of the array and the natu
ral benefits to sound localization and speech intelligibility that acc
rue from binaural listening, The present study examines two types of d
esigns for fixed-processing systems: one in which independent arrays p
rovide outputs to the two ears, and another in which the binaural outp
uts are derived from a single array, For the latter, various methods a
re used to merge array processing with binaural listening, In one appr
oach, filters are designed to satisfy a frequency-dependent trade betw
een directionality and binaural cue fidelity, In another, the micropho
ne signals are filtered into low-and high-frequency components with th
e lowpass signals providing binaural cues and the highpass signal bein
g the single output of the array processor, Acoustic and behavioral me
asurements were made in an anechoic chamber and in a moderately reverb
erant room to evaluate example systems, Theoretical performance was ca
lculated for model arrays mounted on an idealized spherical head, Resu
lts show that both single-and dual-array systems provided target-intel
ligibility enhancements (2-4 dB improvements in speech reception thres
hold) relative to binaural cardioid microphones, In addition, the bina
ural-output systems provided cues that assist in sound localization, w
ith resulting performance depending directly upon the cue fidelity, Fi
nally, the sphere-based calculations accurately reflected the major fe
atures of the actual head-mounted array results, both in terms of dire
ctional sensitivity and output binaural cues.