  Loudspeaker-based spatial audio reproduction schemes are increasingly used
for evaluating hearing aids in complex acoustic conditions. To further
establish the feasibility of this approach, this study investigated the
interaction between spatial resolution of different reproduction methods and
technical and perceptual hearing aid performance measures using computer
simulations. Three spatial audio reproduction methods -- discrete speakers,
vector base amplitude panning and higher order ambisonics -- were compared in
regular circular loudspeaker arrays with 4 to 72 channels. The influence of
reproduction method and array size on performance measures of representative
multi-microphone hearing aid algorithm classes with spatially distributed
microphones and a representative single channel noise-reduction algorithm was
analyzed. Algorithm classes differed in their way of analyzing and exploiting
spatial properties of the sound field, requiring different accuracy of sound
field reproduction. Performance measures included beam pattern analysis,
signal-to-noise ratio analysis, perceptual localization prediction, and quality
modeling. The results show performance differences and interaction effects
between reproduction method and algorithm class that may be used for guidance
when selecting the appropriate method and number of speakers for specific tasks
in hearing aid research.
