Investigating sound-field reproduction methods as perceived by bilateral hearing aid users and normal-hearing listeners

A perceptual study was conducted to investigate the perceived accuracy of two sound-field reproduction approaches when experienced by hearing-impaired (HI) and normal-hearing (NH) listeners. The methods under test were traditional signal-independent Ambisonics reproduction and a parametric signal-dependent alternative, which were both rendered at different Ambisonic orders. The experiment was repeated in two different rooms: (1) an anechoic chamber, where the audio was delivered over an array of 44 loudspeakers; (2) an acoustically-treated listening room with a comparable setup, which may be more easily constructed within clinical settings. Ten bilateral hearing aid users, with mild to moderate symmetric hearing loss, wearing their devices, and 15 NH listeners were asked to rate the methods based upon their perceived similarity to simulated reference conditions. In the majority of cases, the results indicate that the parametric reproduction method was rated as being more similar to the reference conditions than the signal-independent alternative. This trend is evident for both groups, although the variation in responses was notably wider for the HI group. Furthermore, generally similar trends were observed between the two listening environments for the parametric method. The signal-independent approach was instead rated as being more similar to the reference in the listening room.