Design of a System to Measure Spatial Sound Localization Abilities

Hearing ability declines with age. Specifically, it has been shown that sound localization ability becomes increasingly unreliable. This paper describes the design of a system that simulates spatial sound sources to be presented to the user via headphones. Simulation of spatial sound sources are calculated using four increasingly complex methods; (1) Phase adjustment simulation, (2) Amplitude adjustment simulation, (3) Amplitude + Phase adjustment simulation, and (4) Head Related Transfer Function (HRTF) adjustment simulation. The preliminary validation experiment is presented in order to evaluate if the system's simulated sources presented via noise cancelling headphones is comparable to previous work using simulated sources presented via a loudspeaker array surrounding the user. Eight participants were asked to report the perceived direction of the source for each simulation method. Overall the amplitude simulation performed the best (47.5% accuracy within a ±30° window), however a high accuracy is not needed for these simulation methods to be relevant. Implementing these methods to differentiate between population groups is the main goal. A secondary repeatability experiment was done using the amplitude simulation, which suggests that the method is suitable give the ±30° window constraint. Future implementations are proposed to evaluate if the user interface and accompanying user feedback is able to identify older adults from younger adults. This may lead to a measure of decreasing hearing abilities associated the aging process.