The Effect of Finite Sized Baffles on Mobile Device Personal Audio

To reduce the annoyance from the use of loudspeakers on mobile devices, previous work has investigated the use of acoustic contrast control to optimise the performance of small arrays of loudspeakers. These investigations have assumed that the baffle dimensions are negligible so that the loudspeakers are omnidirectional, which is reasonable at low frequencies; however, in practice the effect of a finite-sized baffle on the optimised performance is important at higher frequencies. This paper reports the results of using a finite-element model of a two-source array, positioned on a mobile phone sized baffle, to investigate the influence of the baffle on the predicted array performance. The baffle is shown to reduce the performance of the array at frequencies greater than around 1 kHz, but then the directivity of the individual drivers enhances performance at these higher frequencies.