  The processing of low-frequency interaural time differences is found to be
problematic among hearing-impaired people. The current generation of
beamformers does not consider this deficiency. In an attempt to tackle this
issue, we propose to replace the inaudible interaural time differences in the
low-frequency region with the interaural level differences. In addition, a
beamformer is introduced and analyzed, which enhances the low-frequency
interaural level differences of the sound sources using a near-field
transformation. The proposed beamforming problem is relaxed to a convex problem
using semi-definite relaxation. The instrumental analysis suggests that the
low-frequency interaural level differences are enhanced without hindering the
provided intelligibility. A psychoacoustic localization test is done using a
listening experiment, which suggests that the replacement of time differences
into level differences improves the localization performance of normal-hearing
listeners for an anechoic scene but not for a reverberant scene.
