The MBSTOI Binaural Intelligibility Metric Using a Close-Talking Microphone Reference

Intelligibility metrics are a fast way to determine how comprehensible a target signal is in a noisy situation. Most metrics however rely on having a clean reference signal for computation and are not adapted to live recordings. In this paper the deep correlation modified binaural short time objective intelligibility metric (Dcor-MBSTOI) is evaluated with a single-channel close-talking microphone signal as the reference. This reference signal inevitably contains some background noise and crosstalk from non-target sources. It is found that intelligibility is overestimated when using the close-talking microphone signal directly but that this overestimation can be eliminated by applying speech enhancement to the reference signal.