Improving speech intelligibility for binaural voice transmission under disturbing noise and reverberation using virtual speaker lateralization

Abstract

Subjective speech intelligibility tests were carried out in order to investigate strategies to improve speech intelligibility in binaural voice transmission when listening from different azimuth angles under adverse listening conditions. Phonetically balanced bi-syllable meaningful words in Spanish were used as speech material. The speech signal was played back through headphones, undisturbed, and also with the addition of high levels of disturbing noise or reverberation, with a signal to noise ratio of SNR = -10 dB and a reverberation time of T60 = 10 s. Speech samples were contaminated with interaurally uncorrelated noise and interaurally correlated reverberation, which previous studies have shown the more adverse. Results show that, for speech contaminated with interaurally uncorrelated noise, intelligibility scores improve for azimuth angles around ±30° over speech intelligibility at 0°. On the other hand, for interaurally correlated reverberation, binaural speech intelligibility reduces when listening at azimuth angles around ±30°, in comparison with listening at 0° or azimuth angles around ±60°.