Spatial release from masking is traditionally measured with speech in front. The effect of head-orientation with respect to the speech direction has rarely been studied. Speech-reception thresholds (SRTs) were measured for eight head orientations and four spatial configurations. Benefits of head orientation away from the speech source of up to 8 dB were measured. These correlated with predictions of a model based on better-ear listening and binaural unmasking (r = 0.96). Use of spontaneous head orientations was measured when listeners attended to long speech clips of gradually diminishing speech-to-noise ratio in a sound-deadened room. Speech was presented from the loudspeaker that initially faced the listener and noise from one of four other locations. In an undirected paradigm, listeners spontaneously turned their heads away from the speech in 56% of trials. When instructed to rotate their heads in the diminishing speech-to-noise ratio, all listeners turned away from the speech and reached head orientations associated with lower SRTs. Head orientation may prove valuable for hearing-impaired listeners.

In optimal conditions, the benefit of bilateral implantation to speech intelligibility in noise can be much larger than has previously been reported. This benefit is thus considerably larger than reported benefits of summation or squelch and is robust in reverberation when the interfering source is close.

In cochlear implant simulation with vocoders, narrow-band carriers deliver the envelopes from each analysis band to the cochlear positions of the simulated electrodes. However, this approach does not faithfully represent the continuous nature of the spiral ganglion. The proposed “SPIRAL” vocoder simulates current spread by mixing all envelopes across many tonal carriers. SPIRAL demonstrated that the classic finding of reduced speech-intelligibility benefit with additional electrodes could be due to current spread. SPIRAL produced lower speech reception thresholds than an equivalent noise vocoder. These thresholds are stable for between 20 and 160 carriers.

Cochlear implant (CI) users suffer from elevated speech-reception thresholds and may rely on lip reading. Traditional measures of spatial release from masking quantify speech-reception-threshold improvement with azimuthal separation of target speaker and interferers and with the listener facing the target speaker. Substantial benefits of orienting the head away from the target speaker were predicted by a model of spatial release from masking. Audio-only and audio-visual speech-reception thresholds in normal-hearing (NH) listeners and bilateral and unilateral CI users confirmed model predictions of this head-orientation benefit. The benefit ranged 2–5 dB for a modest 30° orientation that did not affect the lip-reading benefit. NH listeners' and CI users' lip-reading benefit measured 3 and 5 dB, respectively. A head-orientation benefit of ∼2 dB was also both predicted and observed in NH listeners in realistic simulations of a restaurant listening environment. Exploiting the benefit of head orientation is thus a robust hearing tactic that would benefit both NH listeners and CI users in noisy listening conditions.

Turning an ear toward the talker can enhance spatial release from masking. Here, with their head free, listeners attended to speech at a gradually diminishing signal-to-noise ratio and with the noise source azimuthally separated from the speech source by 180° or 90°. Young normal-hearing adult listeners spontaneously turned an ear toward the speech source in 64% of audio-only trials, but a visible talker’s face or cochlear implant (CI) use significantly reduced this head-turn behavior. All listener groups made more head movements once instructed to explore the potential benefit of head turns and followed the speech to lower signal-to-noise ratios. Unilateral CI users improved the most. In a virtual restaurant simulation with nine interfering noises or voices, hearing-impaired listeners and simulated bilateral CI users typically obtained a 1 to 3 dB head-orientation benefit from a 30° head turn away from the talker. In diffuse interference environments, the advice to U.K. CI users from many CI professionals and the communication guidance available on the Internet most often advise the CI user to face the talker head on. However, CI users would benefit from guidelines that recommend they look sidelong at the talker with their better hearing or implanted ear oriented toward the talker.