Auditory model-based estimation of the effect of head-worn devices on frontal horizontal localisation

Auditory localisation accuracy may be degraded when a head-worn device (HWD), such as a helmet or hearing protector, is used. A computational method is proposed in this study for estimating how horizontal plane localisation is impaired by a HWD through distortions of interaural cues. Head-related impulse responses (HRIRs) of different HWDs were measured with a KEMAR and a binaural auditory model was used to compute interaural cues from HRIR-convolved noise bursts. A shallow neural network (NN) was trained with data from a subjective listening experiment, where horizontal plane localisation was assessed while wearing different HWDs. Interaural cues were used as features to estimate perceived direction and position uncertainty (standard deviation) of a sound source in the horizontal plane with the NN. The NN predicted the position uncertainty of localisation among subjects for a given HWD with an average estimation error of 1°. The obtained results suggest that it is possible to predict the degradation of localisation ability for specific HWDs in the frontal horizontal plane using the method.

The development of linguistic stimuli for the Swedish Situated Phoneme test

The speech perception ability of people with hearing loss can be efficiently measured using phonemic-level scoring. We aimed to develop linguistic stimuli suitable for a closed-set phonemic discrimination test in the Swedish language called the Situated Phoneme (SiP) test. The SiP test stimuli that we developed consisted of real monosyllabic words with minimal phonemic contrast, realised by phonetically similar phones. The lexical and sublexical factors of word frequency, phonological neighbourhood density, phonotactic probability, and orthographic transparency were similar between all contrasting words. Each test word was recorded five times by two different speakers, including one male and one female. The accuracy of the test-word recordings was evaluated by 28 normal-hearing subjects in a listening experiment with a silent background using a closed-set design. With a few exceptions, all test words could be correctly discriminated. We discuss the results in terms of content- and construct-validity implications for the Swedish SiP test.

Mishearing as a Side Effect of Rational Language Comprehension in Noise

Language comprehension in noise can sometimes lead to mishearing, due to the noise disrupting the speech signal. Some of the difficulties in dealing with the noisy signal can be alleviated by drawing on the context – indeed, top-down predictability has shown to facilitate speech comprehension in noise. Previous studies have furthermore shown that strong reliance on the top-down predictions can lead to increased rates of mishearing, especially in older adults, which are attributed to general deficits in cognitive control in older adults. We here propose that the observed mishearing may be a simple consequence of rational language processing in noise. It should not be related to failure on the side of the older comprehenders, but instead would be predicted by rational processing accounts. To test this hypothesis, we extend earlier studies by running an online listening experiment with younger and older adults, carefully controlling the target and direct competitor in our stimuli. We show that mishearing is directly related to the perceptibility of the signal. We furthermore add an analysis of wrong responses, which shows that results are at odds with the idea that participants overly strongly rely on context in this task, as most false answers are indeed close to the speech signal, and not to the semantics of the context.

Not all wh-dependencies are created equal: processing of multiple wh-questions in Romanian children and adults

The aim of this study was to examine the acquisition and processing of multiple who- and which-questions in Romanian that display ordering constraints and involve exhaustivity. Toward that aim, typically developing Romanian children (mean age 8.3) and adults participated in a self-paced listening experiment that simultaneously investigated online processing and offline comprehension of multiple wh-questions. The study manipulated the type of wh-phrase (who/which) and the order in which these elements appear (subject–object [SO]/object–subject [OS]). The response to the comprehension question could address the issue of exhaustivity because we measured whether participants used an exhaustive or a non-exhaustive response. Our findings reveal that both children and adults slow down when processing who- as compared to which-phrases, but only adults show an online sensitivity to ordering constraints in who-questions. Accuracy is higher with multiple who- than which-questions. The latter pose more difficulties for comprehension, particularly in the OS order. We relate this to intervention effects similar to those proposed for single which-questions. The lack of intervention effects in terms of reaction times indicates that these effects occur at a later stage, after participants have heard the whole sentence and when they interpret its meaning.

The Deployment of the Seismometer to Investigate Ice and Ocean Structure (SIIOS) in Northwest Greenland: An Analog Experiment for Icy Ocean World Seismic Deployments

In anticipation of future spacecraft missions to icy ocean worlds, the Seismometer to Investigate Ice and Ocean Structure (SIIOS) was funded by National Aeronautics and Space Administration, to prepare for seismologic investigations of these worlds. During the summer of 2018, the SIIOS team deployed a seismic experiment on the Greenland ice sheet situated, approximately, 80 km north of Qaanaaq, Greenland. The seismometers deployed included one Trillium 120 s Posthole (TPH) broadband seismometer, 13 Silicon Audio flight-candidate seismometers, and five Sercel L28 4.5 Hz geophones. Seismometers were buried 1 m deep in the firn in a cross-shaped array centered on a collocated TPH and Silicon Audio instrument. One part of the array consisted of Silicon Audio and Sercel geophones situated 1 m from the center of the array in the ordinal directions. A second set of four Silicon Audio instruments was situated 1 km from the center of the array in the cardinal directions. A mock-lander spacecraft was placed at the array center and instrumented with four Silicon Audio seismometers. We performed an active-source experiment and a passive-listening experiment that lasted for, approximately, 12 days. The active–source experiment consisted of 9–12 sledgehammer strikes to an aluminum plate at 10 separate locations up to 100 m from the array center. The passive experiment recorded the ice-sheet ambient background noise, as well as local and regional events. Both datasets will be used to quantify differences in spacecraft instrumentation deployment strategies, and for evaluating science capabilities for single-station and small-aperture seismic arrays in future geophysical missions. Our initial results indicate that the flight-candidate seismometer performs comparably to the TPH at frequencies above 0.1 Hz and that instruments coupled to the mock-lander perform comparably to ground-based instrumentation in the frequency band of 0.1–10 Hz. For future icy ocean world missions, a deck-coupled seismometer would perform similarly to a ground-based deployment across the most frequency bands.

Implementation of an Online Auditory Attention Detection Model with Electroencephalography in a Dichotomous Listening Experiment

Auditory attention detection (AAD) is the tracking of a sound source to which a listener is attending based on neural signals. Despite expectation for the applicability of AAD in real-life, most AAD research has been conducted on recorded electroencephalograms (EEGs), which is far from online implementation. In the present study, we attempted to propose an online AAD model and to implement it on a streaming EEG. The proposed model was devised by introducing a sliding window into the linear decoder model and was simulated using two datasets obtained from separate experiments to evaluate the feasibility. After simulation, the online model was constructed and evaluated based on the streaming EEG of an individual, acquired during a dichotomous listening experiment. Our model was able to detect the transient direction of a participant’s attention on the order of one second during the experiment and showed up to 70% average detection accuracy. We expect that the proposed online model could be applied to develop adaptive hearing aids or neurofeedback training for auditory attention and speech perception.

Uncertainty in tuning evaluation with low-register complex tones of orchestra instruments

The relationship between perceived pitch and harmonic spectrum in complex tones is ambiguous. In this study, 31 professional orchestra musicians participated in a listening experiment where they adjusted the pitch of complex low-register successively presented tones to unison. Tones ranged from A0 to A2 (27.6–110 Hz) and were derived from acoustic instrument samples at three different dynamic levels. Four orchestra instruments were chosen as sources of the stimuli; double bass, bass tuba, contrabassoon, and contrabass clarinet. In addition, a sawtooth tone with 13 harmonics was included as a synthetic reference stimulus. The deviation of subjects’ tuning adjustments from unison tuning was greatest for the lowest tones, but remained unexpectedly high also for higher tones, even though all participants had long experience in accurate tuning. Preceding studies have proposed spectral centroid and Terhardt’s virtual pitch theory as useful predictors of the influence of the envelope of a harmonic spectrum on the perceived pitch. However, neither of these concepts were supported by our results. According to the principal component analysis of spectral differences between the presented tone pairs, the contrabass clarinet-type spectrum, where every second harmonic is attenuated, lowered the perceived pitch of a tone compared with tones with the same fundamental frequency but a different spectral envelope. In summary, the pitches of the stimuli were perceived as undefined and highly dependent on the listener, spectrum, and dynamic level. Despite their high professional level, the subjects did not perceive a common, unambiguous pitch of any of the stimuli. The contrabass clarinet-type spectrum lowered the perceived pitch.

Precedence effect for specular and diffuse reflections

Studies on the precedence effect are typically conducted by presenting two identical sounds simulating direct sound and specular reflection. However, when a sound is reflected from irregular surface, it is redirect into many directions resulting in directional and temporal diffusion. This contribution introduces a simulation of Lambertian diffusing reflections. The perceptual influences of diffusion are studied in a listening experiment; echo thresholds and masked thresholds of specular and diffuse reflections are measured. Results show that diffusion makes the reflections more easily detectable than specular reflections of the same total energy. Indications are found that this mainly due to temporal diffusion, while the directional diffusion has little effect. Accordingly, the modeling of the echo thresholds is achieved by a temporal alignment of the experimental data based on the energy centroid of reflection responses. For the modeling of masked threshold the temporal masking pattern for forward masking is taken into account.