The Effect of Spatially Separated Sound Sources on Speech Intelligibility

1969 ◽  
Vol 12 (1) ◽  
pp. 5-38 ◽  
Author(s):  
Donald D. Dirks ◽  
Richard H. Wilson
Keyword(s):  
Speech Intelligibility ◽  
Rank Order ◽  
Interaural Time Difference ◽  
Sound Field ◽  
Spatial Separation ◽  
Spatial Location ◽  
Time Difference ◽  
Noise Sources ◽  
Sound Sources ◽  
Interaural Time Differences

A series of five experiments was conducted to investigate the effects of spatial separation of speakers on the intelligibility of spondaic and PB words in noise and the identification of synthetic sentences in noise and competing message. Conditions in which the spatial location of the speakers produced interaural time differences ranked highest in intelligibility. The rank order of other conditions was dependent on the S/N ratio at the monaural near ear. Separations of only 10° between the speech and noise sources resulted in measurable changes in intelligibility. The binaural intelligibility scores were enhanced substantially over the monaural near ear results during conditions where an interaural time difference was present. This result was observed more effectively when spondaic words or sentences were used rather than PB words. The implications of this result were related to the interaural time difference and the frequency range of the critical information in the primary message. Although the initial experiments were facilitated by recording through an artificial head, almost identical results were obtained in the final experiment when subjects were tested in the sound field.

Spatial Stimulus Cue Information Supplying Auditory Saltation

Perception ◽  
10.1068/p3293 ◽  
2002 ◽  
Vol 31 (7) ◽  
pp. 875-885 ◽  
Author(s):  
Dennis P Phillips ◽  
Susan E Hall ◽  
Susan E Boehnke ◽  
Leanna E D Rutherford
Keyword(s):  
Spatial Perception ◽  
Interaural Time Difference ◽  
Free Field ◽  
Spatial Location ◽  
Interaural Level Difference ◽  
Sound Sources ◽  
Interaural Time Differences ◽  
Spatial Stimulus ◽  
Click Train ◽  
Interaural Level Differences

Auditory saltation is a misperception of the spatial location of repetitive, transient stimuli. It arises when clicks at one location are followed in perfect temporal cadence by identical clicks at a second location. This report describes two psychophysical experiments designed to examine the sensitivity of auditory saltation to different stimulus cues for auditory spatial perception. Experiment 1 was a dichotic study in which six different six-click train stimuli were used to generate the saltation effect. Clicks lateralised by using interaural time differences and clicks lateralised by using interaural level differences produced equivalent saltation effects, confirming an earlier finding. Switching the stimulus cue from an interaural time difference to an interaural level difference (or the reverse) in mid train was inconsequential to the saltation illusion. Experiment 2 was a free-field study in which subjects rated the illusory motion generated by clicks emitted from two sound sources symmetrically disposed around the interaural axis, ie on the same cone of confusion in the auditory hemifield opposite one ear. Stimuli in such positions produce spatial location judgments that are based more heavily on monaural spectral information than on binaural computations. The free-field stimuli produced robust saltation. The data from both experiments are consistent with the view that auditory saltation can emerge from spatial processing, irrespective of the stimulus cue information used to determine click laterality or location.

scholarly journals Linear summation in the barn owl's brainstem underlies responses to interaural time differences

2013 ◽  
Vol 110 (1) ◽  
pp. 117-130 ◽  
Author(s):  
Paula T. Kuokkanen ◽  
Go Ashida ◽  
Catherine E. Carr ◽  
Hermann Wagner ◽  
Richard Kempter
Keyword(s):  
Interaural Time Difference ◽  
Field Potential ◽  
Time Difference ◽  
Linear Summation ◽  
Interaural Time Differences ◽  
Synaptic Potentials ◽  
Binaural Stimulation ◽  
Nonlinear Responses ◽  
Model Predictions ◽  
Primary Origin

The neurophonic potential is a synchronized frequency-following extracellular field potential that can be recorded in the nucleus laminaris (NL) in the brainstem of the barn owl. Putative generators of the neurophonic are the afferent axons from the nucleus magnocellularis, synapses onto NL neurons, and spikes of NL neurons. The outputs of NL, i.e., action potentials of NL neurons, are only weakly represented in the neurophonic. Instead, the inputs to NL, i.e., afferent axons and their synaptic potentials, are the predominant origin of the neurophonic (Kuokkanen PT, Wagner H, Ashida G, Carr CE, Kempter R. J Neurophysiol 104: 2274–2290, 2010). Thus in NL the monaural inputs from the two brain sides converge and create a binaural neurophonic. If these monaural inputs contribute independently to the extracellular field, the response to binaural stimulation can be predicted from the sum of the responses to ipsi- and contralateral stimulation. We found that a linear summation model explains the dependence of the responses on interaural time difference as measured experimentally with binaural stimulation. The fit between model predictions and data was excellent, even without taking into account the nonlinear responses of NL coincidence detector neurons, although their firing rate and synchrony strongly depend on the interaural time difference. These results are consistent with the view that the afferent axons and their synaptic potentials in NL are the primary origin of the neurophonic.

Tuning to Interaural Time Difference and Frequency Differs Between the Auditory Arcopallium and the External Nucleus of the Inferior Colliculus

2009 ◽  
Vol 101 (5) ◽  
pp. 2348-2361 ◽  
Author(s):  
Katrin Vonderschen ◽  
Hermann Wagner
Keyword(s):  
Inferior Colliculus ◽  
Tuning Curve ◽  
Interaural Time Difference ◽  
Low Frequency ◽  
Steep Slope ◽  
Time Difference ◽  
Interaural Time Differences ◽  
Tuning Curves ◽  
Barn Owls ◽  
Zero Time

Barn owls process sound-localization information in two parallel pathways, the midbrain and the forebrain pathway. Exctracellular recordings of neural responses to auditory stimuli from far advanced stations of these pathways, the auditory arcopallium in the forebrain and the external nucleus of the inferior colliculus in the midbrain, demonstrated that the representations of interaural time difference and frequency in the forebrain pathway differ from those in the midbrain pathway. Specifically, low-frequency representation was conserved in the forebrain pathway, while it was lost in the midbrain pathway. Variation of interaural time difference yielded symmetrical tuning curves in the midbrain pathway. By contrast, the typical forebrain-tuning curve was asymmetric with a steep slope crossing zero time difference and a less-steep slope toward larger contralateral time disparities. Low sound frequencies contributed sensitivity to contralateral leading sounds underlying these asymmetries, whereas high frequencies enhanced the steepness of slopes at small interaural time differences. Furthermore, the peaks of time-disparity tuning curves were wider in the forebrain than in the midbrain. The distribution of the steepest slopes of best interaural time differences in the auditory arcopallium, but not in the external nucleus of the inferior colliculus, was centered at zero time difference. The distribution observed in the auditory arocpallium is reminiscent of the situation observed in small mammals. We speculate that the forebrain representation may serve as a population code supporting fine discrimination of central interaural time differences and coarse indication of laterality of a stimulus for large interaural time differences.

scholarly journals Frequency-dependent variation in the two-dimensional beam pattern of an echolocating dolphin

2011 ◽  
Vol 7 (6) ◽  
pp. 836-839 ◽  
Author(s):  
Josefin Starkhammar ◽  
Patrick W. Moore ◽  
Lois Talmadge ◽  
Dorian S. Houser
Keyword(s):  
Sound Propagation ◽  
Sound Field ◽  
Spatial Separation ◽  
Acoustic Properties ◽  
Maximum Pressure ◽  
Frequency Bandwidth ◽  
Sound Sources ◽  
Pressure Peak ◽  
Prey Localization ◽  
Dominant Peak

Recent recordings of dolphin echolocation using a dense array of hydrophones suggest that the echolocation beam is dynamic and can at times consist of a single dominant peak, while at other times it consists of forward projected primary and secondary peaks with similar energy, partially overlapping in space and frequency bandwidth. The spatial separation of the peaks provides an area in front of the dolphin, where the spectral magnitude slopes drop off quickly for certain frequency bands. This region is potentially used to optimize prey localization by directing the maximum pressure slope of the echolocation beam at the target, rather than the maximum pressure peak. The dolphin was able to steer the beam horizontally to a greater extent than previously described. The complex and dynamic sound field generated by the echolocating dolphin may be due to the use of two sets of phonic lips as sound sources, or an unknown complexity in the sound propagation paths or acoustic properties of the forehead tissues of the dolphin.

INVESTIGATION OF THE CONTRIBUTIONS OF SOUND SOURCES TO EXTERNAL TRAIN NOISE

Akustika ◽  
2021 ◽  
pp. 250
Author(s):  
Denis Kuklin ◽  
Marina Butorina ◽  
Aleksandr Vasilyev
Keyword(s):  
High Speed ◽  
Experimental Studies ◽  
Sound Field ◽  
Sound Level ◽  
Railway Transport ◽  
Noise Sources ◽  
Sound Sources ◽  
High Speed Trains ◽  
Field Formation

The article discusses the method and results of in-situ investigations of the contributions of noise sources of railway transport to the external sound field. The main sources that form the external sound field are pantograph, inter-car coupler and wheel-rail interaction. Experimental studies were carried out for electric trains, passenger, high-speed and freight trains moving with different velocities. The tests have shown the wheel-rail pair makes the main contribution to the external field formation for all types of trains is made by. For high-speed trains and electric trains at speeds over 100 km/h, the noise of the pantograph begins to make a certain contribution. The sound level of electric and high-speed trains increases by 1.5 dBA and sound level of passenger and freight trains increases by 3-3.5 dBA with the increase of speed per each 10 km/h.

scholarly journals Microsecond Interaural Time Difference Discrimination Restored by Cochlear Implants After Neonatal Deafness

2018 ◽  
Author(s):  
Nicole Rosskothen-Kuhl ◽  
Alexa N Buck ◽  
Kongyan Li ◽  
Jan W H Schnupp
Keyword(s):  
Cochlear Implants ◽  
Critical Period ◽  
Interaural Time Difference ◽  
Spatial Hearing ◽  
Time Difference ◽  
Interaural Time Differences ◽  
Behavioral Thresholds ◽  
Essentially Normal ◽  
High Degree ◽  
Prelingually Deaf

AbstractCochlear implants (CIs) can restore a high degree of functional hearing in deaf patients however spatial hearing remains poor, with many early deaf CI users reported to have no measurable sensitivity to interaural time differences (ITDs) at all. Deprivation of binaural experience during an early critical period is often blamed for this shortcoming. However, we show that neonatally deafened rats provided with precisely synchronized CI stimulation in adulthood can be trained to localize ITDs with essentially normal behavioral thresholds near 50 μs. Furthermore, neonatally deaf rats show high physiological sensitivity to ITDs immediately after binaural implantation in adulthood. The fact that our neonatally deaf CI rats achieved very good behavioral ITD thresholds while prelingually deaf human CI patients usually fail to develop a useful sensitivity to ITD raises urgent questions about whether shortcomings in technology or treatment may be behind the usually poor binaural outcomes for current binaural CI patients.

Binaural Hearing of Speech for Aided and Unaided Conditions

1969 ◽  
Vol 12 (3) ◽  
pp. 650-664 ◽  
Author(s):  
Donald D. Dirks ◽  
Richard A. Wilson
Keyword(s):  
Hearing Loss ◽  
Sensorineural Hearing Loss ◽  
Speech Intelligibility ◽  
Sound Field ◽  
Binaural Hearing ◽  
Normal Hearing ◽  
Field Conditions ◽  
Interaural Time Differences ◽  
Binaural Listening ◽  
Signal Sources

Differences in speech intelligibility and identification between binaural, monaural near ear, and monaural far ear conditions were studied in sound field conditions. Scores from listeners with normal hearing and with sensorineural losses were evalated in sound field conditions (unaided) and under conditions of hearing aid amplification (aided). For both conditions listeners with sensorineural hearing loss obtained a binaural advantage similar to that found for normal listeners. The binaural advantage could be demonstrated only when the primary and/or competing signal sources were located at an azimuth which resulted in interaural time differences for at least one of the signals. When the signals arrived simultaneously at the ears from the same loudspeaker, no binaural advantage was obtained. Differences in intelligibility and identification scores between monaural near ear and far ear conditions (6.0 dB) were almost twice as large as those found between binaural listening and monaural near ear listening (3.3 dB).

Segregation of Multiple Talkers in the Vertical Plane: Implications for the Design of a Multiple Talker Display

2002 ◽  
Vol 46 (4) ◽  
pp. 588-591 ◽  
Author(s):  
Ken I. McAnally ◽  
Robert S. Bolia ◽  
Russell L Martin ◽  
Geoff Eberle ◽  
Douglas S. Brungart
Keyword(s):  
Speech Intelligibility ◽  
Vertical Plane ◽  
Spatial Separation ◽  
Median Plane ◽  
Spatial Audio ◽  
Interaural Time Differences ◽  
The Third ◽  
Release From Masking

Three experiments were conducted to evaluate the effect of spatial separation of multiple talkers in the vertical plane on speech intelligibility. The first experiment demonstrated a release from masking due to separation in the median plane, and that this release was not due to the presence of residual interaural time differences (ITDs). The second experiment showed that this release corresponded to an increase in signal level of 1.3 dB. The third experiment demonstrated that the increase in intelligibility due to separation in elevation and that due to separation in azimuth were not additive. Results are discussed in terms of their implications for the design of spatial audio displays.

scholarly journals Microsecond interaural time difference discrimination restored by cochlear implants after neonatal deafness

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Nicole Rosskothen-Kuhl ◽  
Alexa N Buck ◽  
Kongyan Li ◽  
Jan W H Schnupp
Keyword(s):  
Cochlear Implant ◽  
Cochlear Implants ◽  
Early Development ◽  
Critical Period ◽  
Interaural Time Difference ◽  
Spatial Hearing ◽  
Time Difference ◽  
Interaural Time Differences ◽  
Behavioral Thresholds ◽  
Essentially Normal

Spatial hearing in cochlear implant (CI) patients remains a major challenge with many early deaf users reported to have no measurable sensitivity to interaural time differences (ITDs). Deprivation of binaural experience during an early critical period is often hypothesized to be the cause of this shortcoming. However, we show that neonatally deafened (ND) rats provided with precisely synchronized CI stimulation in adulthood can be trained to lateralize ITDs with essentially normal behavioral thresholds near 50 μs. Furthermore, comparable ND rats show high physiological sensitivity to ITDs immediately after binaural implantation in adulthood. Our result that ND CI rats achieved very good behavioral ITD thresholds while prelingually deaf human CI patients often fail to develop a useful sensitivity to ITD raises urgent questions concerning the possibility that shortcomings in technology or treatment, rather than missing input during early development, may be behind the usually poor binaural outcomes for current CI patients.

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