scholarly journals Binaural Recordings in Natural Acoustic Environments: Estimates of Speech-Likeness and Interaural Parameters

2020 ◽  
Vol 24 ◽  
pp. 233121652097285
Author(s):  
S. Theo Goverts ◽  
H. Steven Colburn
Keyword(s):  
Speech Intelligibility ◽  
Transfer Functions ◽  
Interaural Time Difference ◽  
Interaural Level Difference ◽  
Clinical Test ◽  
Natural Environments ◽  
Impaired Hearing ◽  
Large Variability ◽  
Frequency Bands ◽  
Interaural Difference

Binaural acoustic recordings were made in multiple natural environments, which were chosen to be similar to those reported to be difficult for listeners with impaired hearing. These environments include natural conversations that take place in the presence of other sound sources as found in restaurants, walking or biking in the city, and so on. Sounds from these environments were recorded binaurally with in-the-ear microphones and were analyzed with respect to speech-likeness measures and interaural difference measures. The speech-likeness measures were based on amplitude–modulation patterns within frequency bands and were estimated for 1-s time-slices. The interaural difference measures included interaural coherence, interaural time difference, and interaural level difference, which were estimated for time-slices of 20-ms duration. These binaural measures were documented for one-fourth-octave frequency bands centered at 500 Hz and for the envelopes of one-fourth-octave bands centered at 2000 Hz. For comparison purposes, the same speech-likeness and interaural difference measures were computed for a set of virtual recordings that mimic typical clinical test configurations. These virtual recordings were created by filtering anechoic waveforms with available head-related transfer functions and combining them to create multiple source combinations. Overall, the speech-likeness results show large variability within and between environments, and they demonstrate the importance of having information from both ears available. Furthermore, the interaural parameter results show that the natural recordings contain a relatively small proportion of time-slices with high coherence compared with the virtual recordings; however, when present, binaural cues might be used for selecting intervals with good speech intelligibility for individual sources.

The Role of Binaural and Fundamental Frequency Difference cues in the Identification of Concurrently Presented Vowels

1994 ◽  
Vol 47 (3) ◽  
pp. 545-563 ◽  
Author(s):  
Trevor M. Shackleton ◽  
Ray Meddis ◽  
Michael J. Hewitt
Keyword(s):  
Signal To Noise Ratio ◽  
Interaural Time Difference ◽  
Interaural Level Difference ◽  
Relative Importance ◽  
Voice Pitch ◽  
Binaural Processing ◽  
Pitch Difference ◽  
Interaural Difference ◽  
Difference Effect

The relative importance of voice pitch and interaural difference cues in facilitating the recognition of both of two concurrently presented synthetic vowels was measured. The interaural difference cues used were an interaural time difference (400 μsec ITD), two magnitudes of interaural level difference (15 dB and infinite ILD), and a combination of ITD and ILD (400 μsec plus 15 dB). The results are analysed separately for those cases where both vowels are identical and those where they are different. When the two vowels are different, a voice pitch difference of one semitone is found to improve the percentage of correct reports of both vowels by 35.8% on average. However, the use of interaural difference cues results in an improvement of 11.5% on average when there is a voice pitch difference of one semitone, but only a non-significant 0.1% when there is no voice pitch difference. When the two vowels are identical, imposition of either a voice pitch difference or binaural difference reduces performance, in a subtractive manner. It is argued that the smaller size of the interaural difference effect is not due to a “ceiling effect” but is characteristic of the relative importance of the two kinds of cues in this type of experiment. The possibility that the improvement due to interaural difference cues may in fact be due to monaural processing is discussed. A control experiment is reported for the ITD condition, which suggests binaural processing does occur for this condition. However, it is not certain whether the improvement in the ILD condition is due to binaural processing or use of the improvement in signal-to-noise ratio for a single vowel at each ear.

The Effect of Nonlinear Amplitude Growth on the Speech Perception Benefits Provided by a Single-Sided Vocoder

2019 ◽  
Vol 62 (3) ◽  
pp. 745-757 ◽  
Author(s):  
Jessica M. Wess ◽  
Joshua G. W. Bernstein
Keyword(s):  
Transfer Functions ◽  
Spatial Configuration ◽  
Free Field ◽  
Spatial Separation ◽  
Compression And Expansion ◽  
Interaural Difference ◽  
Interaural Differences ◽  
Single Sided Deafness ◽  
Perceptual Separation ◽  
Loudness Growth

PurposeFor listeners with single-sided deafness, a cochlear implant (CI) can improve speech understanding by giving the listener access to the ear with the better target-to-masker ratio (TMR; head shadow) or by providing interaural difference cues to facilitate the perceptual separation of concurrent talkers (squelch). CI simulations presented to listeners with normal hearing examined how these benefits could be affected by interaural differences in loudness growth in a speech-on-speech masking task.MethodExperiment 1 examined a target–masker spatial configuration where the vocoded ear had a poorer TMR than the nonvocoded ear. Experiment 2 examined the reverse configuration. Generic head-related transfer functions simulated free-field listening. Compression or expansion was applied independently to each vocoder channel (power-law exponents: 0.25, 0.5, 1, 1.5, or 2).ResultsCompression reduced the benefit provided by the vocoder ear in both experiments. There was some evidence that expansion increased squelch in Experiment 1 but reduced the benefit in Experiment 2 where the vocoder ear provided a combination of head-shadow and squelch benefits.ConclusionsThe effects of compression and expansion are interpreted in terms of envelope distortion and changes in the vocoded-ear TMR (for head shadow) or changes in perceived target–masker spatial separation (for squelch). The compression parameter is a candidate for clinical optimization to improve single-sided deafness CI outcomes.

scholarly journals Design and Decomposition Analysis of Mixing Zone Structures on Flame Dynamics for a Swirl Burner

Energies ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 6744
Author(s):  
Yang Yang ◽  
Zhijian Yu
Keyword(s):  
Transfer Functions ◽  
Decomposition Analysis ◽  
Dynamic Mode Decomposition ◽  
Dynamic Mode ◽  
Streamwise Vortices ◽  
Frequency Bands ◽  
Time Dynamic ◽  
Burner Exit ◽  
Decomposition Procedure ◽  
Flame Structures

The recirculation zone and the swirl flame behavior can be influenced by the burner exit shape, and few studies have been made into this structure. Large eddy simulation was carried out on 16 cases to distinguish critical geometry factors. The time series of the heat release rate were decomposed using seasonal-trend decomposition procedure to exclude the effect of short physical time. Dynamic mode decomposition (DMD) was performed to separate flame structures. The frequency characteristics extracted from the DMD modes were compared with those from the flame transfer functions. Results show that the flame cases can be categorized into three types, all of which are controlled by a specific geometric parameter. Except one type of flame, they show nonstationary behavior by the Kwiatkowski–Phillips–Schmidt–Shin test. The frequency bands corresponding to the coherent structures are identified. The flame transfer function indicates that the flame can respond to external excitation in the frequency range 100–300 Hz. The DMD modes capture the detailed flame structures. The higher frequency bands can be interpolated as the streamwise vortices and shedding vortices. The DMD modes, which correspond to the bands of flame transfer functions, can be estimated as streamwise vortices at the edges.

scholarly journals Disparity in interaural time difference improves the accuracy of neural representations of individual concurrent narrowband sounds in rat inferior colliculus and auditory cortex

2020 ◽  
Vol 123 (2) ◽  
pp. 695-706
Author(s):  
Lu Luo ◽  
Na Xu ◽  
Qian Wang ◽  
Liang Li
Keyword(s):  
Auditory Cortex ◽  
Inferior Colliculus ◽  
Interaural Time Difference ◽  
Critical Role ◽  
Low Frequency ◽  
Time Difference ◽  
Neural Representation ◽  
Frequency Bands ◽  
Neural Segregation ◽  
Peripheral Auditory System

The central mechanisms underlying binaural unmasking for spectrally overlapping concurrent sounds, which are unresolved in the peripheral auditory system, remain largely unknown. In this study, frequency-following responses (FFRs) to two binaurally presented independent narrowband noises (NBNs) with overlapping spectra were recorded simultaneously in the inferior colliculus (IC) and auditory cortex (AC) in anesthetized rats. The results showed that for both IC FFRs and AC FFRs, introducing an interaural time difference (ITD) disparity between the two concurrent NBNs enhanced the representation fidelity, reflected by the increased coherence between the responses evoked by double-NBN stimulation and the responses evoked by single NBNs. The ITD disparity effect varied across frequency bands, being more marked for higher frequency bands in the IC and lower frequency bands in the AC. Moreover, the coherence between IC responses and AC responses was also enhanced by the ITD disparity, and the enhancement was most prominent for low-frequency bands and the IC and the AC on the same side. These results suggest a critical role of the ITD cue in the neural segregation of spectrotemporally overlapping sounds. NEW & NOTEWORTHY When two spectrally overlapped narrowband noises are presented at the same time with the same sound-pressure level, they mask each other. Introducing a disparity in interaural time difference between these two narrowband noises improves the accuracy of the neural representation of individual sounds in both the inferior colliculus and the auditory cortex. The lower frequency signal transformation from the inferior colliculus to the auditory cortex on the same side is also enhanced, showing the effect of binaural unmasking.

Adaptive plasticity of the auditory space map in the optic tectum of adult and baby barn owls in response to external ear modification

1994 ◽  
Vol 71 (1) ◽  
pp. 79-94 ◽  
Author(s):  
E. I. Knudsen ◽  
S. D. Esterly ◽  
J. F. Olsen
Keyword(s):  
Spatial Pattern ◽  
Optic Tectum ◽  
Interaural Time Difference ◽  
Rate Of Change ◽  
Adaptive Plasticity ◽  
Interaural Level Difference ◽  
External Ear ◽  
Site Location ◽  
Physiological Range ◽  
Barn Owls

1. This study demonstrates the influence of experience on the establishment and maintenance of the auditory map of space in the optic tectum of the barn owl. Auditory experience was altered either by preventing the structures of the external ears (the facial ruff and preaural flaps) from appearing in baby barn owls (baby ruff-cut owls) or by removing these structures in adults (adult ruff-cut owls). These structures shape the binaural cues used for localizing sounds in both the horizontal and vertical dimensions. 2. The acoustic effects of removing the external ear structures were measured using probe tube microphones placed in the ear canals. In both baby and adult ruff-cut owls, the spatial pattern of binaural localization cues was dramatically different from normal: interaural level difference (ILD) changed with azimuth instead of with elevation, the rate of change of ILD across space was decreased relative to normal, and the rate of change of interaural time difference (ITD) across frontal space was increased relative to normal. 3. The neurophysiological representations of ITD and ILD in the optic tectum were measured before and > or = 3 mo after ruff removal in adults and beginning at 4.5 months of age in baby ruff-cut owls. Multiunit tuning to ITD and to ILD was measured using dichotic stimulation in ketamine-anesthetized owls. The tectal maps of ITD and ILD were reconstructed using visual receptive field location as a marker for recording site location in the optic tectum. 4. Adjustment of the tectal map of ITD to the altered spatial pattern of acoustic ITD was essentially complete in adults as well as in baby ruff-cut owls. This adjustment changed the magnification of ITD across the tectum, with resultant changes in ITD tuning at individual tectal sites of up to approximately 25 microseconds (approximately 5% of the physiological range) relative to normal values. 5. Adaptation of the tectal ILD map to the ruff-cut spatial pattern of acoustic ILD was substantial but clearly incomplete in both adult and baby ruff-cut owls. Although changes of up to approximately 15 dB (approximately 47% of the physiological range) relative to normal tuning were observed at certain tectal sites, the topography of the ILD map was always intermediate between normal and that predicted by the ruff-cut spatial pattern of acoustic ILD.(ABSTRACT TRUNCATED AT 400 WORDS)

The Impact of Reduced Speech Intelligibility on Reaction Time in a Naval Combat Environment

2017 ◽  
Vol 61 (1) ◽  
pp. 1570-1574 ◽  
Author(s):  
Benjamin Sheffield ◽  
John Ziriax ◽  
M. David Keller ◽  
William Barns ◽  
Douglas Brungart
Keyword(s):  
Hearing Loss ◽  
Speech Intelligibility ◽  
Noise Exposure ◽  
Impaired Hearing ◽  
Perceived Workload ◽  
Series Of Experiments ◽  
And Performance ◽  
And Control ◽  
The Military ◽  
The Impact

Despite attempts to limit noise exposure, noise-induced hearing loss remains prevalent in the military. Both hearing loss and the noise itself can lead to communication issues which could negatively impact operational performance. This study builds upon a series of experiments examining the relationship between reduced speech intelligibility and performance in a naval command and control environment by equipping Navy watch standers with hearing loss simulators that control speech intelligibility in real time as they were engaged in a simulated operational scenario. This effort focused on the effects that a Sailor with impaired hearing might have on unimpaired shipmates and how the mission might specifically be impacted. Results showed that as speech intelligibility decreased for the impaired watch stander perceived workload increased in an unimpaired shipmate and the latency of the crew to respond to incoming missile threats and a direct order to kill an enemy ship increased significantly.

Peaks in the Frequency Response of Hearing Aids: Evaluation of the Effects on Speech Intelligibility and Sound Quality

1996 ◽  
Vol 39 (2) ◽  
pp. 239-250 ◽  
Author(s):  
Ronald A. van Buuren ◽  
Joost M. Festen ◽  
Tammo Houtgast
Keyword(s):  
Frequency Response ◽  
Hearing Aids ◽  
Speech Intelligibility ◽  
Rating Scale ◽  
Sound Quality ◽  
Normal Hearing ◽  
Reference Frequency ◽  
Impaired Hearing ◽  
Speech Spectrum ◽  
Series Of Experiments

In a series of experiments, we introduced peaks of 10, 20, and 30 dB, in various combinations, onto a smooth reference frequency response. For each of the conditions, we evaluated speech intelligibility in noise, using a test as developed by Plomp and Mimpen (1979), and sound quality (for both speech and music), using a rating-scale procedure. We performed the experiments with 26 listeners with sensorineurally impaired hearing and 10 listeners with normal hearing. Signal processing was accomplished digitally; for each listener, the stimuli were filtered and subsequently amplified so that the average speech spectrum was well above the threshold of hearing at all frequencies. The results show that, as a result of the introduction of peaks onto the frequency response, speech intelligibility is affected more for the listeners with impaired hearing than for those with normal hearing. Sound-quality judgments tend to be less different between the listener groups. Conditions with 30-dB peaks especially show serious effects on both speech intelligibility and sound quality.

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