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 The Role of Interaural Differences, Head Shadow, and Binaural Redundancy in Binaural Intelligibility Benefits Among School-Aged Children

2021 ◽  
Vol 25 ◽  
pp. 233121652110453
Author(s):  
Z. Ellen Peng ◽  
Ruth Y. Litovsky
Keyword(s):  
Speech Intelligibility ◽  
Spatial Separation ◽  
Spatial Cues ◽  
Auditory Cues ◽  
Auditory Space ◽  
Early Maturation ◽  
School Aged Children ◽  
Listening Environments ◽  
Interaural Difference ◽  
Interaural Differences

In complex listening environments, children can benefit from auditory spatial cues to understand speech in noise. When a spatial separation is introduced between the target and masker and/or listening with two ears versus one ear, children can gain intelligibility benefits with access to one or more auditory cues for unmasking: monaural head shadow, binaural redundancy, and interaural differences. This study systematically quantified the contribution of individual auditory cues in providing binaural speech intelligibility benefits for children with normal hearing between 6 and 15 years old. In virtual auditory space, target speech was presented from  + 90° azimuth (i.e., listener's right), and two-talker babble maskers were either co-located (+ 90° azimuth) or separated by 180° (–90° azimuth, listener's left). Testing was conducted over headphones in monaural (i.e., right ear) or binaural (i.e., both ears) conditions. Results showed continuous improvement of speech reception threshold (SRT) between 6 and 15 years old and immature performance at 15 years of age for both SRTs and intelligibility benefits from more than one auditory cue. With early maturation of head shadow, the prolonged maturation of unmasking was likely driven by children's poorer ability to gain full benefits from interaural difference cues. In addition, children demonstrated a trade-off between the benefits from head shadow versus interaural differences, suggesting an important aspect of individual differences in accessing auditory cues for binaural intelligibility benefits during development.

scholarly journals Seismic Analysis of the Transportation Portal by the Combined Asymptotic Method

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Alexander Tyapin
Keyword(s):  
Asymptotic Method ◽  
Stiffness Matrix ◽  
Transfer Functions ◽  
Seismic Analysis ◽  
Dynamic Stiffness ◽  
Free Field ◽  
Structural Dynamic ◽  
Dynamic Stiffness Matrix ◽  
Double Support ◽  
Soil Dynamic

The author extends the previously proposed combined asymptotic method (CAM) of seismic SSI analysis for the multi-support systems and applies it to the transportation portal as a double-support system (together with the reactor building). The key issue is the development of the structural dynamic stiffness matrix condensed to the supports by the modal approach. Then the condensed structural matrix is combined with the soil dynamic stiffness matrix also condensed to the rigid basements. As a result, a very simple linear system is solved in the frequency domain. This gives the transfer functions from the free-field motion to the motion of the basements. The only important limitations are the linearity of the soil’s and structure’s properties and the rigidity of the basements. The results for the sample system are checked against the full SASSI solution. The results can be used to justify the further simplification of the system.

Soil-structure interaction at CDMG and USGS accelerograph stations

1989 ◽  
Vol 79 (1) ◽  
pp. 1-14
Author(s):  
C. B. Crouse ◽  
Behnam Hushmand
Keyword(s):  
Soil Structure ◽  
Transfer Functions ◽  
Ground Motions ◽  
Free Field ◽  
Soil Structure Interaction ◽  
Imperial Valley ◽  
Structure Interaction ◽  
Fundamental Frequencies ◽  
Vibration Tests ◽  
40 Hz

Abstract Forced harmonic and impulse-response vibration tests were conducted at several California accelerograph stations operated by the California Division of Mines and Geology (CDMG) and U.S. Geological Survey (USGS) to determine the extent to which soil-structure interaction may be affecting the recorded ground motions. The results of the tests on the foundations comprising USGS Station 6 in the Imperial Valley and CDMG Cholame 1E and Fault Zone 3 stations in the Cholame Valley indicated the presence of highly damped fundamental frequencies between 20 and 40 Hz. However, at the much larger Differential Array station, a masonry-block structure approximately 6 km southwest of Station 6, a moderately damped fundamental frequency of 12 Hz was observed. Approximate transfer functions between earthquake motions recorded at the stations and the free-field motions were computed from the response data obtained from the forced harmonic vibration tests. For the three smaller stations, these functions showed peak amplification factors ranging from 1.25 to 1.4 at frequencies between 20 and 40 Hz. The amplification at smaller frequencies was insignificant. For the Differential Array station, the amplification factor was 1.5 at 12 Hz and was roughly 0.6 for frequencies between 14 and 25 Hz. These results suggest that soil-structure interaction will have little effect on ground motions recorded at the smaller stations provided that most of the energy in these motions is confined to frequencies less than approximately 20 Hz. However, at the Differential Array station, soil-structure interaction probably has had, and will continue to have, a significant influence on the motions recorded at this station.

Spatial Tuning to Virtual Sounds in the Inferior Colliculus of the Guinea Pig

2003 ◽  
Vol 90 (4) ◽  
pp. 2648-2659 ◽  
Author(s):  
Susanne J. Sterbing ◽  
Klaus Hartung ◽  
Klaus-Peter Hoffmann
Keyword(s):  
White Noise ◽  
Inferior Colliculus ◽  
Transfer Functions ◽  
Free Field ◽  
Receptive Fields ◽  
Sound Intensity ◽  
Spatial Location ◽  
Average Diameter ◽  
Maximal Response ◽  
Spatial Tuning

How do neurons in the inferior colliculus (IC) encode the spatial location of sound? We have addressed this question using a virtual auditory environment. For this purpose, the individual head-related transfer functions (HRTFs) of 18 guinea pigs were measured under free-field conditions for 122 locations covering the upper hemisphere. From 257 neurons, 94% responded to the short (50-ms) white noise stimulus at 70 dB sound pressure level (SPL). Out of these neurons, 80% were spatially tuned with a receptive field that is smaller than a hemifield (at 70 dB). The remainder responded omnidirectionally or showed fractured receptive fields. The majority of the neurons preferred directions in the contralateral hemisphere. However, preference for front or rear positions and high elevations occurred frequently. For stimulation at 70 dB SPL, the average diameter of the receptive fields, based on half-maximal response, was less than a quarter of the upper hemisphere. Neurons that preferred frontal directions responded weakly or showed no response to posterior directions and vice versa. Hence, front/back discrimination is present at the single-neuron level in the IC. When nonindividual HRTFs were used to create the stimuli, the spatial receptive fields of most neurons became larger, split into several parts, changed position, or the response became omnidirectional. Variation of absolute sound intensity had little effect on the preferred directions of the neurons over a range of 20 to 40 dB above threshold. With increasing intensity, most receptive fields remained constant or expanded. Furthermore, we tested the influence of binaural decorrelation and stimulus bandwidth on spatial tuning. The vast majority of neurons with a low characteristic frequency (<2.5 kHz) lost spatial tuning under stimulation with binaurally uncorrelated noise, whereas high-frequency units were mostly unaffected. Most neurons that showed spatial tuning under broadband stimulation (white noise and 1 octave wide noise) turned omnidirectional when stimulated with 1/3 octave wide noise.

GABAergic Disinhibition Affects Responses of Bat Inferior Collicular Neurons to Temporally Patterned Sound Pulses

1998 ◽  
Vol 79 (5) ◽  
pp. 2303-2315 ◽  
Author(s):  
Yong Lu ◽  
Philip H.-S. Jen ◽  
Min Wu
Keyword(s):  
Transfer Functions ◽  
Average Rate ◽  
Free Field ◽  
Response Repetition ◽  
Modulation Transfer ◽  
Modulation Transfer Functions ◽  
Low Pass ◽  
Band Pass ◽  
Inferior Collicular ◽  
Sound Pulses

Lu, Yong, Philip H.-S. Jen, and Min Wu. GABAergic disinhibition affects responses of bat inferior collicular neurons to temporally patterned sound pulses. J. Neurophysiol. 79: 2303–2315, 1998. Using the big brown bat, Eptesicus fuscus, as a model mammalian auditory system, we studied the effect of GABAergic disinhibition by bicuculline on the responses of inferior collicular (IC) neurons to temporally patterned trains of sound pulses delivered at different pulse repetition rates (PRRs) under free-field stimulation conditions. All 66 neurons isolated from eight bats either discharged one to two impulses (phasic on responders, n = 41, 62%), three to eight impulses (phasic bursters, n = 19, 29%), or many impulses throughout the entire duration of the stimulus (tonicresponders, n = 6, 9%). Whereas 50 neurons responded vigorously to frequency-modulated (FM) pulses, 16 responded poorly ornot at all to FM pulses. Bicuculline application increased the number of impulses of all 66 neurons in response to 4 ms pulses by 15–1,425%. The application also changed most phasic on responders into phasic bursters or tonic responders, resulting in 12 (18%) phasic on responders, 34 (52%) phasic bursters, and 20 (30%) tonic responders. Response latencies of these neurons were either shortened ( n = 25, 38%) by 0.5–6.0 ms, lengthened ( n = 9, 14%) by 0.5–2.5 ms or not changed ( n = 32, 48%) on bicuculline application. Each neuron had a highest response repetition rate beyond which the neuron failed to respond. Bicuculline application increased the highest response repetition rates of 62 (94%) neurons studied. The application also increased the highest 100% pulse-locking repetition rates of 21 (32%) neurons and facilitated 27 (41%) neurons in response to more pulses at the same PRR than predrug conditions. According to average rate-based modulation transfer functions (average rate MTFs), all 66 neurons had low-pass filtering characteristics both before and after bicuculline application. According to total discharge rate-based modulation transfer functions (total rate MTFs), filtering characteristics of these neurons can be described as band-pass ( n = 52, 79%), low-pass ( n = 12, 18%), or high-pass ( n = 2, 3%) before bicuculline application. Bicuculline application changed the filtering characteristics of 14 (21%) neurons. According to synchronization coefficient-based modulation transfer functions, filtering characteristics of these neurons can be described as low-pass ( n = 41, 62%), all-pass ( n = 11, 17%), band-suppression ( n = 7, 10.5%), and band-suppression–band-pass filters ( n = 7, 10.5%). Bicuculline application changed filtering characteristics of 19 (29%) neurons.

Multimodal Perceptual Training for Improving Spatial Auditory Performance in Blind and Sighted Listeners

2015 ◽  
Vol 40 (4) ◽  
pp. 491-502
Author(s):  
Oana Bălan ◽  
Alin Moldoveanu ◽  
Florica Moldoveanu
Keyword(s):  
Haptic Feedback ◽  
Transfer Functions ◽  
Free Field ◽  
Perceptual Training ◽  
Auditory Displays ◽  
Sound Localisation ◽  
Visually Impaired People ◽  
Alternative Approach ◽  
Before And After ◽  
Auditory Performance

Abstract The use of individualised Head Related Transfer Functions (HRTF) is a fundamental prerequisite for obtaining an accurate rendering of 3D spatialised sounds in virtual auditory environments. The HRTFs are transfer functions that define the acoustical basis of auditory perception of a sound source in space and are frequently used in virtual auditory displays to simulate free-field listening conditions. However, they depend on the anatomical characteristics of the human body and significantly vary among individuals, so that the use of the same dataset of HRTFs for all the users of a designed system will not offer the same level of auditory performance. This paper presents an alternative approach to the use on non-individualised HRTFs that is based on a procedural learning, training, and adaptation to altered auditory cues.We tested the sound localisation performance of nine sighted and visually impaired people, before and after a series of perceptual (auditory, visual, and haptic) feedback based training sessions. The results demonstrated that our subjects significantly improved their spatial hearing under altered listening conditions (such as the presentation of 3D binaural sounds synthesised from non-individualized HRTFs), the improvement being reflected into a higher localisation accuracy and a lower rate of front-back confusion errors.

scholarly journals On the Effect of Bimodal Rehabilitation in Asymmetric Hearing Loss

2021 ◽  
Vol 10 (17) ◽  
pp. 3927
Author(s):  
Simonetta Monini ◽  
Chiara Filippi ◽  
Alessandra De Luca ◽  
Gerardo Salerno ◽  
Maurizio Barbara
Keyword(s):  
Hearing Loss ◽  
Hearing Aid ◽  
Free Field ◽  
Hearing Threshold ◽  
Beneficial Effects ◽  
Auditory Performance ◽  
Contralateral Ear ◽  
Single Sided Deafness ◽  
Asymmetric Hearing Loss

Background: Bone conductive implants (BCI) have been reported to provide greater beneficial effects for the auditory and perceptual functions of the contralateral ear in patients presenting with asymmetric hearing loss (AHL) compared to those with single-sided deafness (SSD). The aim of the study was to assess the effects of wearing a conventional hearing aid in the contralateral ear on BCI in terms of an improved overall auditory performance. Methods: eleven AHL subjects wearing a BCI in their worse hearing ear underwent an auditory evaluation by pure tone and speech audiometry in free field. This study group was obtained by adding to the AHL patients those SSD subjects that, during the follow-up, showed deterioration of the hearing threshold of the contralateral ear, thus presenting with the features of AHL. Four different conditions were tested and compared: unaided, with BCI only, with contralateral hearing aid (CHA) only and with BCI combined with CHA. Results: all of the prosthetic conditions caused a significant improvement with respect to the unaided condition. When a CHA was adopted, its combination with the BCI showed significantly better auditory performances than those achieved with the BCI only. Conclusions: the present study suggests the beneficial role of a CHA in BCI-implanted AHL subjects in terms of overall auditory performance.

scholarly journals Speech intelligibility with various head-related transfer functions: A computational modeling approach

2020 ◽  
Author(s):  
Axel Ahrens ◽  
Maria Cuevas-Rodriguez ◽  
W. Owen Brimijoin
Keyword(s):  
Transfer Function ◽  
Computational Modeling ◽  
Speech Intelligibility ◽  
Transfer Functions ◽  
Spatial Separation ◽  
Spatial Position ◽  
Auditory Model ◽  
Modeling Approach ◽  
Head Related Transfer Function

AbstractSpeech intelligibility is known to be affected by the relative spatial position between target and interferers. The benefit of a spatial separation is, along with other factors, related to the head-related transfer function (HRTF). The HRTF is individually different and thus, the cues that improve speech intelligibility might also be different. In the current study an auditory model was employed to predict speech intelligibility with a variety of HRTFs. The predicted speech intelligibility was found to vary across HRTFs. Thus, individual listeners might have different access to cues that are important for speech intelligibility.

Sign in / Sign up

Export Citation Format

Share Document