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Δευτέρα 1 Αυγούστου 2016
Shifts in frequency-modulated pulses recorded during an encounter with Blainville's beaked whales (Mesoplodon densirostris)
Echolocation signals produced by beaked whales (family: Ziphiidae) include frequency-modulated (FM) pulses that appear to have species-specific characteristics. To date there has been no established evidence that a single species of beaked whale might produce more than one type of FM pulse. In 2014 a group of Blainville's beaked whales (Mesoplodon densirostris) were sighted off of Southern California; recordings included FM pulses with significant increases in peak frequency, center frequency, and −10 dB bandwidth relative to FM pulses previously attributed to this species. This research suggests there may be greater variation in received beaked whale FM pulses than previously understood.
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A parametric vocal fold model based on magnetic resonance imaging
This paper introduces a parametric three-dimensional body-cover vocal fold model based on magnetic resonance imaging (MRI) of the human larynx. Major geometric features that are observed in the MRI images but missing in current vocal fold models are discussed, and their influence on vocal fold vibration is evaluated using eigenmode analysis. Proper boundary conditions for the model are also discussed. Based on control parameters corresponding to anatomic landmarks that can be easily measured, this model can be adapted toward a subject-specific vocal fold model for voice production research and clinical applications.
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Seafloor sound-speed profile characterization with non-parallel layering by the image source method: Application to CLUTTER'09 campaign data
The image source method was originally developed to estimate sediment sound speed as a function of depth assuming plane-layered sediments. Recently, the technique was extended to treat dipping, i.e., non-parallel layers and was tested using synthetic data. Here, the technique is applied to measured reflection data with dipping layers and mud volcanoes. The data were collected with an autonomous underwater vehicle towing a source (1600–3500 Hz) and a horizontal array of hydrophones. Data were collected every 3 m criss-crossing an area about 1 km2. The results provide a combination of two-dimensional sections of the sediment sound-speeds plotted in a three-dimensional picture.
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On the completeness and the linear dependence of the Cartesian multipole series in representing the solution to the Helmholtz equation
The (Cartesian) multipole series, i.e., the series comprising monopole, dipoles, quadrupoles, etc., can be used, as an alternative to the spherical or cylindrical wave series, in representing sound fields in a wide range of problems, such as source radiation, sound scattering, etc. The proofs of the completeness of the spherical and cylindrical wave series in these problems are classical results, and it is also generally agreed that the Cartesian multipole series spans the same space as the spherical waves: a rigorous mathematical proof of that statement has, however, not been presented. In the present work, such a proof of the completeness of the Cartesian multipole series, both in two and three dimensions, is given, and the linear dependence relations among different orders of multipoles are discussed, which then allows one to easily extract a basis from the multipole series. In particular, it is concluded that the multipoles comprising the two highest orders in the series form a basis of the whole series, since the multipoles of all the lower source orders can be expressed as a linear combination of that basis.
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Robustness against distortion of fundamental frequency cues in simulated electro-acoustic hearing.
Robustness against distortion of fundamental frequency cues in simulated electro-acoustic hearing.
J Acoust Soc Am. 2016 Jul;140(1):229
Authors: Vermeulen A, Verschuur C
Abstract
Speech recognition by cochlear implant users can be improved by adding an audible low frequency acoustic signal to electrical hearing; the resulting improvement is deemed "electro-acoustic stimulation (EAS) benefit." However, a crucial low frequency cue, fundamental frequency (F0), can be distorted via the impaired auditory system. In order to understand how F0 distortions may affect EAS benefit, normal-hearing listeners were presented monaurally with vocoded speech (frequencies >250 Hz) and an acoustical signal (frequencies <250 Hz) with differing manipulations of the F0 signal, specifically: a pure tone with the correct mean F0 but with smaller variations around this mean, or a narrowband of white noise centered around F0, at varying bandwidths; a pure tone down-shifted in frequency by 50 Hz but keeping overall frequency modulations. Speech-recognition thresholds improved when tones with reduced frequency modulation were presented, and improved significantly for noise bands maintaining F0 information. A down-shifted tone, or only a tone to indicate voicing, showed no EAS benefit. These results confirm that the presence of the target's F0 is beneficial for EAS hearing in a noisy environment, and they indicate that the benefit is robust to F0 distortion, as long as the mean F0 and frequency modulations of F0 are preserved.
PMID: 27475149 [PubMed - as supplied by publisher]
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Robustness against distortion of fundamental frequency cues in simulated electro-acoustic hearing.
Robustness against distortion of fundamental frequency cues in simulated electro-acoustic hearing.
J Acoust Soc Am. 2016 Jul;140(1):229
Authors: Vermeulen A, Verschuur C
Abstract
Speech recognition by cochlear implant users can be improved by adding an audible low frequency acoustic signal to electrical hearing; the resulting improvement is deemed "electro-acoustic stimulation (EAS) benefit." However, a crucial low frequency cue, fundamental frequency (F0), can be distorted via the impaired auditory system. In order to understand how F0 distortions may affect EAS benefit, normal-hearing listeners were presented monaurally with vocoded speech (frequencies >250 Hz) and an acoustical signal (frequencies <250 Hz) with differing manipulations of the F0 signal, specifically: a pure tone with the correct mean F0 but with smaller variations around this mean, or a narrowband of white noise centered around F0, at varying bandwidths; a pure tone down-shifted in frequency by 50 Hz but keeping overall frequency modulations. Speech-recognition thresholds improved when tones with reduced frequency modulation were presented, and improved significantly for noise bands maintaining F0 information. A down-shifted tone, or only a tone to indicate voicing, showed no EAS benefit. These results confirm that the presence of the target's F0 is beneficial for EAS hearing in a noisy environment, and they indicate that the benefit is robust to F0 distortion, as long as the mean F0 and frequency modulations of F0 are preserved.
PMID: 27475149 [PubMed - as supplied by publisher]
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Overcoming Barriers to Hearing Aid Adoption and In-Clinic Success with Flex:trial and Flex:upgrade
Low hearing aid penetration in the consumer marketplace remains a hot topic, and a great deal of energy is expended via surveys, think tanks and industry associations in search of a silver bullet solution. The general consensus is that the industry should focus on two areas to boost satisfaction levels and market penetration: Increase awareness of the issues created by untreated hearing loss and improve the quality of the amplified listening experience. Yet, despite increasingly advanced and attractive hearing devices, sophisticated online marketing strategies and industry awareness efforts, the average age of a first-time wearer remains where it has always been: in the late 60s to early 70s. 
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from #Audiology via ola Kala on Inoreader http://ift.tt/2anQ6rn
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Overcoming Barriers to Hearing Aid Adoption and In-Clinic Success with Flex:trial and Flex:upgrade
Low hearing aid penetration in the consumer marketplace remains a hot topic, and a great deal of energy is expended via surveys, think tanks and industry associations in search of a silver bullet solution. The general consensus is that the industry should focus on two areas to boost satisfaction levels and market penetration: Increase awareness of the issues created by untreated hearing loss and improve the quality of the amplified listening experience. Yet, despite increasingly advanced and attractive hearing devices, sophisticated online marketing strategies and industry awareness efforts, the average age of a first-time wearer remains where it has always been: in the late 60s to early 70s.
from #Audiology via ola Kala on Inoreader http://ift.tt/2anQ6rn
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from #Audiology via ola Kala on Inoreader http://ift.tt/2anQ6rn
via IFTTT
Overcoming Barriers to Hearing Aid Adoption and In-Clinic Success with Flex:trial and Flex:upgrade
Low hearing aid penetration in the consumer marketplace remains a hot topic, and a great deal of energy is expended via surveys, think tanks and industry associations in search of a silver bullet solution. The general consensus is that the industry should focus on two areas to boost satisfaction levels and market penetration: Increase awareness of the issues created by untreated hearing loss and improve the quality of the amplified listening experience. Yet, despite increasingly advanced and attractive hearing devices, sophisticated online marketing strategies and industry awareness efforts, the average age of a first-time wearer remains where it has always been: in the late 60s to early 70s.
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