Inter-ping sound field from a simulated mid-frequency active sonar, and its implication to marine mammal tonal masking

2016 ◽  
Author(s):  
Shane Guan ◽  
Brandon L. Southall ◽  
Jay Barlow ◽  
Joseph F. Vignola ◽  
John A. Judge ◽  
...  
Keyword(s):  
Marine Mammal ◽  
Sound Field ◽  
Active Sonar

Marine Mammal Active Sonar Test 2004 (MAST 2004)

2004 ◽  
Vol 115 (5) ◽  
pp. 2559-2559
Author(s):  
Peter J. Stein ◽  
Amy Vandiver ◽  
Geoffrey S. Edelson ◽  
Adam S. Frankel ◽  
Christopher W. Clark
Keyword(s):  
Marine Mammal ◽  
Active Sonar

Monitoring of marine mammal occurrence and acoustic behaviors in relation to mid-frequency active sonar using autonomous recorders deployed off the undersea warfare training range, Florida

2013 ◽  
Vol 134 (5) ◽  
pp. 4045-4045
Author(s):  
Thomas F. Norris ◽  
Julie Oswald ◽  
Tina M. Yack ◽  
Elizabeth Ferguson ◽  
Anurag Kumar ◽  
...  
Keyword(s):  
Marine Mammal ◽  
Active Sonar

scholarly journals Potential Audibility of Three Acoustic Harassment Devices (AHDs) to Marine Mammals in Scotland, UK

2019 ◽  
Vol 24 (4) ◽  
pp. 792-800
Author(s):  
Victoria L.G. Todd ◽  
Jian Jiang ◽  
Maximilian Ruffert
Keyword(s):  
Water Column ◽  
Marine Mammal ◽  
Marine Mammals ◽  
Transmission Loss ◽  
Sound Field ◽  
Depth Range ◽  
Fish Farms ◽  
Mammal Species ◽  
Industrial Operations ◽  
Aquaculture Facilities

The modelled acoustic characteristics of three Acoustic Harassment Devices (AHDs) deployed from a fully operational salmonid fish farm, located in the Sound of Mull, Scotland (UK) are presented, using empirical seabed and water column measurements at the same location. In the Beaufort Sea state 0, the depth range of 10--50 m is the maximum range at which AHDs are potentially audible to five marine mammal species. The species present within this survey region are: the harbour porpoise, Phocoena phocoena (99.1 km), the killer whale, Orcinus orca (110 km), the bottlenose dolphin, Tursiops truncatus (89.6 km), the common seal, Phoca vitulina (88 km), and the grey seal, Halichoerus grypus (69 km). Consequently, within the Sound of Mull, all three AHDs could be heard throughout the water column by all species. For two models of AHDs, a behavioural disturbance level of between 140 dB-180 dB is observed at 1.3 km. Habitat displacement is a cause for concern, particularly if several fish farms within a small area all deploy AHDs simultaneously. This can create a confusing sound field of varying intensity, which has potential to deter harbour porpoises from sections of their habitat. If positioned effectively, AHDs have the potential to deter all five marine mammal species from industrial operations such as aquaculture facilities. Source levels, propagation and transmission loss measurements were highly variable and should be considered as site specific, meaning new estimates should be made for each situation.

Decay of Temporary Threshold Shift in Noise

1973 ◽  
Vol 16 (2) ◽  
pp. 267-270 ◽  
Author(s):  
John H. Mills ◽  
Seija A. Talo ◽  
Gloria S. Gordon
Keyword(s):  
Sound Field ◽  
Threshold Shift ◽  
Temporary Threshold Shift ◽  
Octave Band ◽  
Band Noise ◽  
Lower Asymptote

Groups of monaural chinchillas trained in behavioral audiometry were exposed in a diffuse sound field to an octave-band noise centered at 4.0 k Hz. The growth of temporary threshold shift (TTS) at 5.7 k Hz from zero to an asymptote (TTS ∞ ) required about 24 hours, and the growth of TTS at 5.7 k Hz from an asymptote to a higher asymptote, about 12–24 hours. TTS ∞ can be described by the equation TTS ∞ = 1.6(SPL-A) where A = 47. These results are consistent with those previously reported in this journal by Carder and Miller and Mills and Talo. Whereas the decay of TTS ∞ to zero required about three days, the decay of TTS ∞ to a lower TTS ∞ required about three to seven days. The decay of TTS ∞ in noise, therefore, appears to require slightly more time than the decay of TTS ∞ in the quiet. However, for a given level of noise, the magnitude of TTS ∞ is the same regardless of whether the TTS asymptote is approached from zero, from a lower asymptote, or from a higher asymptote.

Modified Earpieces and CROS for High Frequency Hearing Losses

1968 ◽  
Vol 11 (1) ◽  
pp. 204-218 ◽  
Author(s):  
Elizabeth Dodds ◽  
Earl Harford
Keyword(s):  
Hearing Loss ◽  
Hearing Aids ◽  
High Frequency ◽  
Hearing Aid ◽  
Sound Field ◽  
Intensity Level ◽  
Test Results ◽  
High Frequency Hearing Loss ◽  
Increased Sensitivity ◽  
Difficult Cases

Persons with a high frequency hearing loss are difficult cases for whom to find suitable amplification. We have experienced some success with this problem in our Hearing Clinics using a specially designed earmold with a hearing aid. Thirty-five cases with high frequency hearing losses were selected from our clinical files for analysis of test results using standard, vented, and open earpieces. A statistical analysis of test results revealed that PB scores in sound field, using an average conversational intensity level (70 dB SPL), were enhanced when utilizing any one of the three earmolds. This result was due undoubtedly to increased sensitivity provided by the hearing aid. Only the open earmold used with a CROS hearing aid resulted in a significant improvement in discrimination when compared with the group’s unaided PB score under earphones or when comparing inter-earmold scores. These findings suggest that the inclusion of the open earmold with a CROS aid in the audiologist’s armamentarium should increase his flexibility in selecting hearing aids for persons with a high frequency hearing loss.

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