Variability of the sound field in the presence of internal Kelvin waves in a stratified lake: The Sea of Galilee as a case study

2019 ◽  
Vol 145 (3) ◽  
pp. 1671-1671
Author(s):  
Ernest Uzhansky ◽  
Boris Katsnelson ◽  
Andrey Lunkov ◽  
Ilia Ostrovsky
Keyword(s):  
Sound Field ◽  
Kelvin Waves ◽  
Stratified Lake

Fluctuations of the sound field in the presence of internal Kelvin waves in a stratified lake

2013 ◽  
Vol 134 (5) ◽  
pp. 3989-3989
Author(s):  
Boris Katsnelson ◽  
Andrey Lunkov ◽  
Ilia Ostrovsky
Keyword(s):  
Sound Field ◽  
Kelvin Waves ◽  
Stratified Lake

Tropical Cyclogenesis Associated with Kelvin Waves and the Madden–Julian Oscillation

2011 ◽  
Vol 139 (9) ◽  
pp. 2723-2734 ◽  
Author(s):  
Carl J. Schreck ◽  
John Molinari
Keyword(s):  
Tropical Cyclone ◽  
Tropical Cyclones ◽  
North Pacific ◽  
Western North Pacific ◽  
Diabatic Heating ◽  
Kelvin Waves ◽  
Tropical Cyclogenesis ◽  
Madden Julian Oscillation ◽  
Convective Envelope

The Madden–Julian oscillation (MJO) influences tropical cyclone formation around the globe. Convectively coupled Kelvin waves are often embedded within the MJO, but their role in tropical cyclogenesis remains uncertain. This case study identifies the influences of the MJO and a series of Kelvin waves on the formation of two tropical cyclones. Typhoons Rammasun and Chataan developed in the western North Pacific on 28 June 2002. Two weeks earlier, conditions had been unfavorable for tropical cyclogenesis because of uniform trade easterlies and a lack of organized convection. The easterlies gave way to equatorial westerlies as the convective envelope of the Madden–Julian oscillation moved into the region. A series of three Kelvin waves modulated the development of the westerlies. Cyclonic potential vorticity (PV) developed in a strip between the growing equatorial westerlies and the persistent trade easterlies farther poleward. Rammasun and Chataan emerged from the apparent breakdown of this strip. The cyclonic PV developed in association with diabatic heating from both the MJO and the Kelvin waves. The tropical cyclones also developed during the largest superposition of equatorial westerlies from the MJO and the Kelvin waves. This chain of events suggests that the MJO and the Kelvin waves each played a role in the development of Rammasun and Chataan.

Acoustic comfort in a worship space made of cross-laminated timber

2019 ◽  
Vol 26 (2) ◽  
pp. 121-138 ◽  
Author(s):  
Giulia Fratoni ◽  
Dario D’Orazio ◽  
Luca Barbaresi
Keyword(s):  
Speech Intelligibility ◽  
Spatial Perception ◽  
Sound Field ◽  
Design Development ◽  
Good Opportunity ◽  
Cross Laminated Timber ◽  
Worship Space ◽  
Acoustic Comfort ◽  
Sustainable Materials

The construction of a new worship space in cross-laminated timber provides a good opportunity to include acoustic needs in the whole design development. The surface porosity and the lightweight of wooden elements may be carefully considered in order to improve the intelligibility of priests’ voice. In this work, a practical approach for obtaining a global acoustic comfort using sustainable materials is provided, using geometrical acoustic simulations. Material properties and architectural geometries were taken into account in order to evaluate subjective reverberation, speech intelligibility, and spatial perception over the whole audience. Results show how the sound energy distribution in the case study follows the sound field models proposed by scholars and how the ceiling shape—inspired by industrial sheds—contributes to the acoustic comfort of the faithfuls.

Ambisonic-centred location sound recording - reinvigorating the Observational Documentary genre?

2021 ◽  
Author(s):  
Steve Whitford
Keyword(s):  
Academic Research ◽  
Sound Field ◽  
Microphone Arrays ◽  
Single Camera ◽  
Sound Recording ◽  
Physical Event ◽  
Event Space ◽  
3D Sound ◽  
Critical Attention

The art of location-based Sound Recording specifically, has been a neglected area of academic research.  I seek to address this by drawing critical attention to the intricacies and skills involved in location Sound Recording within single-camera Observational Documentaries (ObsDocs). I show how this art continues to be central to the creative process of production, in driving the narrative and shaping the text’s influence, within the pro-filmic space.I go on to consider the future for location-based Sound Recording within ObsDocs and its place in a new multi-platform, multi-screen consumption space.  Examining a case study, I seek to develop and define a new working methodology and aesthetic for the craft and art, predicated on an anticipated resurgence of the ObsDoc genre, centred around opportunities afforded by the emerging technologies of immersive sound: ambisonic microphone arrays being a vital part of that development. Ambisonics is a method for capturing a full 3D sound field, and its genre-bridging adaptability means it can be converted to a dynamically steerable binaural format. I argue that deploying an ambisonic-centred location Sound Recording methodology, fused with the art of recording unscripted actuality Sound within the pro-filmic geographic event-space, will offer new creative opportunities impacts for ObsDoc makers and crucially, tomorrow’s Documentary audiences. Presenting audiences with an exciting new ability to experience the sense of geographical place and physical event that immersive audio delivers, bears the potential of re-invigorating a content driven ObsDoc market, which once again, will foreground the primacy of neglected storytelling capabilities, in a New consumption World.

Case study: Measurement and treatment of severe flutter echo caused by a barrel-vaulted sanctuary ceiling

2019 ◽  
Vol 67 (5) ◽  
pp. 380-393 ◽  
Author(s):  
Heather L. Lai ◽  
Anne C. Balant ◽  
David Foote
Keyword(s):  
Impulse Response ◽  
Sound Pressure ◽  
Sound Field ◽  
Pressure Level ◽  
Reverberation Time ◽  
Frequency Range ◽  
Recommended Treatment ◽  
Before And After

This case study centers on a recently constructed church with a barrel-vaulted sanctuary ceiling exhibiting excessive reverberation times and flutter echo. Reverberation times in excess of 5 s in the speech frequency range were observed at locations along the tiled center aisle, along with correspondingly elevated sound pressure levels and a highly non-diffuse sound field. Preliminary measurements, which included covering the reflective center aisle, substantiated the hypothesis that the acoustical behavior was caused by the interaction between the center aisle and the barrel-vaulted ceiling. The proposed recommendations for retrofitting the space to improve intelligibility along the aisle were modified with a view toward attaining an acceptable reduction in the reverberation times while retaining the spacious acoustical quality of the sanctuary. Additional acoustical measurements were performed prior to and following the completion of the recommended treatment. This case study describes the series of measurements and presents results of the treatment, in terms of reverberation time, impulse response decay curves, impulse response time waveforms and spectrograms, and sound pressure level measures. The unique characteristics of flutter echo due to the barrel-vaulted ceiling before and after the successful acoustical treatment are described.

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