COMPARISON OF EARPHONE AND SOUND FIELD METHODS FOR ESTIMATING NOISE ATTENUATION OF FOAM EARPLUGS

AIHAJ ◽  
1993 ◽  
Vol 54 (6) ◽  
pp. 307-312 ◽  
Author(s):  
N. L. Carter ◽  
G. Upfold
Keyword(s):  
Sound Field ◽  
Noise Attenuation ◽  
Field Methods

SOPRANOISE - update and analysis of noise barrier database including new current results

2021 ◽  
Vol 263 (3) ◽  
pp. 3073-3084
Author(s):  
Marco Conter ◽  
Andreas Fuchs ◽  
Paul Reiter
Keyword(s):  
Sound Field ◽  
Research Programme ◽  
Field Conditions ◽  
Background Information ◽  
Noise Barriers ◽  
Field Methods ◽  
Acoustic Performance ◽  
Measurement Results ◽  
Noise Barrier ◽  
Single Number

In the frame of the SOPRANOISE project (funded by CEDR in the Transnational Road Research Programme 2018) work package 2 focused first on providing theoretical and practical background information on measurement of the acoustic performance of noise barriers due to a state-of-the-art regarding correlations and possible trends between diffuse (EN 1793-1, EN 1793-2) and direct sound field methods (EN 1793-5, EN 1793-6). After that, the objective of this research was to extend and update the database of the European noise barrier market developed during the QUIESST project, including more detailed analyses on single-number ratings as well as third-octave band measurement results. The data collected and the analysis performed show relevant facts and figures about acoustic performances of noise barriers measured under diffuse and direct sound field conditions, together with a better understanding of the respective significance, similarities and differences of these standardized methods, improving data analysis and correlations between these methods. This paper gives a general overview of the data collected, summarising the main results of the statistical analyses performed. Overall results and comparisons between results of measurements performed under diffuse and under direct sound field conditions are shown. Finally, conclusions and possible outlook of the research are presented.

Near-field scanning optical microscopy

1986 ◽  
Vol 44 ◽  
pp. 642-643
Author(s):  
E. Betzig ◽  
A. Harootunian ◽  
M. Isaacson ◽  
A. Lewis
Keyword(s):  
Near Field ◽  
Optical Microscope ◽  
Visible Radiation ◽  
Field Methods ◽  
Optical Elements ◽  
Optical Region ◽  
Order Of Magnitude ◽  
Nondestructive Imaging ◽  
Scanning Optical Microscopy ◽  
Near Field Scanning

In general, conventional methods of optical imaging are limited in spatial resolution by either the wavelength of the radiation used or by the aberrations of the optical elements. This is true whether one uses a scanning probe or a fixed beam method. The reason for the wavelength limit of resolution is due to the far field methods of producing or detecting the radiation. If one resorts to restricting our probes to the near field optical region, then the possibility exists of obtaining spatial resolutions more than an order of magnitude smaller than the optical wavelength of the radiation used. In this paper, we will describe the principles underlying such "near field" imaging and present some preliminary results from a near field scanning optical microscope (NS0M) that uses visible radiation and is capable of resolutions comparable to an SEM. The advantage of such a technique is the possibility of completely nondestructive imaging in air at spatial resolutions of about 50nm.

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.

Sound Field Reproduction Using Ambisonics and Irregular Loudspeaker Arrays

2014 ◽  
Vol E97.A (9) ◽  
pp. 1832-1839 ◽  
Author(s):  
Jorge TREVINO ◽  
Takuma OKAMOTO ◽  
Yukio IWAYA ◽  
Yôiti SUZUKI
Keyword(s):  
Sound Field

In Memoriam. Elżbieta Maria Walerian, Ph.D., D.Sc.

2015 ◽  
Vol 39 (1) ◽  
pp. 153-154
Author(s):  
Mirosław Meissner
Keyword(s):  
Acoustic Waves ◽  
Sound Field ◽  
Physical Acoustics ◽  
Serious Illness ◽  
Technological Research ◽  
Master Of Science ◽  
Science Degree ◽  
Environmental Acoustics ◽  
In Memoriam ◽  
Academy Of Sciences

Abstract Elżbieta M. Walerian, Ph.D., D.Sc., a retired employee of the Institute of Fundamental Technological Research of the Polish Academy of Sciences (IPPT PAN), passed away after a serious illness, on the 26th December 2013. She was one of the scientific leaders in the Section of Environmental Acoustics of IPPT PAN and her career, educational and organizational activities were inseparably linked with the acoustics. Elżbieta Walerian was born on August 9th 1950 in Poznań. She graduated from the Faculty of Mathematics, Physics and Chemistry of the Adam Mickiewicz University in Poznań, receiving her Master of Science degree in the environmental acoustics in 1973. Five years later, under the supervision of Professor Ignacy Malecki, she obtained her PhD title, in the physical acoustics, in IPPT PAN in Warsaw. In 1979 she began working at the Section of Environmental Acoustics of IPPT PAN, where she dealt with the diffraction of acoustic waves and a description of the sound field produced by vehicles moving in an urban area.

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