A Study of Wideband Absorbers in a Non-Environment Control Room: Characterisation of the Sound Field by Means of p-p Probe Measurements

2011 ◽  
Vol 97 (1) ◽  
pp. 82-92 ◽  
Author(s):  
Soledad Torres-Guijarro ◽  
Antonio Pena ◽  
Alfonso Rodríguez-Molares ◽  
Norberto Degara-Quintela
Keyword(s):  
Sound Field ◽  
Control Room ◽  
Environment Control ◽  
Probe Measurements

A Study of Wideband Absorbers in a Non-Environment Control Room: Normal Absorption Coefficient Measurement and Analysis

2012 ◽  
Vol 98 (3) ◽  
pp. 411-417 ◽  
Author(s):  
Soledad Torres-Guijarro ◽  
Antonio Pena ◽  
David Pérez-Cabo ◽  
Norberto Degara-Quintela
Keyword(s):  
Absorption Coefficient ◽  
Acoustic Impedance ◽  
Low Frequency ◽  
Sound Field ◽  
Control Room ◽  
Rear Wall ◽  
Channel Opening ◽  
Measurement And Analysis ◽  
Environment Control ◽  
Coefficient Measurement

This contribution concludes the study initiated in [1] about the wideband absorbers of the rear wall in a nonenvironment control room at the “Universidade de Vigo”. The specific acoustic impedance will be calculated from microphone signals of a p-p intensity probe, and the H2 estimator will demonstrate that it provides the best estimate both at fixed measuring points and in scanning. The absorption coefficient calculated from the specific acoustic impedance is related to the sound field characterisation in the vicinity of the panels: in the very low frequency region it presents maxima and minima attributable to the behaviour of the channels between panels as open-closed tubes, and also shows the effect of the first transverse standing wave in fixed point measurements performed in the centre of the channel opening. This effect disappears in the scanning measurement providing an average absorption curve in a wide area in front of the absorbers. A simple model can be made from the results for the absorption of the wideband absorbers of the rear wall of the room.

scholarly journals 3D Acoustic Field Intensity Probe Design and Measurements

2016 ◽  
Vol 41 (4) ◽  
pp. 701-711 ◽  
Author(s):  
Józef Kotus ◽  
Andrzej Czyżewski ◽  
Bożena Kostek
Keyword(s):  
Acoustic Field ◽  
Field Intensity ◽  
Research Study ◽  
Sound Field ◽  
Sound Intensity ◽  
Calibration Procedure ◽  
Measurement Procedure ◽  
Probe Design ◽  
Intensity Measurements ◽  
Probe Measurements

Abstract The aim of this paper is two-fold. First, some basic notions on acoustic field intensity and its measurement are shortly recalled. Then, the equipment and the measurement procedure used in the sound intensity in the performed research study are described. The second goal is to present details of the design of the engineered 3D intensity probe, as well as the algorithms developed and applied for that purpose. Results of the intensity probe measurements along with the calibration procedure are then contained and discussed. Comparison between the engineered and the reference commercial probe confirms that the designed construction is applicable to the sound field intensity measurements with a sufficient effectiveness.

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.

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