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All-Weather Microphones - Calibration and Uncertainty Evaluation Methods

100%
Wszołek G.
Acta Physica Polonica A
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2011
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vol. 119
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issue 6A
1081-1085
EN
The paper presents the problems encountered during calibration of devices equipped with all-weather microphones, which results in frequent omissions in the periodic check-up of monitoring systems. Such a check-up should be regularly carried out, as it would result in broadening and unification of the knowledge concerning the measurements and the evaluation of their uncertainty in the environmental conditions.
2
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Theoretical and Experimental Determination of the Sound-Absorbing Property Class of Acoustic Barriers

63%
Turkiewicz J., Wszołek G.
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vol. 125
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issue 4A
A-127-A-130
EN
The currently applicable PN-EN 1793-1 standard concerning anti-noise devices on roads recommends for acoustic barriers built along traffic routes to have panels characterized by good sound-absorbing properties. The sound-absorbing properties of these panels (wall elements) are to be specified by giving the values of the single-number sound absorption evaluation index DL_α and the absorption property class determined in accordance with the PN-EN 1793-3:2001 standard. Continuous regular acoustic studies of new materials heretofore not used in anti-noise protections are conducted in the Department of Mechanics and Vibroacoustics at AGH. This paper presents the findings of research that started with different porous materials physical absorption coefficient tests. The purpose of these preliminary tests was to pick out materials with best sound-absorbing properties from the group of acoustically tested materials. The chosen materials could be used as a sound-absorbing lining on panels (wall elements) used in the design of acoustic barriers. On the basis of the obtained results, two materials with values of the average physical sound absorption coefficient higher than 0.5 (α_{favg}>0.5) were picked out for further acoustic tests. This paper presents results of studies that had the final effect consisting in determining the values of the single-number sound absorption evaluation index DL_α and the absorption property class for two prototype panels of an acoustic barrier the sound-absorbing lining of which was made up of materials chosen after preliminary acoustic studies. The determination of sound-absorbing property classes was carried out both theoretically and experimentally. In order to be possible to reduce the costs of acoustic tests in the future, particularly of new materials in regard to which there is a margin of uncertainty of whether their sound-absorbing properties meet expectations, the authors determined sound-absorbing property classes of acoustic barriers theoretically and then compared theoretical results with the results of experimental tests.
3
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Quietness in the Soundscape of the Białowieża National Park

39%
Wiciak J., Mleczko D., Ozga A., Wszołek G., Wierzbicki J., Piechowicz J., Małecki P.
Acta Physica Polonica A
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2015
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vol. 128
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issue 1A
A-79-A-84
EN
The quietness, defined as the near or complete absence of sound, in the context of the natural environment protection, may be considered a state in which no undesired of foreign sounds occur, and, by analogy to noise, analyzed in two aspects: that pertaining to measurements and the subjective one. The article discusses the lowest levels of sounds recorded at night in the soundscape of the Białowieża Forest. Due to low levels of the examined sounds and the technical problems that occurred while the sounds were being measured and registered, the acoustic examination of the measurement set-up in an anechoic chamber has also been presented. The research is aimed at defining precisely the concept of quietness prevailing in the nature in the subjective aspect by determining both the range of levels and the characteristics of preferred sounds.
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