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w słowach kluczowych: izolacyjność akustyczna od dźwięków powietrznych

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Using MLS methods in laboratory measurement of airborne sound insulation

Mleczko Dominik

Vibrations in Physical Systems

2021

Vol. 32, nr 2

art. no. 2021205

Following the requirements of ISO 10140, to determine the acoustic insulation, measurements of the sound pressure levels in the source (L1) and receiving (L2) rooms and the reverberation time measurements in the receiving room (T) should be performed. However, the standard does not indicate the measuring signal to be used for the measurements. Various measurement methods can be used, including the use of the broadband noise or MLS method. The article examines the influence of the applied measurement methodology on the determined spectra of acoustic insulation and the weighted sound reduction index Rw. The total uncertainty of determining the acoustic insulation properties and partial uncertainties in determining L1, L2 and T were also calculated. The analysis of the obtained results allows concluding that the applied measurement method has no significant impact on the obtained acoustic insulation values, and the obtained measurement differences may rather be the result of an insufficient sample size.

Experimental tests of the acoustic properties of sound-absorbing linings and cores of layered baffles

Kosała Krzysztof

Vibrations in Physical Systems

2021

Vol. 32, nr 1

art. no. 2021107

The article presents the results of research on the acoustic properties of materials used as sound-absorbing linings and cores in baffles of anti-noise protection. Using an impedance tube the spectral characteristics of the normal incidence sound absorption and sound transmission loss indices of 12 specimens of mineral wool with different density and thickness were determined. From these characteristics, the single-number weighted sound absorption coefficient αw and the sound reduction index Rw were calculated. To calculate the value of the Rw index on the basis of surface mass of the mineral wool specimen, a new formula was proposed. The insertion loss of an acoustic enclosure with one, two and three-layer walls with dimensions of 0.7×0.7 m, containing mineral wool, was determined. The best efficiency was achieved for the enclosure made of walls of layers: mineral wool, placed on the sound source side, steel plate and aluminium plate.

Badania możliwości poprawy izolacyjności akustycznej ściany drewnianej

Dulak L., Żuchowski R.

Fizyka Budowli w Teorii i Praktyce

2007

T. 2

25-28

Wyniki badaiń terenowych izolacyjności akustycznej ścian w budynku drewnianym, przeprowadzonych w ramach działalności naukowej Katedry Procesów Budowlanych [1], skłoniły autorów artykułu do kontynuacji tematu i poszerzenia wiedzy z tego zakresu o badania laboratoryjne wariantowych rozwiązań ścian drewnianych. Przedstawione wyniki badań próbują odpowiedzieć na pytanie jak przeprowadzone adaptacje ściany szkieletowej drewnianej wpływają na zmianę jej parametrów akustycznych.

Results of field measurement of sound insulation described in article [1 ], encourage to continuation of the work. Authors executed laboratory measurement of sound insulation of engineered wood wall framing. This paper presents results for elementary exterior wall, wall with additional thermal insulation and 3 walls with acoustics adaptations. After made adaptations, weighted apparent sound reduction index Rw increase from 35 dB to 56+59 dB. The results prove how strongly index value is depend on range frequencies. Evidently range 50+5000 Hz is proper for definition exterior wall acoustics parameters.