Reducing the Uncertainty of Sound Absorption Measurements Using the Impedance Tube Method

2013 ◽  
Author(s):  
X. Hua ◽  
D. W. Herrin
Keyword(s):  
Sound Absorption ◽  
Impedance Tube ◽  
Impedance Tube Method ◽  
Absorption Measurements

scholarly journals Comparison of sound absorption characteristics measured by impedance tube method and ensemble averaging technique on porous clay bricks

2021 ◽  
Vol 42 (3) ◽  
pp. 154-157
Author(s):  
Siwat Lawanwadeekul ◽  
Reiji Tomiku ◽  
Noriko Okamoto ◽  
Toru Otsuru ◽  
Masahiro Masuda ◽  
...  
Keyword(s):  
Sound Absorption ◽  
Ensemble Averaging ◽  
Impedance Tube ◽  
Averaging Technique ◽  
Clay Bricks ◽  
Impedance Tube Method ◽  
Absorption Characteristics

scholarly journals Identification of uncertainty levels of acoustic properties of biocomposites under different mounting conditions in impedance tube tests

2021 ◽  
Vol 69 (5) ◽  
pp. 392-400
Author(s):  
Hasan Koruk ◽  
Yusuf Saygili ◽  
Garip Genc ◽  
Kenan Y. Sanliturk
Keyword(s):  
Sound Absorption ◽  
Transmission Loss ◽  
Acoustic Properties ◽  
Petroleum Jelly ◽  
Impedance Tube ◽  
Hard Materials ◽  
Inner Diameter ◽  
Acoustic Properties Of Materials ◽  
Impedance Tube Method ◽  
Textured Materials

Impedance tube method is widely used to measure acoustic properties of materials. Although this method yields reliable acoustic properties for soft textured materials, uncertainty levels of measured acoustic properties for hard materials, including biocomposites, can be quite large, mainly due to uncertain mounting conditions. Here, the effects of mounting conditions on the acoustic properties of biocomposites in an impedance tube are investigated. First, nominally identical biocomposite samples with a diameter equal to the inner diameter of impedance tube are manufactured and their acoustic properties are determined. As hard materials practically cause fitting problems in the impedance tube, the diameters of samples are reduced, as in practice, by small amounts and acoustic properties of modified samples are determined. Furthermore, in order to match the diameters of samples to the inner diameter of impedance tube, different materials such as tape, petroleum jelly and cotton are applied around samples to close the air gap between the samples and the tube's inner wall. All the results are compared, and the uncertainty levels caused by different mounting conditions on the acoustic properties of biocomposites are identified. The results show that the transmission loss (TL) measurements are dramatically affected by the mounting conditions while the sound absorption conditions are less sensitive to the mounting conditions. The deviations in the measured TL levels are highest for the samples with tape and wax (10–15 dB). On the other hand, the deviations in the measured sound absorption coefficients are highest for the samples with cotton and tape (1–2%).

Foliar Sound Absorption Capacities of Tree Leaves by Impedance Tube Method

2021 ◽  
pp. 1-7
Author(s):  
Payal Rane - Acharekar ◽  
Ambika Joshi ◽  
Nitesh Joshi
Keyword(s):  
Sound Absorption ◽  
Tree Leaves ◽  
Impedance Tube ◽  
Impedance Tube Method

Sound Absorption and Insulation Properties of a Polyurethane Foam Mixed with Electrospun Nylon-6 and Polyurethane Nanofibre Mats

2019 ◽  
Vol 19 (6) ◽  
pp. 3558-3563 ◽  
Author(s):  
Mira Park ◽  
Hyeon Ku Park ◽  
Hye Kyoung Shin ◽  
Dawon Kang ◽  
Bishweshwar Pant ◽  
...  
Keyword(s):  
Polyurethane Foam ◽  
Sound Absorption ◽  
Nylon 6 ◽  
Sound Insulation ◽  
Electrospinning Technique ◽  
Acoustic Characteristics ◽  
Impedance Tube ◽  
Textile Materials ◽  
Electrospun Nanofibres ◽  
Impedance Tube Method

In recent years, noise has become a serious hazard and can have permanent biological and psychological effects on humans and other organisms in nature. Textile materials are commonly used as absorbent acoustic materials for noise reduction. This work examines the use of electrospun nylon-6 and polyurethane nanofibres (PU NFs) to improve the sound absorption and sound insulation properties of polyurethane foam. In this work, nylon-6 and polyurethane nanofibres were prepared by an electrospinning technique and were glued to a polyurethane foam. The sound absorption coefficient of the materials was measured by the impedance tube method. An impedance tube was used to measure the sound absorption and airborne sound insulation. The results showed decreased sound absorption properties, whereas the sound insulation was highly enhanced when polyurethane/nanofibre hybrids were used, as compared to the pristine polyurethane foam. Furthermore, the sound insulation properties of polyurethane foam were highly enhanced when the foam was combined with nylon-6 NFs, compared with the polyurethane foam with PU NFs. Therefore, by investigating the acoustic characteristics of electrospun nylon-6 and PU nanofibres, we believe that this study can broaden the application of electrospun nanofibres for sound pollution control.

scholarly journals STUDY AND ANALYSIS ON SOUND ABSORBING AND NOISE REDUCING PERFORMANCE OF TIMBER CONSTRUCTION WALL BASED ON ACOUSTIC SPIRAL MATASURFACE

Wood Research ◽  
2021 ◽  
Vol 66 (3) ◽  
pp. 341-352
Author(s):  
Haiyan Fu ◽  
Xinyue Zhao ◽  
Patrick Adjei ◽  
Zheng Wang ◽  
Xiaoli Wu
Keyword(s):  
Absorption Coefficient ◽  
Sound Absorption ◽  
Low Frequency ◽  
Sound Absorption Coefficient ◽  
Impedance Tube ◽  
Frequency Sound ◽  
Timber Construction ◽  
Absorption Performance ◽  
Impedance Tube Method ◽  
Structural Layer

Based on acoustic spiral metasurface, a spiral structural layer was designed to apply to timber construction interior wall. The sound absorption coefficient was measured by impedance tube method and compared with Helmholtz resonance structural layer, solid structural layer and air layer in traditional wall. The results show that the combination of the spiral structural layer and the wall can optimize the sound absorption performance of the wall in the medium and low frequency. Without reducing the overall sound-absorbing performance of the wall, can achieve perfect sound absorption in some medium and low frequency sound bands.

Sound absorption measurements at 10–60 kHz in near‐freezing sea water

1975 ◽  
Vol 58 (3) ◽  
pp. 608-619 ◽  
Author(s):  
G. R. Garrison ◽  
R. E. Francois ◽  
E. A. Pence
Keyword(s):  
Sound Absorption ◽  
Sea Water ◽  
Absorption Measurements

ABSORPTION MEASUREMENTS OF SOUND IN SEA WATER

1948 ◽  
Vol 26a (5) ◽  
pp. 306-312 ◽  
Author(s):  
G. J. Thiessen ◽  
F. W. Simpson ◽  
J. R. Leslie
Keyword(s):  
Fresh Water ◽  
Sound Absorption ◽  
Sea Water ◽  
Absorption Measurements

Sound absorption measurements, made with a diverging beam in sea water, are given. They cover frequencies from 0.35 to 2.3 Mc. per second and are somewhat lower than those given by Richardson for fresh water. Conclusive comparison between these results and fresh water results cannot be made. Advantages of using long distances are discussed.

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