Sound Absorption Measurement in a Circular Tube Using the Echo-Pulse Method

The authors have been published a series of papers on a measurement method for sound absorption characteristics of materials using ensemble averaging technique, i.e., EA method. The papers' results included measurement mechanisms, measurement uncertainty, and so on. Herein, to examine adaptability, especially in in-situ conditions, the EA method is applied to measure absorption characteristics of materials installed in two gymnasiums. A glass-wool panel with the dimension of 0.5 m by 0.5 m by 0.05 m and with the density of 32 kg m^-3 was brought around and measured to check the measurement consistency. Several measurements were conducted during badminton plays were undergoing. Measured sound absorption coefficients revealed that most results agree well with those measured in reverberation rooms. Certain improvement is necessary for the specimen brought to the in-situ measurement to keep the consistency. The inconsistency is considered to originate from unstable conditions between the specimen and floor.

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A Tone‐Burst Technique of Sound‐Absorption Measurement

The Journal of the Acoustical Society of America ◽

10.1121/1.1912276 ◽

1970 ◽

Vol 48 (6A) ◽

pp. 1299-1303 ◽

Cited By ~ 3

Author(s):

John G. Powell ◽

John J. Van Houten

Keyword(s):

Sound Absorption ◽

Tone Burst ◽

Absorption Measurement

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DESAIN OF ACOUSTIC SANDWICH COMPOSITE FROM FOAM CONCRETE AND PALM FIBER

Jurnal Natural ◽

10.24815/jn.v18i2.9706 ◽

2018 ◽

Vol 18 (2) ◽

pp. 72-76

Author(s):

Devya Kartika Devya ◽

Mursal Mursal ◽

Zulkarnain Djalil

Keyword(s):

White Noise ◽

Sound Absorption ◽

Bottom Layer ◽

Absorption Measurement ◽

Sample Thickness ◽

Sandwich Composite ◽

Foam Concrete ◽

Low Frequencies ◽

Palm Fiber ◽

Layer Composition

The purpose of this research were to investigate the influence of palm fiber composition and the number of hole cavities was varied with design Acoustic Sandwich Composite on sound absorption of acoustic panel. Acoustic panel were made of palm fiber as core and foam concreate as skin upper layer and bottom layer where there is a hole cavity on skin upper layer. Composition and the number of hole cavities was varied from 1 to 3 kg and the number of hole cavities from 25 to 81 hole. Sound absorption measurement was conducted by using reverberation room method based on ISO-354 (2003) with pink and white noise as sound source.The results showed that sample thickness affect acoustic absorption value effectively shifted at low frequencies, as in this research the best sound absorption occurs in panel with composition palm fiber most widely 3 kg, but coeffesient absorpsi value effective is in the range 250 Hz and use the number of hole cavities at skin upper layer of each sample effectively cause sound absorption coeffisient value increased, for both pink and white noise from sound source.Keyword : acoustic panel, foam concrete, palm fiber, sandwich composite, and absorption coefficient

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Signal analysis in the sound absorption measurement procedure: The importance of time subtraction and reference surface corrections

The Journal of the Acoustical Society of America ◽

10.1121/1.2933356 ◽

2008 ◽

Vol 123 (5) ◽

pp. 3200-3200 ◽

Cited By ~ 1

Author(s):

Paolo Guidorzi ◽

Massimo Garai

Keyword(s):

Signal Analysis ◽

Sound Absorption ◽

Measurement Procedure ◽

Absorption Measurement ◽

Reference Surface

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An improved double-beam pulse method for measurement of sound absorption for chemical relaxation studies

Ultrasonics ◽

10.1016/0041-624x(73)90210-2 ◽

1973 ◽

Vol 11 (4) ◽

pp. 191

Keyword(s):

Sound Absorption ◽

Pulse Method ◽

Double Beam ◽

Chemical Relaxation ◽

Relaxation Studies

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Analysis of the Influence of Static Flow Resistance on the Sound Absorption Properties of Aluminum Foam

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.535-537.1459 ◽

2012 ◽

Vol 535-537 ◽

pp. 1459-1462 ◽

Cited By ~ 1

Author(s):

Huai Qian Bao ◽

Ning Zhang ◽

Xue Gang Hou

Keyword(s):

Sound Absorption ◽

Flow Resistance ◽

Aluminum Foam ◽

Circular Tube ◽

Peak Frequency ◽

Absorption Properties ◽

Absorption Frequency ◽

Porous Aluminum ◽

Static Flow ◽

Resistance Value

For the complexity of the internal microstructure of porous aluminum foam, on the basis of Rayleigh-Kirchhoff circular tube model, taking viscosity loss and thermal transmission, the paper establishes a simplified theoretical model for sound absorption properties of aluminum foam. The paper also calculates and analyzes the influence of Static flow resistance on the sound absorption properties in the rigidity and cavity backing. The results show that the peak frequency moves to lower with the increasing of the thickness of the air layer. What’s more, there is a direct corresponding relation between flow resistance and the best sound absorption frequency range of aluminum foam. In a reasonable range of flow resistance value, the capability of sound absorption reach optimal, Aluminum Foam won’t have fine sound absorption capability if the value of flow resistance is too big or small.

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