ASTM E2611-09

Standard Test Method for Measurement of Normal Incidence Sound Transmission of Acoustical Materials Based on the Transfer Matrix Method

SIGNIFICANCE AND USE
There are several purposes of this test:
For transmission loss: (a) to characterize the sound insulation characteristics of materials in a less expensive and less time consuming approach than Test Method E 90 and ISO 140-3 (“reverberant room methods”), (b) to allow small samples tested when larger samples are impossible to construct or to transport, (c) to allow a rapid technique that does not require an experienced professional to run.
For transfer matrix: (a) to determine additional acoustic properties of the material; (b) to allow calculation of acoustic properties of built-up or composite materials by the combination of their individual transfer matrices.
There are significant differences between this method and that of the more traditional reverberant room method. Specifically, in this approach the sound impinges on the specimen in a perpendicular direction (“normal incidence”) only, compared to the random incidence of traditional methods. Additionally, revereration room methods specify certain minimum sizes for test specimens which may not be practical for all materials. At present the correlation, if any, between the two methods is not known. Even though this method may not replicate the reverberant room methods for measuring the transmission loss of materials, it can provide comparison data for small specimens, something that cannot be done in the reverberant room method. Normal incidence transmission loss may also be useful in certain situations where the material is placed within a small acoustical cavity close to a sound source, for example, a closely-fitted machine enclosure or portable electronic device.
Transmission loss is not only a property of a material, but is also strongly dependent on boundary conditions inherent in the method and details of the way the material is mounted. This must be considered in the interpretation of the results obtained by this test method.
The quantities are measured as a function of frequency with a resolution ...
SCOPE
1.1 This test method covers the use of a tube, four microphones, and a digital frequency analysis system for the measurement of normal incident transmission loss and other important acoustic properties of materials by determination of the acoustic transfer matrix.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 28-Feb-2009
• ICS: 17.140.01 - Acoustic measurements and noise abatement in general
• Technical Committee: E33 - Building and Environmental Acoustics
• Drafting Committee: E33.01 - Sound Absorption

Relations

• Replaced By: ASTM E2611-17 - Standard Test Method for Normal Incidence Determination of Porous Material Acoustical Properties Based on the Transfer Matrix Method
• Effective Date: 01-Apr-2017
• Referred By: ASTM C634-22 - Standard Terminology Relating to Building and Environmental Acoustics
• Effective Date: 01-Mar-2009

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: E2611 − 09
Standard Test Method for
Measurement of Normal Incidence Sound Transmission of
1
Acoustical Materials Based on the Transfer Matrix Method
This standard is issued under the fixed designation E2611; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3. Terminology
1.1 This test method covers the use of a tube, four 3.1 Definitions—Theacousticalterminologyusedinthistest
microphones, and a digital frequency analysis system for the method is intended to be consistent with the definitions in
measurement of normal incident transmission loss and other Terminology C634.
important acoustic properties of materials by determination of
3.1.1 reference plane—an arbitrary section, perpendicular to
the acoustic transfer matrix.
the longitudinal axis of the tube that is used for the origin of
lineardimensions.Oftenitistheupstream(closesttothesound
1.2 The values stated in SI units are to be regarded as
source) face of the specimen but, when specimen surfaces are
standard. No other units of measurement are included in this
irregular, it may be any convenient plane near the specimen.
standard.
3.1.2 sound transmission coeffıcient, τ—(dimensionless) of
1.3 This standard does not purport to address all of the
a material in a specified frequency band, the fraction of
safety concerns, if any, associated with its use. It is the
airborne sound power incident on a material that is transmitted
responsibility of the user of this standard to establish appro-
by the material and radiated on the other side.
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
W
t
τ 5
W
i
2. Referenced Documents
where:
2
2.1 ASTM Standards:
W and W = the transmitted and incident sound power.
t i
C634 Terminology Relating to Building and Environmental
3.1.3 sound transmission loss, TL—of a material in a speci-
Acoustics
fied frequency band, ten times the common logarithm of the
E90 Test Method for Laboratory Measurement of Airborne
reciprocal of the sound transmission coefficient. The quantity
Sound Transmission Loss of Building Partitions and
so obtained is expressed in decibels.
Elements
E1050 Test Method for Impedance and Absorption of
W 1
i
TL 5 10 log 5 10 log
S D S D
Acoustical Materials Using aTube,Two Microphones and 10 10
W τ
t
a Digital Frequency Analysis System
3.1.3.1 Discussion—In this standard the symbol TL will be
n
2.2 ISO Standards: applied to sound which impinges at an angle normal to the test
ISO 140-3 Acoustics—Measurement of Sound Insulation in specimen, as opposed to an arbitrary or random angle of
Buildings and of Building Elements—Part 3: Laboratory incidence.
Measurement of Airborne Sound Insulation of Building
3.2 Symbols:
3
Elements
c = speed of sound, m/s.
3
ρ = density of air, kg/m .
f = frequency, hertz, (Hz).
1
ThistestmethodisunderthejurisdictionofASTMCommitteeE33onBuilding
G , G , etc. = auto power spectra (autospectrum) of the
and Environmental Acoustics and is the direct responsibility of Subcommittee 11 22
E33.01 on Sound Absorption. acoustic pressure signal at microphone locations 1, 2, and so
Current edition approved March 1, 2009. Published March 2009. DOI: 10.1520/
on.
E2611-09.
2 G , G , etc. = cross power spectrum (cross spectrum) of
For referenced ASTM standards, visit the ASTM website, www.astm.org, or 21 32
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM the acoustic pressure signals at location 2 relative to location 1,
Standards volume information, refer to the standard’s Document Summary page on
3 relative to 1, and so on. In general, a complex value.
the ASTM website.
¯ ¯
3
H ,H , etc. = measured transfer function of the acoustic
Available from American National Standards Institute (ANSI), 25 W. 43rd St., 21 31
4th Floor, New York, NY 10036, http://www.ansi.org. pressure signals at location 2 relative to location 1, 3 relative to
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

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E2611 − 09
1, and so on. In general, a complex value. Note that H is valued in general. The following may be useful in evaluating
11
purely real and equal to 1. the defining equations:
I II
H , H = calibration transfer functions for the microphones
jω
e 5 cos ω 1jsin ω
~ ! ~ !
in the standard and switched configurations, respectively. See
~A1jB! 3~C1jD! 5 ~AC1BD!1j~AD1BD!
8.4.
2 2 2 2
c
1/~A1jB! 5 A/~A 1B ! 2 jB/~A 1B !
H = complex microphone calibration factor accounting for
microphone response
...