ASTM_E_1179_-_13.pdf

Designation:E117913Standard Specification forSound Sources Used for Testing Open Office Componentsand Systems1This standard is issued under the fixed designation E1179;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This specification states the requirements for soundsources used for measuring the speech privacy between openoffices and for measuring the laboratory performance ofacoustical components(see Test Methods E1111 and E1130).1.2 The sound source shall be a loudspeaker located in anenclosure driven with an appropriate test signal.1.3 This specification describes the sound source andmethod of qualifying it using a special qualification signal.Testsignals required by open office test methods may differ.1.4 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.2.Referenced Documents2.1 ASTM Standards:2C384 Test Method for Impedance and Absorption of Acous-tical Materials by Impedance Tube MethodC634 Terminology Relating to Building and EnvironmentalAcousticsE1050 Test Method for Impedance and Absorption ofAcoustical Materials Using a Tube,Two Microphones anda Digital Frequency Analysis SystemE1111 Test Method for Measuring the Interzone Attenuationof Open Office ComponentsE1130 Test Method for Objective Measurement of SpeechPrivacy in Open Plan Spaces Using Articulation Index2.2 ANSI Standards:3S1.4 Specification for Sound Level MetersS1.6 Preferred Frequencies,Frequency Levels,and BandNumbers for Acoustical MeasurementsS1.11 Specification for Octave Band and Fractional OBAnalog and Digital FiltersS1.43 Specifications for Integrating-Averaging Sound LevelMeters2.3IEC Standards:461260 ElectroacousticsOctave and fractional-octave bandfilters616721 ElectroacousticsSound Level MetersPart 1:Specifications3.Terminology3.1 Definitions:3.1.1 The acoustical terminology used in this specificationis consistent with Terminology C634.3.2 Definitions of Terms Specific to This Standard:3.2.1 directivity measurementthe measurement used todetermine directivity as defined in 4.2.3.2.2 qualification signala test signal of broadband noiseor bands of white or pink noise as defined in TerminologyC634.3.2.3 source pointthe point at which the loudspeaker axisintersects the front plane of the loudspeaker(see Fig.1).3.3 The following terms in this standard have specificmeanings that are defined in Terminology C634:3.3.1 background noise,3.3.2 pink noise,3.3.3 sound pressure level,and3.3.4 white noise4.Sound Source Specifications4.1 Sound Source DescriptionThe sound source shall be aloudspeaker enclosed in a box that has a maximum dimensionof 0.30 m on a side.4.2 DirectivityWith the source driven with the qualifica-tion signal,the maximum and minimum sound pressure levelsof any one-third octave band,from 200 to 3150 Hz measured1This specification is under the jurisdiction of ASTM Committee E33 onBuilding and Environmental Acoustics and is the direct responsibility of Subcom-mittee E33.02 on Speech Privacy.Current edition approved Aug.1,2013.Published October 2013.Originallyapproved in 1987.Last previous edition approved in 2011 as E1179 11.DOI:10.1520/E1179-13.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3Available from American National Standards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY 10036,http:/www.ansi.org.4Available from International Electrotechnical Commission(IEC),3,rue deVaremb,P.O.Box 131,CH-1211 Geneva 20,Switzerland,http:/www.iec.ch.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 at a distance of 1.0 m from the source point,at any angle up toand including 25 in any direction from the loudspeaker axis,shall differ by no more than 2 dB.At frequencies above 3150Hz,the difference shall be no more than 3dB.NOTE1At angles beyond 25 from the loudspeaker axis,the sourcemay produce lower sound pressure levels than within the 50 includedangle.NOTE2The directivity requirement may be met by using more thanone loudspeaker,each one used separately to cover a different portion ofthe test frequency range.5.Source Qualification5.1 Test EnvironmentThe measurements shall be carriedout in a sound field,essentially free of acoustical reflections.The preferred test environment is an anechoic room withsurfaces that have a minimum normal incidence sound absorp-tion coefficient of 0.990 at all frequencies above 175 Hz asmeasured in accordance with Test Methods C384 or E1050 or,by the use of other methods,can be shown to be essentiallyanechoic between 200 Hz and 5000 Hz