1、Designation: E 1179 87 (Reapproved 2003)Standard Specification forSound Sources Used for Testing Open Office Componentsand Systems1This standard is issued under the fixed designation E 1179; the number immediately following the designation indicates the year oforiginal adoption or, in the case of re
2、vision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) 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
3、 between openoffices or for measuring the laboratory performance of acous-tical components (see Test Methods E 1111 and E 1130).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 qua
4、lifying it using a special qualification signal. Testsignals required by open office test methods may differ.2. Referenced Documents2.1 ASTM Standards:C 384 Test Method for Impedance and Absorption ofAcoustical Materials by the Impedance Tube Method2C 634 Terminology Relating to Environmental Acoust
5、ics2E 1050 Test Method for Impedance and Absorption ofAcoustical Materials Using a Tube, Two Microphones, anda Digital Frequency Analysis System2E 1111 Test Method for Measuring the Interzone Attenua-tion of Ceiling Systems2E 1130 Test Method for Objective Measurement of SpeechPrivacy in Open Office
6、s Using Articulation Index22.2 ANSI Standards:S1.4 Specification for Sound Level Meters3S1.6 Preferred Frequencies and Band Numbers for Acous-tical Measurements3S1.11 Specification for Octave, Half-Octave and One-ThirdOctave-Band Filter Sets33. Terminology3.1 Definitions:3.1.1 The acoustical termino
7、logy used in this specificationis consistent with Terminology C 634.3.2 Descriptions of Terms Specific to This Standard:3.2.1 qualification signala test signal of broadband noiseor bands of white or pink noise as defined in TerminologyC 634.3.2.2 source pointthe point at which the loudspeaker axisin
8、tersects the front plane of the loudspeaker (see Fig. 1).4. Sound Source Specifications4.1 Sound Source Description4The sound source shall bea loudspeaker enclosed in a box that has a maximum dimensionof 0.30 m (1 ft) on a side, to reduce spurious sound reflections.4.2 DirectivityWith the source dri
9、ven with the qualifica-tion signal, the maximum and minimum sound pressure levelswithin any one-third octave band, measured at a distance of 1.0m (39 in.) from the source point, at any angle up to andincluding 25 in any direction from the loudspeaker axis, shalldiffer by 2 dB or less.NOTE 1At angles
10、 beyond 25 from the loudspeaker axis, the sourceshall produce lower levels than within the 50 included angle.NOTE 2The 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 Tes
11、t EnvironmentThe measurements shall be carriedout in a free sound field. The preferred test environment is ananechoic room with surfaces that have a minimum normalincidence sound absorption coefficient of 0.990 at all frequen-cies above 175 Hz as measured in accordance with TestMethods C 384 or E 10
12、50. Alternatively, an outdoor environ-ment may be used if it is shown that sound reflections do notinfluence the data.5.2 Test Instruments:5.2.1 The measurement microphone, amplifier, and levelmeter used to measure sound pressure levels shall satisfy therequirements of ANSI S1.4 for Type 1 or better
13、 sound levelmeters except that weighting networks are not required.1This specification is under the jurisdiction of ASTM Committee E33 onEnvironmental Acoustics and is the direct responsibility of Subcommittee E33.02 onOpen Plan Spaces.Current edition approved Aug. 10, 2003. Published September 2003
14、. Originallyapproved in 1987. Last previous editionapproved in 1998 as E1179 87 (1998).2Annual Book of ASTM Standards, Vol 04.06.3Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036.4A sound source available from Acculab, 3201 Ridgewood Dr., Colu
15、mbus,OH 43220, (or its equivalent) has been found suitable for this purpose.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.2.2 A free field microphone shall be used, that is, one thathas its flattest frequency response for sounds
16、arriving normal tothe diaphragm.5.2.3 One-third octave filters shall meet the requirements ofANSI S1.11 for Class III, Type R or Type E filters.5.3 Qualification Sound OutputWhen the sound source isdriven with the qualification signal, the sound output shall beadequate to maintain one-third octave-b
17、and sound pressurelevels at least 10 dB above the corresponding background noisein each band at each measurement location.NOTE 3Sources which produce an A-weighted sound level of 70 to 90dB at 1 m (3.3 ft) when driven with broadband noise usually meet thisrequirement.NOTE 4The background noise consi
18、sts of the ambient noise and theinternal noise of the measuring instruments, as defined in TerminologyC 634.5.4 Directivity MeasurementThe directivity of the soundsource shall be verified by driving the source with thequalification signal and measuring the sound pressure levels atmeasurement points
19、that include those shown in Fig. 1. Forthese measurements, the axis of the microphone shall beoriented along the line from the measurement point to thesource point with the microphone diaphragm facing the source.This shall be carried out at each one-third octave-band pre-ferred center frequency from
20、 200 to 5000 Hz in accordancewith ANSI S1.6. At a minimum, the data shall be obtained atseven measurement points in each of two perpendicular planes,such as the horizontal and vertical planes, at a distance of 1 m(3.3 ft) from the source point.5.5 It is recommended that the source be qualified in th
21、ismanner on an annual basis.6. Qualification Report6.1 A report shall be made available providing the qualifi-cation test data for sources that meet this specification.7. Keywords7.1 loudspeaker; open office; open office components; openoffice components and systems; sound; sound source directiv-ity
22、; sound sourcesASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of s
23、uch rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for add
24、itional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to t
25、he ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).FIG. 1 Measurement Points for Sound Source DirectivityE 1179 87 (2003)2
