Abstract This specification states the requirements for sound sources used for measuring the speech privacy between open offices or for measuring the laboratory performance of acoustical components. The sound source shall be a loudspeaker enclosed in a box that has a maximum dimension of 0.30 m (1 ft) on a side, to reduce spurious sound reflections. The measurements shall be carried out in a free sound field. The measurement microphone, amplifier, and level meter used to measure sound pressure levels shall satisfy the requirements prescribed. When the sound source is driven with the qualification signal, the sound output shall be adequate to maintain one-third octave-band sound pressure levels at least 10 dB above the corresponding background noise in each band at each measurement location. The directivity of the sound source shall be verified by driving the source with the qualification signal and measuring the sound pressure levels at measurement points. Scope 1.1 This specification states the requirements for sound sources used for measuring the speech privacy between open offices and for measuring the laboratory performance of acoustical components (see Test Methods E1111 and E1130). 1.2 The sound source shall be a loudspeaker located in an enclosure driven with an appropriate test signal. 1.3 This specification describes the sound source and method of qualifying it using a special qualification signal. Test signals required by open office test methods may differ. 1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
