DS/ISO 6926:1992 Acoustics. Determination of sound power levels of noise sources. Requirements for the performance and calibration of reference sound sources
1 General
This International Standard specifies the essential acoustical performance requirements of reference sound sources.
It specifies procedures for calibrating a sound source intended for use as a reference sound source in terms of its sound power levels in octave and one-third octave bands and with frequency weighting A.
To achieve uniform and accurate results, this International Standard requires Ihat the calibration be performed in the acoustic environment provided by a hemi-anechoic room, i.e. a free field over a reflecting plane. The reference sound source operates on the reflecting plane and radiates sound into the free field above the plane.
It specifies the detailed procedures necessary to achieve the estimated calibration uncertainty given in table 1.
This International Standard applies to a sound source which is manufactured for use as a reference sound source.
2 Measurement uncertainty
Calibration of a reference sound source, when carried out in accordance with this International Standard, is expressed in terms of the sound power level of the source while it is radiating into an acoustic free field above a reflecting plane. Determination of the sound power levels of a reference sound source, when made in accordance with this International Standard in several laboratories, tends to result in standard deviations which are equal to or less than those given in table 1. The standard deviations of table 1 take into account the cumulative effects of all
causes of measurement uncertainty. The A-weighted sound power level is determined with a standard deviation of less than 1 dB.
NOTES
3 The standard deviations listed in table 1 are measures of the uncertainties associated with the test methods defined in this International Standard. If a particular reference sound source were to be transported to each of a large number of laboratories, and if, at each laboratory, the sound power of that source were measured in accordance with the provisions of this International Stan dard, the standard deviation, as a function of frequency, of these many sound power determinations could be calculated.
4 If a similar round robin series of measurements were to be carried out on each of a large number of other reference sound sources, this procedure would correspond to the random selection of a sound source and the random selection of a laboratory. It is not these standard deviations that have been estimated and are listed in table 1. The uncertainties given in table 1 apply only to the particular source that is being calibrated. The calibration of a particular reference sound source does not apply to another reference sound source of the same design and manufacture unless statistical data are available to specify the additional uncertainty introduced by product variability.
DS/ISO 6926:1992 history
2001DS/EN ISO 6926:2001 Acoustics - Requirements for the performance and calibration of reference sound sources used for the determination of sound power levels
1992DS/ISO 6926:1992 Acoustics. Determination of sound power levels of noise sources. Requirements for the performance and calibration of reference sound sources
DS/ISO 6926:1992 Acoustics. Determination of sound power levels of noise sources. Requirements for the performance and calibration of reference sound sources was changed to DS/EN ISO 6926:2001 Acoustics - Requirements for the performance and calibration of reference sound sources used for the determination of sound power levels.