Investigations on the Suitability of an electroacoustic Sound Source as secondary Sound Power Standard

The aim of the European project "EMRP JRP SIB 56 SoundPwr" is the realisation, dissemination and application of the unit "watt" in acoustics on the basis of a primary sound power standard. One partial task is to develop a secondary standard for sound powers with tonal components. In addition to a uniform directional response pattern, the measurement of the generated volume flow should also be possible. Eventually, the decision was made in favour of a commercially available electroacoustic sound source which is designed for measurements in room acoustics. The advantage of an electroacoustic source is that, in principle, arbitrary signals can be emitted. In addition, an adapter is available for this sound source which allows the direct measurement of the generated volume flow. For an electroacoustic sound source, however, the question of linearity and long-term stability always arises. Furthermore, no practical experience has so far been available for the use of the volume velocity adapter. In addition, the question arises as to whether the sound source can be used in a hemi-anechoic room as a ground-level point source. Against the background of these questions, the sound source has been comprehensively tested, and the results obtained are presented.