Work package 1: Realisation of the unit watt in airborne sound

Work package 1 is focused on a primary standard for the realisation of the unit watt in airborne sound. It will be based on a vibrating baffled solid body. The sound power output of this device can be determined from the vibration velocity of the body’s surface and several additional quantities like static pressure and temperature. In particular, measurements in the airborne sound field as well as restricting assumptions on the nature of the sound field are not required. An uncertainty of 0.5 dB for the realisation of the unit watt is thus aimed at.


Work package 2: Dissemination of the unit watt in airborne sound

The objective of this work package is to develop a system for the dissemination of the unit watt using appropriate transfer standards. It will be investigated whether existing aerodynamic reference sound sources may serve as transfer standards. Furthermore, a tonal transfer standard will be developed and tested. The uncertainty of the sound power emitted by the transfer standards will be determined. The aim is that this uncertainty is only slightly larger than the uncertainty of the primary standard.


Work package 3: Application in machinery noise

The key issue of this work package is the application of the transfer standards in machinery noise. One application to be developed is the qualification of complete measurement setups for sound power determinations. These setups are combinations of the acoustic field properties and the measurement equipment. The determination of the sound power of real sources by comparing them to a transfer standard is another application aimed at. Here, the determination of the uncertainty of the sound power is a major topic.