Author(s): Van Der Linden Petrus J. G. , Morariu Marius C.
The sound power emission of machinery is used for specification of enclosures, barriers and isolation in buildings. And for verification of the actual sound power emission after installation. Determination of the sound power emission in an acoustic chamber, or in free-field are often impossible for large machines, or even for smaller machinery which depends on infrastructure for normal operation. On-site measurements in non-ideal acoustic environments are required. \nThe reference power source method is attractive because of limited complexity and time efficiency and it can be applied even when the acoustic environment is difficult. This paper relates to the reference sound power source method as described in ISO 3741 and later work. \n\nTo improve accuracy and efficiency of this type of measurements, a small and omni-directional reference power source is used. The source is based on a high acoustic impedance loudspeaker, such that it can be placed close to reflecting surfaces. And the internal sensors provide a sound power proportional signal. This allows adaption to the acoustic environment and to potential background noise by using an adapted level and signal type.\n\nA vacuum cleaner was used as a time-stable test-object. Its sound power from three different sites was compared to investigate the reliability of the method and of the prototype sound power reference source.
Name: Mr Petrus van der Linden