Etalonnage des intensimètres. Applications industrielles

Abstract
The determination of Sound power levels of machines using acoustic Intensity techniques is an interesting method. To obtain a high accuracy, it is necessary to reduce the phase mismatch of the microphones. The usual solutions are physical matching of the microphones (matched probe) or the use of calibration procedures to eliminate the phase mismatch of the two channels. Theoritically, using a good matching probe, acousticians do not need to use calibration procedures. However, at industrial sites, measurement systems were usually submitted in heavy conditions (environments, transport, etc...). It is therefore necessary to check their quality before use. AKSUD and CETIM have developped a tested and easily used system : special, matched intensity probe and a on-site calibrator. The principal advantage of this system is based on the simplicity procedures. In fact, in the classical calibration method, operators need to take the microphones off the probe assembly during the use of electrostatic excitation components. With these new products, the probes are built with an electrostatic component. The calibration will be processed without removing the microphones from the assembly. In this way, the calibration procedures are easier to be repeated more frequently. Today, with this new system (probe and on-site calibrator), acousticians have an efficient means of control of probe quality to ensure good measurement results.