ULTRARAPID VISUALIZATION AND PRESSURE MEA SUREMENT OF A NONDIRECTIONAL WIDE-BAND ACOUSTIC IMPULSE SOURCE

Ponctual sound sources with very short and simple signature (the ideal beeing a dirac-type) could be very usefull in all the fields of trans ient acoustics. However, such sources cannot be realised by convention nal electroacoustic transducers, because these last cannot be consider ed as point sources and generally have poor transient responses. We pr esent here the solution we have developped, a ''mini-sparker'' which g enerates a very brief acoustic impulse. The characterization of the wa ve emitted is performed both, by ultra-rapid cinematographic ombroscop ic visualisations, and broad-banded pressure measurements.