Vibration testing apparatus and method using acoustical waves

A vibration testing method comprising the steps of:

• a) providing an acoustical insulation chamber containing first and second acoustical transducer means facing one another, said first and second acoustical transducer means being characterized by complementary frequency operating ranges;
• b) securing at least one article to be tested in a position between said acoustical transducer means within said chamber;
• and
• c) driving said first and second acoustical transducer means with corresponding first and second electrical output signals to cause generation of acoustical waves for imparting vibration to said article, said first and second output signals having respective complementary frequency spectrums adjacent a crossover cutoff frequency and being substantially in opposed phase relationship in the area of the crossover cutoff frequency.

A vibration testing method comprising the steps of:

• a) providing a main enclosure defining a main acoustical cavity and having a baffle provided with at least one main opening;
• b) disposing at least one article to be tested in a position where said main opening is substantially closed by the article to expose a surface thereof to acoustical waves of low frequency range while attenuating the portion of the acoustical waves reaching a substantially opposed surface of said article which is not directly exposed to the low frequency acoustical waves;
• and
• c) generating acoustical waves within a low frequency spectrum toward said opening and said at least one test article.