Meyer Sound Helps Mythbusters Attain Smashing Success
By now, the legion of fans of the Discovery Channel's intrepid "Mythbusters" TV show are well acquainted with Meyer Sound. First, the show's two hosts, Adam Savage and Jamie Hyneman, called on Meyer Sound Staff Scientist Dr. Roger Schwenke to test the urban myth that a duck's quack does not echo (it does). The two returned several months later and fetched Schwenke once more to assist in determining whether or not there is a "brown note:" a low frequency which, when played at sufficient volume, causes "involuntary intestinal motility" in humans. That investigation ended up entailing a dozen modified Meyer Sound 700-HP ultrahigh-power subwoofers and the efforts of John Meyer and several other Meyer Sound staffers. (In case you were wondering, things did not come out in the end.) While the myth was debunked, this experience stimulated John Meyer's interest in exploring extreme low frequency response, which directly influenced construction of Meyer Sound's own recently-completed 57-seat theatre, located at the company's Berkeley headquarters.
Now it's starting to look like Schwenke has become part of the Mythbusters "extended posse," as Savage and Hyneman summoned Schwenke for a third time to test whether a wineglass can be shattered by the human voice. For this recently-screened episode, Beyond Productions, the show's production company, shot in the Meyer Sound theatre.
The story started when Savage and Hyneman were invited to appear on CBS' "Good Morning America" program, where CBS wanted them to test the idea that a glass can be shattered by the human voice alone. The Mythbusters quickly turned to Schwenke, their resident sound guru, for assistance.
Schwenke told the Mythbusters of a heavy metal singer named Jim Gillette, who, as part of his act, regularly shattered glasses with sound. Gillette claimed that he had once done it with his voice alone but had gotten badly cut and so now did it by amplifying his voice through a sound system. Gillette readily disclosed the secrets of how he did it, which the Mythbusters then put to the test in Meyer Sound's anechoic chamber. The technique required the use of a particular brand of glass and placing a board with a two-inch hole in front of the loudspeaker. No board, no smash.
Another interesting technique Schwenke obtained from Gillette was placing a straw in the glass. When a swept tone was put through a Meyer Sound UPA-1P compact wide coverage loudspeaker, the straw would start to move as the resonant frequency of the glass was approached. At the resonant frequency, the straw would stand straight up and "dance." The straw was necessary because the exact resonant frequency, down to a resolution of less than 1 Hz, had to be used in order to break the glass. The straw provided precision exceeding even that of a SIM 3 audio analyzer, motivating Schwenke to add a new feature to the SIM 3 software to allow arbitrary precision from its signal generator.
Having determined the resonant frequency with the straw trick, Schwenke would place the board, play a tone at the determined frequency, and BLAMMO!!
From the anechoic chamber, it was on to "Good Morning America," accompanied by opera singer Genevieve Christianson and Jaime Vendera, a rock singer and vocal coach. Schwenke accompanied the Mythbusters to administer the sound system and, in a pinch, be able to demonstrate that sound could, indeed, break the glass.
In rehearsals, both singers were able to shatter glasses singing through a microphone amplified by a UPA-1P, with Christianson having an especially high success rate. Even during warm-ups before the show, she continued to smash glasses with no problem. In a prime example of the drama of live television, however, when the cameras were actually live, she was unable to break a single glass, but Vendera succeeded once after several attempts.
Now the Mythbusters undertook their own investigation of the idea. Returning to Meyer Sound, they first replicated their earliest experiments, shooting in the Meyer Sound theatre with a high-speed camera that captured in excess of 2,000 frames per second. Following that, the show migrated across the bay to the Castro Theatre in San Francisco, one of the country's few remaining movie palaces.
At the Castro, Vendera once again demonstrated his ability to destroy glasses singing through a microphone and a UPA-1P. Finally, it was time to find out whether a glass could be broken by Vendera's voice alone, without amplification. It took a number of tries but, to everyone's amazement, Vendera was able to achieve – and repeat – the feat.
One mystery remains, however: what's up with the board and the two-inch hole? Schwenke is still pondering this problem, but he's certainly not standing still while he puzzles it out, and is probably not done helping the Mythbusters in their quests. Conversely, the influence on Schwenke of Savage and Hyneman's madcap blend of science and humor is evident as he reports that he has "moved on to researching more robust means of breaking glass using gravity instead of sound."