by 13 Stoploss
Tonight, I was testing my ribbon tweeters in the ESS AMT Monitors. I put a CD into the player and cranked the volume to about -11 in 2 channel Stereo mode (a piece by Gyorgy Ligeti played by Dominic Harlan). I started with both channels, then just the right channel, and finally, just the left channel. At about -19, the left ribbon was distorting and tingling. The right had no such problem all the way to -11. I went back to both channels, at the same volume. I heard something in the cabinets, which are about 12 feet away in a perpendicular line from the left speaker (the tweeters are dimensional to 360 degrees). I didn't think anything of the noise, just that maybe I was hearing things since the volume was so loud. About two hours later, a mixing bowl in the cupboard had burst. It was not freestanding, but neither did it have the weight or pressure of a larger bowl on top of it. In fact, it had a smaller glass mixing bowl inside it. The dimensions of the small bowl did not touch the sides of the larger bowl, just the bottoms, one inside the other. The bowl that shattered was sitting on top a thicker glass pie bowl. Here is the result:
Mrs. 13 is not happy.
The ESS AMT Monitor is the flagship model from former California brand ElectroStatic Sound. Dr. Oskar Heil, a German scientist, is credited with the patent for the "Heil Air Motion Transformer." Details on the air-motion transformer can be found at Wikiepedia, and at the ESS Web Archive.
The top woofer measures 12" and the bottom woofer, a passive radiator, also 12", helps to move air for impressive bass response. They can handle a maximum of 400W at 6 OHMS and have a sensitivity or efficiency rating of 93db, and a frequency response of 30Hz-23Khz. Each tower weighs 110 pounds, and when combined with a audiophile quality receiver and amp, they will murder your ears.