160 dB at 16Hz

[CECAA850]

As many of you know, Tom Danley was involved in designing sonic boom generators for the US gov't.

Here is a post he put on the AVS Forum last Fall. I have a hard time imagining 165 db at 4.5 Hz. Talk about guts turning to Jello.

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I had designed a couple sonic boom simulators in the past so I can answer your question.

A typical sonic boom is what they call an N wave, it starts with a VERY rapid rise to some peak value, then it has a nearly straight line decay past zero to some peak negative value, with a rapid return to Zero (with some ringing).

The lowest frequency component is related to the speed and length of the plane, a longer plane makes a lower Fundamental at the same speed as a shorter one.

A sonic boom has a distinct sound, a very definite KAAA BOOOM, you hear the fast rise and fall as two events. Airplanes actually make a great deal of noise going fast but I would doubt if they were supersonic as the sound would break windows for a long way and given a lot of foot ball fans a critical bathroom related cloths problem at a minimum.

Aboard aircraft carriers there is a ritual where one flys by the ship at mach, it is so intense that few actually choose to be on deck, although I know I would have to try it.

On our web site is a clean photo of a jet doing a carrier flyby at mach. What you cant see is the pressure wave, which is in front of the white condensation that a low pressure produces.

Danleysoundlabs.com

In the systems I built, the intention was testing ground level sound from aircraft.

The sealed system (a sealed bunker thing) used 27 of the ConraBass style motor systems (no passive radiators) and could produce 165 dB down to 4.5 Hz which is enough to break windows and doors etc (the intention of the project was to classify building stuff I think).

The other system, much harder was to expose the exterior of a house to the sonic boom from the NASA space plane. It would be much higher in the air BUT produced a much lower frequency signature. Add that to the fact it is 2 meters away from the house wall and outdoors, made it a project from hell. That system could produce 132 dB on the house wall, from 5KHz down to 3 Hz. The lower range (30 Hz to 3Hz) was handled by large low pressure flow modulators and required its own 50KW 3 phase service to run.

Anyway, thats what I can tell you about it.

Dont get any ideas about a home unit.

Best,

Tom Danley

Danley Sound Labs

I have no idea why, but.............I want one.

[Jay481985]

Me too!