On Friday, July 10, 1998 at 12:00:00 AM UTC-7, Billy Newsom wrote:   
   > I heard that the French once made a device that could kill a man at some   
   > terrific distance (a few km) using sound energy.  The tuned phased array   
   > of speakers would generate 7 Hz in a highly directional beam.  It was   
   > powered by a jet engine.  (I made up the power output of the weapon --   
   > it could be a few MW, dunno.)   
   >    
   > Hmm, I wonder if the weapon had a mean side lobe.  It would kind of suck   
   > if people 90º or 60ºoff-center were frying.   
   >    
   > Anyway, the weapon works by air (sound) pressure.  I think the   
   > theoretical maximum is 194 dB, at which point the sound pressures will   
   > alternate between 0 and 2 atm.  Doing the math, if a speaker array   
   > produced 190 dB at 1 m, the sound power should be 124 dB at 2 km (-20 dB   
   > for every tenfold increase in distance).  This type of energy at 7 Hz is   
   > supposedly enough to break walls, kill trees, and shatter windows.  I'd   
   > guess that the weapon is unfeasible mainly because of the large amount   
   > of power needed, and the way it will shred anything in the path --   
   > people, cats, cars, buildings, etc.   
   >    
   > Although I'd heard of death rays in movies, I haven't heard of many   
   > actual death rays.  I wonder if "Le Monstre" is as good or better than   
   > laser death rays?   
   >    
   > Billy "them Hertz hurts" Newsom   
      
    The device used several 78 foot nlong tubes to make the low frequencies   
   become more directional, nsince anything less than about 45 hz. becomes ve3ry   
   omnidirectional. High frequencies on the other hand, are highly directional.    
   You are correct the    
   theoretical maximum spl nis around 194 db! to get that loud you would need 50   
   pounds of dynamite.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)