BG>  You make some excellent points about loudness. The highest I've ever
 BG> subjected myself to intentionally was 130dB of pink noise for room
 BG> tuning. That was to stress test a finished sound system to make sure it
 BG> Now that is damned loud, unreasonably loud, uselessly loud.
Could you picture simulating the loudness of a NASA launch pad?  B&K says the 
mics they sell NASA for that are spec'd to handle 180 dB before overload.  
I can picture how one could make "headphones" with coupled pairs for each 
side of larger compression drivers and achieve around 170 dB at the ears, but 
what kind of array would one need to produce 180 dB across a spectrum from 
subsonic on up?  
OTOH, at 130 dB, square waves swept from 1.5 to 5 kHz at a rate of about 11 
cps could be pretty disruptive to human ability to function.  Much easier to 
generate than equivalently disruptive levels of low frequencies, but also 
easier for "victims" to protect themselves, so long as they could have both 
hands free as 'earplugs'.  At that kind of pattern, it only takes about 0.05 
W into a couple of cheap piezo tweeters to drive most people running from 
large home or office size rooms.  
 BG> I've noticed government people with SPL meters and a number of concerts
 BG> locally, one for an outdoor venue that had been operating for years
 BG> before a housing development sprung up almost next door to it, and now
 BG> the people in the houses are bitching about the volume, so the venue
Sounds like one situation in CT, but where the venue is close enough to the 
town line so that neighbors over the line can't effectively play nasty with 
zoning laws.  They have to accept state "health" regulations and deal with 
it.  There's also one airport nearby around which houses were built and 
bought, and residents then complained they didn't want planes landing or 
taking off.  That makes about as much sense as those who buy intended 
disposable summer cottages on a flood plain or barrier island and complain 
the government has some obligation to protect them when such buildings are 
converted to year round residences.  
 BG> Now if an audience level of 115dB is still about say 100dB at the
 BG> houses, image how bad 155 dB would be going down your street.
I'd assume that 155 dB value has to be based on a highly reflective closed 
chamber that can be pressurized, and not a value that holds up without rapid 
loss when subjected to free space.  
-> Didn't the Germans play around with low frequency horns during WW2,-> 
apparently a frequency of around 7Hz has pretty nasty effects on the
 BG> A device known as an "acoustical laser" was invented by them and could
 BG> have been a major factor if used in against a large group of men on a
 BG> battlefield. Basically it is two very high powered ultrasonic drivers
Do you recall what kind of audio levels or frequencies that generated?  
 BG> I used 14Hz to great effectiveness during a production of Dracula we did
 BG> in college. Before Dracula would appear I would put some 14Hz through
Cute!  
Terry
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