[sdiy] About infrasounds

[Magnus Danielson]

From: harry <harrybissell at prodigy.net>
Subject: Re: [sdiy] About infrasounds
Date: Sun, 21 Apr 2002 23:43:43 -0400

> Grant Richter wrote:
> 
> > Infra sound of sufficient power and at the resonant frequency of the thorax
> > is reputed to be able to cause cavitation based hemorrhages. In other words,
> > the pressure extremes in your body at resonance may cause blood clots, which
> > may cause stroke or heart attack.
> 
> <snip>
> 
> In the mean time... the audience will just WISH they were dead....  ;^P

<not all that serious>
Now... why the hell have not Death-metal band come up with that yeat?
Boy, they are wimps when they do not take it to the extreme...
</not all that serious>

> H^) harry
> 
> I had an experience with this once... it was a very loud band (mine) in a
> small practice room... and I just happened to be standing in a corner at the
> focus of some low frequency standing waves...
> 
> It made me dizzy and sick.  I had to stop the band. I finally
> realized what was happening and told them. The drummer insisted I
> was "full of shit" so I told HIM to go walk into that corner while
> we kept playing.  He turned around with an expression of total
> shock... "Wow... its like going underwater, I can't believe it..."
> 
> so we turned down after that...

Ah... another joke there is that "after staying here sufficiently long
I will not be full of shit anymore...".

Now... how do you get your PA to pull this stunt?

A good tip is to use Servodrive speakers. You *MUST* have a lowpass
filter to cut of higher energy. I know people who broke their Servo's
since they tossed in high energy of higher frequency. It varies with
model, but one number is 125 Hz. The Servodrive speakers will live
happy in a cluster together, preferably with as much floor and side
baffles around as possible.

Cheers,
Magnus - shake that body!