australian aboriginal contraption = didgeridoo

>>I just watched an National Graphic program that said that the male lions roar, which is low frequency, can cary over 6 miles or even more (if I remember it correctly) that won't happen with a high pitched voice I'm sure.

As an aside, I believe that the lion on the MGM logo is not "roaring", it is "snarling" - a true lion's roar is much deeper, and the lion does it with its head down. Which makes for much better long-distance communication, but is not as photogenic <img src="images/graemlins/wink.gif" alt="" />

Thanks Baheera,

I stand corrected. <img src="images/graemlins/smile.gif" alt="" /> That's why I keep on reading these posts, you never stop learning here.

After posting something indeed did cross my mind: 'primitive' tribes in Africa used to pass messages through tam tam's (not sure what they're called in English). Some sort of drum (like a small conga?) they place on the ground with legs like a stool that conduct the beats into the soil. And yes, the didgeridoo carries far too.

It makes sense. The problem is - I think - to construct a compact device that produces a low frequency noise with enough power to be usefull. That's probably why high-toned whistles are still so widespread. They're compact and loud.

I once blow a Storm whistle in a shop, which was incredibly loud, but not as high (nor as compact) as a referee's whistle.

Luca

Elephants also communicate with ultra low frequency sounds that travel for miles. Many of the sounds are too low for the human to detect.

Hence the big ears, I suppose?

[Change of Subject]

One of the main functions of the Elephants large ears is the keep cool (large surface area + Rich blood network + flapping motions). [/change of subject <img src="images/graemlins/wink.gif" alt="" /> ]

Actually, I beleive they pick up the vibrations through the ground. Hence the big feet! <img src="images/graemlins/wink.gif" alt="" />

my, my, my .........

Amazing what you can learn on this forum ................
<img src="images/graemlins/grin.gif" alt="" /> <img src="images/graemlins/grin.gif" alt="" /> <img src="images/graemlins/grin.gif" alt="" /> <img src="images/graemlins/grin.gif" alt="" />



Alain

Those are low frequency compared to a Fox 40 whistle.

In Europe they have a two tone siren with a high and a low frequency.
However those vehicles do not necessarily need a siren that carries very far. They need one that stands out, is easy to identify and carries just far enough.
When I used to serve in an emergency team our vehicles siren was blown at about 10 atmospheres. I guess nobody can blow a Fox 40 at a pressure even close to that. So some loss due to the frequency might be affordable.