Well yeah, the darn pea in the pea whistles used to freeze up and then they would be hard to get any sound out of at all.
The metal ones would freeze to your lip too if you were not careful.
I remember carrying the metal pea whistles in my inside parka pockets so they would stay warm enough to work and not tear pieces of my lip off.
The plastic Fox whistles were a huge improvement.

Interesting, I have always wondered why survival whistles have become so high pitched over resent years. Especially as it has been know for around 100 years that low pitched sound travels a lot further than high pitched.

This was shown in a very practical test when researching the improvements of nautical sound signals and foghorns. I don't remember the chaps name but he had a piano placed on a beach and different notes played whilst he sat in a rowing boat seeing which note was heard the furthest. He reported that the low notes could be heard the furthest and this was adopted for use in foghorns.

You can generate a lot more audio power at higher frequencies in a smaller package. (That's why double base players are never popular in a marching band).

I guess a Fox40 mini is easier to carry than a basoon!
A high pitched noise probably also stands out better against any background, the sea in fog is relatively quiet.

Although sound travels better in a moist atmosphere, fog is to dense so absorbs sounds, especially high pitched sounds.

I have lived by the sea all my life and within hearing distance of foghorns including the Portsmouth harbour entrance marker horn and the Bristol Channel navigation horn which can be heard at 46 mile minimum distance. Just because it is foggy it does mean it is relatively quiet, the sound is absorbed so it is perceived as being quieter, the foghorn has to be able to cut through that effect.

If you read the article and other articles about sound waves you will understand that long soundwaves travel around and often through obstacles far better than short soundwaves this point to the fact that low frequency sound is less disturbed and distorted by the environment than high frequency sound allowing it to travel further. This can be heard on wide band radio.

I recognise that to produce low frequency sound you need a larger chamber than high frequency sound. My point is manufacturers are kidding themselves by making louder whistles with higher frequency sounds instead of increasing the efficiency of lower frequency whistles. The fact is the manufactures are going against hard scientific fact and misleading people with their sales pitch in the process.

My original post was reflecting on why manufacturers feel the need to do this. the reason is the average person does not understand the process of sound so they perceive that a loud high pitched ear bleeding sound is more effective when they blow a whistle than one with a lower pitched sound, using our own failings in hearing to mislead use, probably through the lack of understanding, of which is the best sound.

A well researched and engineered whistle at 70dB would be far better than one at 105dB. This is borne out by the human voice compared to the storm whistle.

Fascinating article.

I found it very interesting that the Coghlan's whistle I bought "until I get a better one" turns out to be one of the best performers. Guess I won't be replacing it after all.

(I also have a Storm in my GHB, and the Fox Micro in the AMK PSK in the GHB.)

Also interesting that the metal survival whistle that came with another PSK I was given is the lowest performer of the bunch. Well, I put it on my keychain for more mundane whistling, so that's not a problem.

This was certainly an interesting article but it failed to recognise one simple fact.

The study did find that louder whistles can be heard at greater distances.

But the study failed to take into account that louder whistles take more effort by the person producing the puff to make that louder sound.

In a search, the person blowing the whistle will tire more quickly whilst blowing the louder whistle than the quieter one hence reducing the probability of a search party hearing the whistle. This was not factored into the results.

I'm sure thats true.
My point was that a higher pitched sound might attract more attention against background noise than a lower one.

I suspect that whistles are now so common that any other sound wouldn't work as well. If I heard a whistle in the woods I would assume that somebody needed help whereas an air horn I would guess was some construction work, forestry etc.

Interesting article. You would think that someone might come up with different whistles that would be suitable for different situations, rescue for one, job site for another, instead of one-size-fits-all sort of thing. Like flashlights.

It appeared that they measured the distance of the sound in feet, if I was reading it correctly. Elephants communicate with infrasonic rumbles that are so low that humans can't always hear them even when they're nearby, but other elephants will pick up the 'message' over two miles away.

Sue

Very true Susan, if i remember correctly forest elephants in fact communicate much further than two miles using this method.

In the jungle a whistle is next to useless. The best way to communicate over long distance is to drum on the buttress of the silk cotton tree. This gives of a deep low frequency sound that cuts through the jungle for quite considerable distances.

Another problem with high frequency sound is because it has such a short wavelength it is reflected of of obstacles a lot more so although it might stand out over other noises a little bit better it is a lot harder to determine the direction it comes from. we experience this when we first hear emergency vehicle sirens.

Great to have actual measurements of the practical range of my whistles.... (or voice for that matter, I have a pretty strong voice, but I can't shout at maximum for more than just two minutes before I have to lower the volume or go completely hoarse).


From their charts I deduce that I shouldn't expect people to notice my whistle at 500 meters (unless perhaps in favorable conditions) ... but at 200 meters there's a pretty good chance they will notice. In my book, that's great to know.


200 meters doesn't seem as much, but it is in fact quite some distance in the woods. Lots of people can be in a 200 meter (600 feet) radius and you won't even notice them. If there's a trail within 200 meters, people on that trail should be able to hear you.


To increase that range - does anyone have ideas of how to improvise low frequency sound devices? A makeshift drum is obvious, but perhaps there is some other techniques for squeezing low/medium frequency sounds out of some garbage or equipment? I don't think a drum will attract much attention beyond "curse that hippie, he can't even play". Hopefully, if you bang long enough someone will turn up to tell you to keep quiet.