Thanks for the info! I never thought so much about whistles. Good tip about cupping your hands and blowing it in one direction at a time. I've always carried a cheapo plastic one because it was light weight. One more piece of gear to add to my list…
I did some searching and one reviewer on amazon posted this for the sharx: http://www.amazon.com/review/R2RAI38Y45IYHA/ref=cm_cr_dp_perm?ie=UTF8&ASIN=B0034IUTU6&nodeID=3375251&tag=&linkCode=
"These are the 7 whistles I tested at 1/4 mile distance, over a hill and with general outdoor noise present (birds, wind, etc.), in order of loudness:
1) Storm
2) Fox 40 Classic
3) Acme Tornado 2000 – the "loudest whistle in the world"
4) Acme Tornado
5) Cheap round tubular aluminum whistle.
6) Fox 40 Sharx – on paper, their loudest whistle in decibels
7) Cheap $1.50 whistlecompassthermometer from DealExtreme
I did my test two different ways and then compared the results. First I had my 90 lb. son blow each whistle 3 times while I listened from 1/4 mile away, over a small hill. We could not see each other, but we used walkie talkies to communicate. Then we traded places and repeated the testing. We both wrote down our scores which were based on how loud we perceived each whistle, and we did not show them to each other until all testing was done. Here were the results:
We both rated the Storm to be the loudest, easily.
We both rated the Fox 40 CLASSIC to be the second loudest.
We both rated the Acme Tornado 2000 to be the third loudest.
The remaining 4 whistles were not significantly different from one another and none of these 4 were even close to the top 3, with the exception of the Acme Tornado which, to my ears, was rated the fourth loudest. Not surprisingly, both the cheap whistles were barely heard, but VERY surprisingly, the Fox 40 Sharx was no louder. In fact, my son actually rated the cheap aluminum whistle to be just a bit louder than the Sharx. I rated them the same.
The biggest surprise was the Fox 40 Sharx, which was among the quietest of the bunch. And here is the irony. Up close, the Sharx was, by far, the most ear-piercing, even more than the Storm. Hence the reason you can't do close up tests for whistles. The pitch of the whistle is just too misleading up close, and they simply do not carry over a distance the way you would think.
Conclusion: If you want a real "life saver" from a distance, choose the Storm. If it's too big for your taste, choose the Fox 40 Classic. The Acme 2000 would be a runner-up. Throw the rest away or give them to your little children to play with. At 1/4 mile they are barely heard.
I hope this was helpful to somebody. "