Dual Tone Emergency Whistle

thingiverse

I tried a lot of whistles, including the famous V2 that claims to be really loud. However, I noticed that a really high pitch is not always that audible at a distance or in a loud enviroment. But the most annyoning thing for me was that basically all whistles required a massive blow to produce any meaningful sound. If in a real emergency this might be a problem. My whistle uses a very low and a very high pitched sound. Even with just a little bit of air there is already a noise and if you blow hard it gets quite loud too. I won't make any claims about the decibels it can reach as destroying my eardrums was not part of the testing but I guess it should be loud enough ;) The two tones are closely matched in their harmonics so if you blow hard the resulting sound will be quite annoying - but audible at a distance.