HyperWhistle is claimed to be the world's loudest whistle, and I don't plan on having someone blow one in my ear to test it. The pitch is high and timely. It even works underwater. We promise that our ...

I've never been particularly effective at whistling. Some people can't whistle -at all-, I produce a shallow 'blowy/breathy' whistle, which has about 1/4 of an octave range. That article describes the ...