The Fox Comparison Table of the Fox Whistles has the Sharx at 120 dB and the Storm whistle brochure claims 130 dB for the Storm.

Getting 130 dB out of the Storm may take some work, though. The 2008 Whistle Test Part 2 commented that, while the Storm was "easy to blow", it "required more airflow". The Storm results in that test were 120.6 dB adult average, 111.6 dB child average, 102.6 dB "tester with lung condition average".

Since that test rated other whistles "very easy to blow" vs. the Storm "easy to blow", it seems to me some other whistles might come out louder when blowing them for hours. Since the TOPS KNIVES whistle was rated "very easy to blow" and 123.6 dB adult average in the test above, and "field test 126 dB" on the TOPS site, it seems worth exploring.

One blowing tip for the Sharx is to wrap your lips around it, rather than pressing them against it.

Since the Fox Sharx did not come out until 2010, it was not in the 2008 test.

With the Sharx, I've seen several comments ( Amazon review , SOCAL Hiker Lady Review ) about ear pain/ringing, and recommendations to cover your ears when blowing them. (Something to consider with all of these loud whistles).