Where to start... the climax is completely unbelievable, but maybe that's the point. Maybe he's just a terrible lier and we're not supposed to believe his story, in which case why does Jim?
This tuning fork is subsonic and vibrates at 32.8Hz. In order to vibrate less than 33 times a second that tuning fork would have to be much bigger. Why did they need to use a dragonfly to determine the source of the sound? Wouldn't a directional microphone hooked up to an oscilloscopebe a significantly better way? Not to mention that if I wanted to produce a sound at a specific frequency I'd use a computer instead of producing number of tuning forks until I found the frequency.
Despite the obvious scientific flaws (does this show not have a science consultant?) it's possible that what I see as bad writing is just incredibly bad directing. The writer Jose Molina is noamateur, in fact he wrote two of my favourite Firefly episodes. However director Bryan Spicer is no greenhorn either, though in his case none of his previous credits jump out at me as particularly noteworthy.
I'll continue to watch for the time being, but if the next two or so episodes aren't significantly better than this one I don't think I'll be coming back for more.