There is something wrong with the 37.5 kHz ping discoveries.
Quote:
Australian search authorities said on Sunday a Chinese patrol vessel, the Haixun 01, had
picked up a fleeting "ping" signal twice in recent days in waters west of Perth, near where investigators believe Malaysia Airlines Flight MH370 went down on March 8.
More planes and ships were being sent to assist in that area, but meanwhile, Australia's HMAS Ocean Shield had reported a
separate "acoustic event" some 300 nautical miles away.
http://www.nydailynews.com/news/world/sh...ticle-1.1747367
Here is a potential explanation:
Quote:
The 37.5 kHz frequency is outside the audible spectrum for the human ear.
Acoustic hydrophones ‘translate’ the signal into the audible spectrum, a
process which does not exactly reproduce the original emission, which can be
‘polluted’ by the water environment and thus misprocessed.
[...]
With such faint signals, difficulties may also be experienced when sounds emitted by
the biological environment (eg whales)confuse the acoustic devices. Cetacean sound emissions typically take the form of swift ‘chirps’ over a wide spectrum of frequencies, which could at times be perceived as a short regular pinger signal, after being sampled and processed by acoustic devices.
http://www.azi.hr/docs/ACC_GuidelinesWeb%5B1%5D.pdf