forestcreature
Well-Known Member
Haha this is the opposite of what the first post was about!
Maybe somebody has already said this, but passively locating a source of sound underwater is very hard---divers will know!
My hunch is that for a passive system you're gonna have to rely on spectral information (the relative amplitudes of different frequencies in a signal) and have a number of hydrophones to give you directional information (the difference between amplitudes in target frequency bands between hydrophones). I wonder if the boat's hull could attenuate some of the signal to stand a good chance.
There might be more sophisticated ways to do it, but for an experiment you could use two hydrophones on opposite sides of the hull, record some sound from each, and run an FFT on the two recordings. If you have a meaningful difference in amplitude in some frequency band that's related to something like a boat engine *somewhere* then success!
As mentioned previously, stuff like thermoclines, and the shape of the bottom, will affect this.
Maybe somebody has already said this, but passively locating a source of sound underwater is very hard---divers will know!
My hunch is that for a passive system you're gonna have to rely on spectral information (the relative amplitudes of different frequencies in a signal) and have a number of hydrophones to give you directional information (the difference between amplitudes in target frequency bands between hydrophones). I wonder if the boat's hull could attenuate some of the signal to stand a good chance.
There might be more sophisticated ways to do it, but for an experiment you could use two hydrophones on opposite sides of the hull, record some sound from each, and run an FFT on the two recordings. If you have a meaningful difference in amplitude in some frequency band that's related to something like a boat engine *somewhere* then success!
As mentioned previously, stuff like thermoclines, and the shape of the bottom, will affect this.
Last edited:
