[mpyne]

About right, but more importantly it's highly dependent on factors like pressure, temperature and salinity, all of which change in relevant ways in the ocean depths.

People imagine sonar like it's radar, where you get clean bearings and distance readings, but it's so much noisier and hard to decipher.

And yet it really does travel long distances which is both good and bad if you're a submariner.

[euroderf]

And this has implications for hearing damage to cetaceans, yes ?

[mpyne]

Salinity, temperature and pressure aren't normally large factors for cetaceans, no.

If you're referring to active sonar, that's an issue for anything with ears under the water. But animals themselves also can make loud noises (e.g. the sperm whale can reach 230+ dB), as can surface ships with their own active sonar kits.