Fragmaster just showed me a pic of him chasing another player in multiplayer. The pic was taken using high freq. active, so he was pretty close

Now I was wondering, since it still is an active sonar, shouldnt the victim hear him using the device? How is it working in RL? Since high freq. waves do not travel far, I assume its not a problem for your stealth when using it in minefields and for orientating, but when you use it on an enemy sub thats just a couple of meters in front of you, shouldnt the other subs sonar/active intercept be hearing something?