My assumption is that hearing this kind of long distance noise is well within the laws of physics and what we know of the U.S.'s capability. So I don't see this as "additional capability", but rather, am asking from a mindset of "How did they
not hear a suspicious sound at the time of the missing sub?"
Whether they did or not, nothing would presumably change about the Coast Guard conducting search-and-rescue/recovery operations (since they still don't know for sure what happened). Worth pointing out that private explorers, led by Richard Garriott (aka Lord British, apparently), complained that they had optimal rescue equipment but got pushback from the U.S. officials:
https://archive.is/HXtFn
> “Magellan has received mixed signals, first hearing from US Gov to get ready, waiting for plans, then getting told to stand down,” Garriott wrote in an email sent to Vice Admiral William Galanis, commander of Naval Sea Systems Command, U.S. Coast Guard Rear Admiral John W. Mauger, who is leading the recovery mission, Congressman Lloyd Doggett, and Representative Eric Swalwell on Wednesday afternoon.
Again, hard to know if this is just standard operating procedure or not. If it's the case the U.S. govt already had things figured out by now, then it makes sense they weren't going to expedite Garriot's group, given that the search effort had already resulted in the loss of 1 (maybe 2) search vehicles:
> In addition, at least one ROV, possibly two, was damaged or destroyed during the search-and-rescue mission—a testament to the difficult conditions currently facing rescuers.