Yes, the new signals are the true sound of the missing Malaysian airline flight 370, because nothing else could be making that noise. There are no other missing planes right now, and those signals that we are hearing are consistent with what you would hear from a crashed plane. It has to be the missing plane.
Further evidence of Flight 370's crash site: An acoustic analysis of the two newly found signals shows that they were consistent with a plane’s flight data recorder, and a U.S. Navy Captain also believed they were from an underwater beacon and man-made device. The new signals are consistent with the area of the earlier signals, and since they were weaker signals, that would mean that the battery was losing power.
It is possible that the pings heard are the black box from the missing airliner, but it really does not matter until it is confirmed either way. These locales are very deep in the water and there is a chance the batteries will die before the box can be located.
Considering the vase area of possible locations that flight 370 could have ended up, it is unsafe to automatically assume that because you got a ping, you have found the wreckage. A ping is not what should be considered irrefutable proof. There are too many wounded families waiting on information to make assumptions. Find the box associated with that ping, then make your conclusions.