What is the longest a echo or vibration has ever been recorded

Does a monotonous drone count? That's what one of my X's was like with her non-stop talking. LOL

Probably the long "ringing" of the earth from a major volcanic explosion - I believe I have seen reports that the sound blast from Krakatoa circled the earth several times and the seismic waves were detected on more than one passage around the earth.

The microwave echo of the Big Bang...

It took 13.7 billion years...