I don’t watch a lot of boxing, but seeing it occasionally I’ve noticed that in each round the boxers get an audible warning when 10 seconds are left - it sounds like somebody pounding on the mat.
Is this new or has it always been around? I don’t recall it in the long-ago past, but given the advances in TV coverage maybe it was always there and I just couldn’t detect it.
Started in 80s that I recall. It’s usually someone pounding on the mat, but in some places they have distinct electronic ringer, different from the bell, and others they clack a couple of pieces of wood together. The idea is to give the fighters and the ref a warning that the round is ending to avoid fighting continuing after the bell. Often the result is boxers winging a bunch of punches to try to steal the round. Often that’s something they start at about the 2:30 mark which resulted in another rule that the corners can’t signal the time to their fighters. Even after audible signals were cracked down on they started using tactics like having a cornerman turn his hat around backwards at particular time.
All in all this has done little or nothing to improve boxing. Just a couple of weeks ago I saw a fight where the length of rounds and the time between rounds was mistimed, accurate times would make a bigger difference. In one case it led to a heavyweight championship being won by Greg Page with a knockout over Gerrie Coetzee at about 4 minutes into the 8th round.
It’s usually the wooden clapper that I notice and they’ve been doing it for as long as I can remember. As like most boxing rules, it was probably implemented at various times by the various organizations. Even most MMA fights us a 10 second warning now.