Played for the first time in a new documentary, the sound has a regular, steady beat which caught the attention of experts - and sparked hopes that they could be SOS signals from those on board.
The audio of the 'banging' sound, initially providing hope for those trapped inside the doomed Titan submersible bound to the wreck of the Titanic, is revealed
Titan sub disaster: Audio of banging that gave families hope to be released birminghammail.co.uk - get the latest breaking news, showbiz & celebrity photos, sport news & rumours, viral videos and top stories from birminghammail.co.uk Daily Mail and Mail on Sunday newspapers.