Fourth clue revealed for Nick's Secret Sound with £340 up for grabs

A fourth clue has been revealed for Nick’s Secret Sound as the prize pot reaches £340 for the correct guess.
If you haven’t been following the game, Nick Hancock plays an obscure sound on the radio every morning at 8:10am.
Listeners can then call in to have their guess – and if they can guess correctly, will scoop a cash prize which currently stands at £340.
It’s all thanks to sponsors Helijet Aviation.
So what are the clues?
Clue 1: Gets nearly all of us going
Clue 2: It’s on nearly all of the time
Clue 3: Some people watch but some people take part
Clue 4: Before you can play, this must be the way
Does that help with your guess? Take a listen to the sound here:
Think you know the answer? Enter here for your chance to play!