The secret sound contest is an old staple of radio stations around the world.

The presenter plays an obscure sound, and offers you money as a reward if you phone in and guess the source of that sound.

Often these sound are obscure. Really obscure!

However, the rewards can be high. Some stations offer over $10,000 and the winning amount goes up every day that the sound remains a mystery.

There's also been controversy: for example, in the UK the media regulator Ofcom fined GCap Media, owners of Capital Radio and Classic FM, 1.11 million pounds for operating a secret sound competition ... that no-one could win!

Read our practical and effective ways to help guess the secret sound.

Find out how to play with the sound, read our suggestion on recording the sound that you think is the answer to check if you are right, and learn how to 'crowd source' the solution.

Maybe these will help you win the big prize!

Also, we have collected together a list of secret sound competitions that you can access online.