Strange tune

[Alliz5compact]

Since the 7.1.1 update  my phone has been playing what I thought a notification sound. All notifications are blocked,  this happens about 3/4 times a day, please help. 

[Qatrium]

@Alliz5compact

Do you have your phone inside a wallet case, and there are transportation or credit cards in the same wallet? If yes, this can be the sound of NFC read error. Remove the cards or disable NFC to make it go away.

[Alliz5compact]

Hi thanks for the info but it's not in a wallet,  it happened this morning after I turned it on, not even near any cards.

[Qatrium]

@Alliz5compact

Does this sound like your default notification sound or it's different?

[Alliz5compact]

I've never heard it b4 

[Alliz5compact]

Hi I have found the tune. It's in phone ringtones. Xperia xperia,  I have not set this as any notification,  all my notifications are turned off.