i think it's from 70's / 80's roundabout , male group.
It is a bigger song, even a hit, but definite oldies song which radios still play today
Not 100% but it could be the start of the song , tonight TONIGHT
It may even go like this: tonight , TONIGHT(louder/more powerfull) ,tonight, TONIGHT(louder/more powerfull), toniiiight
Try to get a slight hint out this :
http://www.zshare.net/audio/948183141e63b436/
m mmm m mmm m mmm m mmm
P.S if you think you have some sort of idea but dont recognise the TONIGHT "thing" there is small possibility that its another word that iv'e missheard.