Help me find this opera song!?

There's this opera song I have been trying to find for a long time now. Since I don't know anything about opera it's very hard to find all I know about the song is that is sung by a female and in a part of the song it sound like she's just saying a bunch of ah's put together ( ah ah ah ah ahhhhh), and when she sings it she kind of sounds like someone pressing a on, so she would ah pause like .1 sec then say again over and over doing a crescendo on the way. I don't know if what I know will help find this song but thanks for the help!