I have a bit of classical music running through my head. How on earth do I find out what it is?

[SilentBoob]

All I can tell you is that it is very calming and watery. I heard it done on a violin this morning, but am sure have heard a woman singing it.

There's a phrase in it that goes like a waterfall from high to low, sometimes on 4 notes and sometimes on 7. I think.

Umm...

Was it on the radio?
if so you might be able to find it online on the station playlist?

Download the shazam or soundhound app on iphone and sing it to the phone. I do this all the time.

No, it was someone's ringtone!

Will investigate shazam & soundhound.

At a guess, is this it?

No it wasn't that. It goes

Ahh ahh ahh ahh ooooooooh from high to low, but not straight down the scale.