that transition from hard to smooth was a move he used a lot.

And you already been mentioned, this bassline is straight-up Raydio too.

Here's a video of him talking about it a little: http://www.youtube.com/watch?v=SPF6Ffv7FpI&t=2m49s

I'm trynna post the UnSung clip but I can't seem to get the direct link. But if you click here http://tvone.tv/unsung-videos#

and underneath, select the video "Ray's Hard Lesson," you'll see it.