Holding down one note in the background.. What is this technique called? (Example)

Support & Feedback Subscriber Support
1

This technique is in loads of songs, but Heres an ex. of 1 song doing it, its 17 seconds inbr
br
http://www.youtube.com/watch?v=PVn7CVvIKW8br
br
Whats this technique called, and whats the proper preset to be using for this

2

Maybe the Pitch modulation.