I thing the cupped hand is older. I learned it as a child and still do it, and the real trick is when I have to switch back to the pipes or whistle and have to drop the hand at the last messure to grab the pipes, and the change in tone hits me. It takes practice to not be thrown by that, but one can be much more carefully on pitch especially if one is singing with harmonies... or you are doing the harmony. Cheers, Larry