Certainly, if the walls are free to vibrate, then you'll lose some of your energy in making them move. Or worse, if they're not damped, they can make their own sound, making peaks from panel resonance.Most times, the drywall in homes isn't very solid but it's damped pretty well from the insulation behind it. So that helps. In some instances, you'll find a wall or panel without insulation behind it. They're troublesome, because it sounds as hollow as it is.