How about these acoustic panels?
ACOUSTIC PANEL WALL MOUNT SYSTEM
Think they would work about the same
The acoustic panels are from this company:
ATS Acoustic Panels
The only problem is they are only 4 feet high, do you think that's high enough for drums? And then could I just raise them for vocals? Or would that not be effective because of the seepage above and below them?
It wouldn't be too hard to make kind of a stand for them. And they're cheap...