I've been to a couple of Linkin Park concerts and both times there was a noticeable funnel or two attached to Rob's drums. I've always wondered what audio enhancement it provides. Does anyone know? I've attached a couple of pictures just to illustrate what I'm talking about.
A duct will modify the cavity resonance of a drum, so that may be why he's using it. Even if it's not attached to the drum, the duct by itself will create a standing wave resonator. Both or either kinds of resonances can be used, and he may like the interesting sound it creates. Or he could be doin' it just to make us wonder about it.
Thanks a bunch Wayne for letting me know what the deal was with that funnel. It's been driving me crazy since I first saw it! My buddy who was with me thought the funnel blew air up to Rob to cool him down. I knew that wasn't it.