>Wouldn't it be easier to use quieter balls rather than carpeting the channels?
Sure, I guess. Tennis balls would definitely fit...
BUT, I was trying to build a *fantasy* game table, and while tennis balls would be quieter, it would lack some of the fantasy feel that I was going for. However, the next owner of the table may have a different view, so that would be fine too. YMMV is always the rule.
It could also be a bit of a pain to open and close the tennis balls. The orbs I use are hinged, with really nice clasps, and worked out quite well.
So, whatever works for you. For me, the sound was never an issue. I prepared notes ahead of time (a couple per each player along with a bunch of generic ones) and I'd send them all to each player at the same time. Then, it was actually helpful to have the sound so you knew that it was on it's way.
Would the carpet damper the speakers?
Nope, not at all. The speakers face outwards, at the knees of each player. The sub woofer just sits in the main cavity of the table and just emits sounds, mostly via the players "send" ports. The player "recieve" ports (and the GM returns) are basically separate.
Sorry about the long-winded reply. I just had a glass of wine.
