I have a new sub on order that has down-firing ports. It comes with 1" inch rubber feet on the bottom, but I have medium thick carpet (freise) and an 8 lb pad. Since the subwoofer will sink in the carpet a bit, I am concerned that the ports will not have the much clearance underneath. The Auralex isolation risers are not an option for me as this sub is as high as I can go in the space I am putting it in.
How much clearance is really needed for the ports? Will I be OK?

Thanks

anyone? :)

1 inch is bare minimum. Without knowing what the owners manual states for clearance I'd go get some carpet protectors and raise the sub up to a least 1 1/2 inches.