I have a harmon/kardon satellite speaker system and have some questions
regarding the subwoofer (powered, downfiring, only hookup option is from
single RCA jack).

First off, these are small satellites, so what should I make the crossover
setting on the receiver? (100, 150, and 200 are the options) (the subwoofer
itself has no such option, but I think it reads "60" somewhere on the back).

Also, the woofer has a volume(?) control knob on the back. But I can also
control the subwoofer through the receiver. Is one set of controls better
than the other? Could I just set the woofer's knob to half and adjust the
bass via my receiver remote?

And finally, the woofer has a hollow tube on the back panel. I have the
subwoofer practically against the wall (not the best place, I know, but I'm
cramped for space). Should I just turn the subwoofer around and allow that
tube to face the front rather than against the wall?

Thanks, and sorry for the long post.