"OodlesoFun" wrote in message

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).

The general rule is set the crossover as low as you can without overloading
the satellites with bass. That will depend on your room and the loudness you
prefer to listen at, among other things.

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?

Yes, or maybe you could set the volume control on the woofer a little lower
which might reduce any possible noise pickup.

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?

The tube is called a "port" and should not be blocked. If the port is
pointed at the wall, that side of the woofer should be several port
diameters from the wall. If you can't do that, point the port in some other
direction, but preferably not at the listener.