Some tips for the Ultras:
The sub will be loudest if corner loaded, however (like all multimedia subs) some of its sounds are still directional, so it's usually best situated directly in front or behind you. I've got a corner desk with the sub directly in front of me, which is pretty much the ideal setup for it. (except that my monitor turns funny colors if I turn it up too loud)
The control pod has volume settings for Rear, center and sub. These range from -9 to +15 are all relative to the main volume. For a good starting point, leave the sub and center at 0 and adjust the rear speakers so that they are equal in volume to the front speakers at your listening point.
I haven't used the Klipsch 4.1, so am not sure about them, but the Ultras have no built-in upmixing, so stereo music will play only as 2.1 sound unless you upmix it before passing it through to the speakers.
And, the volume is on a logarithmic scale, but because of our non-linear hearing, every +1 volume increase should be equal to every other +1 volume increase. In short, don't be afraid to turn the speakers up, just take care of your ears.
