I am just wondering what settings the crossover should be on on the back of the sub there is 2 control knobs one is a low pass frequency there is a phase switch do these make a huge difference if not set right thanks.

I'm new, and not a pro to say the least, but I can just pass on some of the advice that I have recieved from others on this site.

Phase switch: If it's a toggle switch that lets you do either 0 or 180, I'd just try each one from your sitting position and see which sounds louder. If it is a continuous knob, you can either hoof it back and forth, or have someone at the sub to adjust the knob from 0 (most common setting for a front placed sub) in increments of 20 degrees until you find a peak sound level. It just helps your sub speaker be "in phase" (in sync) with your front speakers.

If you have a good reciever, just set the crossover freq knob on the sub all the way to the right ( 120hz or Bypass), and set your cut offs on the reciever. Depending on the size and freq range of your front speakers this could change your setting needs some.

I have floor standing speakers up front, and have them set to full range, and have my sub freq cut off at 80 hz, as my fronts are rated to go well below that (39hz and from advice on this forum, I had the option of setting the front crossover freq at 2 x the low end extension of the mains, or keep them set to full range)

If you have smaller bookshelf speakers, then I'd keep them set to "small", or use the 2 x lowest freq trick, then set the sub to start where the mains leave off. Again, all in the reciever settings. If your reciever doesn't have these settings, you can try to use the dial to dial in these settings on the back of the sub.

I chose full range on the fronts, but I have my sub set @ 80hz to start helping them out in that range. I like listening to 2ch audio at times, and I like the way full range fronts sound while doing that.

In the end, set it to what you think sounds best. I searched all over this place and found tons of threads about how to set crossover frequencies (opinions all over the place). After all the advice is given, in the end you should do whatever sounds the best in your space and speakers. I'm not sure of the freq extension of the your main speakers, or of PDR 8, I used to have a PDR12 that did a fair job of extension.

P.S. for the more advanced posters of this forum... Pleae don't rip me to shreds, I'm just a newbie trying to help a newbie, some of the advice on this forum can get pretty indepth, this is just what I gathered. If I'm dead wrong, I take criticism well ;-)