Hey OP!! I can definitely help you out with this one!!!! If you have no line in (rca) or lfe in on the back of your klipsch subwoofer. Your going to have to set it up via speaker inputs. On the back of your sub you should see 4 sets of speaker terminals. Man I wish I post pics.. I could show you on the back of a psw 505 I have laying around. Anyway should be 4 black, 4 red. 2 should say something like "speaker in", the other should say speaker out. What you want to do is run the front left and right speakers from your 818 straight to the input on the subwoofer. Then, run two more speaker wires from the sub woofer to each of your front left and right speakers.
Now, the next thing you need to do is let the reciever know what you've done. Go into the onkyo 818 menu. Under speaker settings. Set subwoofer to OFF. FRONT to Full range, center and surrounds from 80 - 120hz depending on their size. On the back of the subwoofer...I'd set it's crossover about its halfway point... don't know it's quality...but the higher quality it is you would ideally want it to play the full range of lfe which would be to 120hz.. The lower quality it is you may find it sound better with a lower crossover setting of 80-90hz. Volume on sub 10-12 o'clock..
Once you test everything out and get it close... go ahead and start your audessey XT32. You'll probably have to go back into speaker settings and adjust your crossover setting after auddessey. Other than that, you should be all set!!!
Sorry for the delay, moving into the house and unpacking.....So the sub is powered and has 2 red and 2 black on the back. one set is line in and the other is line out. So it sounds as though Mechsmoto's guidance will work, however it is only 1 line in and 1 line out....so not sure how the system will differenciate between left and right if I hook up the FRONT L & R thru the sub. Can I bridge the sub using the red from FRONT R and the black from FRONT L or vice versa?
Use one line out RCA from the Onkyo sub out and connect it to the line in on the sub. It only needs one and the Sub Outs on the Onkyo are the same - there is a Y on the inside of the case that makes the two sub outs that you see on the back.
Dougc... I believe the op stated he has no rca or lfe connections on the klipsch sub... which is why I suggested using the speaker level inputs the sub would have had to have. My PSA xv15's don not have speaker level inputs.... but my older psw 505's do. This is why I tried to help the op.
He threw a "curve ball" at me so to speak by stating there are only 2 speaker level attachments.(which i would think would have to be one set "in" and ine set "out". I would think running only one tower through the sub would have to sound uneven... unless of course he has two of the klipsch subs????
Need a bit more info OP?!?! How about a pic of the back of klipsch?!?!?
When I get home I'll show you what I mean by uploading a pic of the back of my psw 505..
I figured the pic thing out!!!!!---- send it to email first, on android phones--- this will give you the option to change the fill size. Choose medium or small.... download the email pics(file size modded) back into your phones gallery, log into home theater shack... use advance reply.... upload your pics!!!!!! (Will show up in your gallery under downloads!!)
Just the model of the Klipsch sub is good enough we can look up what it has for ins and outs. I can't think of any sub that would have high level inputs and outputs that would not have a line level input as well.