I'm finally adding a subwoofer setup to my frankensteinish setup. The Dayton 10 inch is scheduled to be delivered today. I have an onkyo 502 receiver, currently hooked up to a pair of Infinity RS-9s and several Polk RM6005 satellites in a 6.1 configuration. I am hoping to add a bit of edgy bass to round out the sound, but boominess does not appeal to me, and nor do I think it would appeal to my neighbors (I live in a condominium.) I'm looking My living room is carpeted, although there is an area in front of the mantle that's marble. I'd like to limit my placement experimentation to a minimum, as I'm guessing the thing is fairly heavy. I have several questions. 1. There seems to be a dispute over how best to connect the thing. I'd like some LFE-- I do listen to DVDs and most of my TV channels are dolby digital 5.1. So, I'm thinking subwoofer out to RCA in. There are two RCA inputs, however, and only one sub pre-out. Some have suggested using a Y cable to connect both outputs, noting that this will "boost the signal by 3db". But won't the Y attenuate the signal by 3db? So very confusing... 2. I calibrate my speakers using a Radio shack sound level meter (the analog one) and receiver generated test tones. I understand that a correction must be applied, and there are various tables that show this, But presumably, an accurate correction depends on the frequency of the test tone. Anyone know what frequency Onkyo uses? I do have a few THX-optimode disks which might be useful in a pinch, but I don't have ready access to a specialized disk. (and I've heard that various brands are, in fact, deficient in the very tests I describe). I have ready access to Tower, if push comes to shove, though.