Hi All: First time poster (to any forum believe it or not). Anyways, I am the proud new owner of a pair of EP600s. These are my first ever subs as I've always stuck with a 2 channel stereo system. I bought them with the intention of building a good home theatre system which I'm working on now but the room won't be ready for probably another year. In the meantime (just got them yesterday), I'm using them with a pair of Polk bookshelves (RTia3) and a Yamaha stereo receiver. I have each hooked up (via high level inputs) to one channel and placed near each respective Polk speaker as a stereo setup. I streamed spotify through the stereo but I really can't hear the axioms. It's either because they just integrate so well in the lower hz that they're just barely shading that bottom end, or I've done something wrong, but when I turn them off and just listen to the polks I don't really hear a difference (even if I turn the sub volume way up). Maybe most music doesn't have low enough frequencies for the sub to do much? And when I find some bass-heavy tracks just to try to test the subs, I can't turn the system up too much as the polks start to strain. Is there such a thing as an external crossover unit that I could buy to let the Polks handle only the highs and mids? When I hook up each sub to the receiver via high level inputs, do I only hook up to one channel considering I have two subs, or would that even make a difference? Apologies in advance for these beginner questions, but I am just really so excited to feel what these guys can do but so far I'm not really hearing anything. I would think that even with low overall volume, as long as one cranks up the subwoofer volume one should be able to hear/feel the subs. thanks in advance,