Based on its positive reviews, I'm hoping to buy a REL Quake subwoofer. Most subwoofers are front-firing, but Quake is downfiring, ie the bass-bin aims towards the floor. Before I consider buying it, I'm wondering if there's any difference in sound quality between front or downwards firing sub-bass? With the downfiring Quake, I wondered if the floor gives some unnecessary and uncontrolled reflection or absorbtion that interferes with the sound quality? Does a carpetted floor (like in the TV room where I'll be using it) absorb some of the bass, which won't be a good thing? Or would a front-firing subwoofer be better, with no wall or floor in the way? Thanks.