Improving the sound quality of a room with minimal changes – sorry, but that’s a bit like saying “How can I go swimming without getting wet?”
There appears to be enough irregularity in the room dimensions, as well as furnishings in the room, to adequately diffuse the upper frequencies. But basically, hardwood floors are not good for acoustics, as are hard surfaces in general. And having the rear surrounds mounted forward of the seating, and so low, isn’t doing anything good.
When you say you’re seeking better “clarity,” that give me a clue that perhaps you have bass issues – like, too much of it. If so, it’s likely because of the large front speakers you have. Big speakers in a smallish room can generate excessive levels of bass, even if you have them set for “small” in the receiver’s menu, and that can interfere with the subwoofer’s operation. Actually, there’s no need for large speakers with prodigious bass output and extension if you have a subwoofer. They’re merely duplicating a portion of the subwoofer’s range, so the extra money spent on the larger cabinet and extra bass drivers is money wasted.
And your sub location might be contributing to flabby bass at the expense of extension. Do you have it tuned with a parametric EQ? If not I think you’d be drastically improving performance from your sub by moving it to the left corner and adding a parametric EQ.
Regards,
Wayne A. Pflughaupt