The focals will be more apt to reveal this particular issue then perhaps other speakers. Trying warmer cabling as suggested is a good idea as is looking at your AC delivery, (think Oyaide GX or R1's in your case). Also room treatment at all first reflection points, back wall, ceiling etc
But because of your smallish room and perhaps you are more sensitive at particular freqs. You may end up looking at a speaker that is a little kinder in the treble.