Then you need better speakers //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif Don't bump the xover point on the sub to make up for a deficiency in your stereo somewhere else. You need better midbass speakers.
If you bump the xover point on the sub up too high, not only will the subs sound like crap (they aren't designed to excel in that high of frequencies) but you'll likely pull the soundstage behind as well as loose some subbass impact.