Getting Avia would help as well. It has a wonderful regiment of test tones for speaker/sub setup, calibration, and evaluation. It also has test patterns for tweaking your video display.
Once you get through all of the setup and have that done properly, any poor sound issues are going to be due to the room and/or your personal tastes versus the sound of the speakers. Ie., if the speakers are close to walls or glass, etc., you will have a lot of sound reflecting and blurring the sound. How are they positioned? Are the (front) speakers on an arc, equidistant to the LP (all 3?), equilateral triangle between left/right and LP?
Toe the speakers in more and/or move them further from the walls -- although the best thing is to treat trouble spots with
acoustic panels, which are pretty affordable considering the huge improvement in sound quality they will give you. If the floor isn't carpet, but bare tile, wood, etc., you need to have rugs and other coverings to help dampen reflections. For muddy bass, after setup issues, placement and room interaction is usually at fault. If the mains are running Large/full-range, set them to small and let the sub handle all the bass. The sub can be moved around for optimal sound (flattest response, which can be tested with frequency sweeps on Avia, etc.), and this lets you keep the speakers in the spot for optimal sound, soundstage and imaging.
Your room is your biggest speaker, because it greatly affects what the sound sounds like by the time it reaches your ear - sound bounces around all the walls and combines/cancels out and reaches your ears at different times. I have a window at the first reflection point on the right side, and opening it changes the sound because sound goes outside rather than being bounced back off the glass. That's where I will be putting an acoustic panel (about $60 each) pretty shortly here.