non-linear shaped room bass problems

[Synthsayer]

I have had a lot of trouble getting the sub-bass to sound right in my listening position. I have an O-Audio 500W amp that has nice tuning features. I am also using Harmon-Kardon AVR 146 with DIY front speakers w HiVi Research 8" and Morel MD20T dome tweeter. On the right side the nearest wall is 7'. On Left side there is an open space leading into another room. When I stand 3 feet away and centered between from the front speakers it sounds great. But, when I move back to my recliner, I don't hear as much punch.
I have moved the subwoofer many times and tuning it is not really the problem. I seem to be losing the mid-bass. I am considering rearanging the entire system.
I am trying to figure out how to uplaod a Visio drawing so forum members can see the layout of the room.
Maybe I have posted this in the wrong area. If so forgive me. I will move it. Have to get back to work now.
Peace

[BoomieMCT]

What frequency are you crossing at?

What is the shape of your room, where is your sub and where is your recliner?

This sounds like a crossover issue or a room mode issue.

[Synthsayer]

Crossover is set at 80Hz. The room is 'sort-of' L-shaped. Sub is next to TV stand along one wall and recliner is along opposite wall. If the room were an upside-down L, the entrance of my apt. would be at the bottom of the long vertical line and listening area the short horizontal line. Does make any sense?
I made an MS Visio drawing but have to figure out some way to upload it or link to URL.
I moved the front speakers away from the wall some, changed sub amp's parametric EQ setting to High Q around 40Hz and -8db. It was set to lowest Q at 70Hz -6db. The new setting brought back the punch and smoothness. I don't have a spectrum analyzer right now and am going by ear alone. Also, since I mostly watch TV programming and the mix on each channel differs, that makes things even tougher to judge.
I can listen to 'Dark Side of the Moon' and get the system set where I think it is great. Then, when I change back to TV sound, one channel sounds boomy and another sounds thin. It would be nice if there were more consistency.
I used the room modes calculator found at http://www.marktaw.com/recording/Aco...WaveCalcu.html
I agree with you about room mode problem.
THANKS

Peace:-)