I tried keeping the subwoofer pointed towards the avr stand as per ur suggestions.There was no improvements and the loudness in the bass reduced slightly. But to my surprise the speakers performance improved buy a lot. I changed the phase switch and the sub performance was slightly better in this position but the loudness in bass still being slightly reduced.
If loudness is reduced....manually increase the level on the sub.....to compensate for difference and try again.....have you tried changing LPF for LFE?