Yup somehow after Audyssey calibration of the receiver, I still find the bass of the sub a bit thin. I surmise the receiver assigned my fronts to large i.e. the fronts will also be contributing to the overall bass output thus the receiver's lowering of the subwoofer's level. I might be wrong on this though just correct me guys.
As advised by Sir Mark to change my fronts to small and leave all the low frequency load to the sub I had to crank up its level a bit to achieve the output that I am satisfied with. Actually it's all a matter of preference just don't drive the sub to distortion levels.
after doing multeq, i usally get xover of between 30 to 50hz for the fronts, center and surrounds. If I remeber it correctly, if the resulting xover after calibration is 60hz or above, recommendation is to maintain it at that. THX recommended to is 80hz so i manually adjust the xover to 80hz. As for the LPF of the LFE, THX recommended is at 120hz. I usally get that setting after calibration. On the subwoofer itself, i set the xover frequency to the highest level.
Prior to doing calibration, i follow the recommended setting for the subwoofer gain of midlevel. If i get a negative level calibration result on the high side( the highest for me is at -12 db), i decrease the gain setting a bit). When set to midlevel, i usually get a -10db result so i set my subwoofer gain to 10 o'clock postion and re run the calibration again. This setting gives me around - 6db 0r -5db. I then increase this level to 6 steps in the reciever and this has by far given me the best result overall.
i hope i have narrated everything correctly