Moving and finding the best place for subwoofer can be cumbersome and time consuming task say the least. But this method is an easy alternative, and might achieve better results. One have to get on hand and knees to for this method, and keep the head low like I did.
The first step would be to place subwoofer at the sweet spot where most listening is done and wire it up. For best results, the Sub have to be raised off the floor to be same height as ear level (where listener head would be).
Turn off the main (and surround) speakers, but leave the LFE channel and Sub on. Play a CD that have a constant low frequency rhythm and adjust the sub so the low frequency is distinct and hearable. Now get on hand and knees and keep the head low so it is at same level as the subwoofer would be when it is siting in the floor.
Now stick your head to where most probable locations for sub would be in the room, and listen for low frequency notes. In my experience in doing this experiment, I found out that some locations in the room, the bass notes had a ring to it, and some locations the bass was overwhelming. So these locations where obviously not ideal for subwoofer placement.
But in one (or two) location in the room, the bass seem to be much more smoother, distinct and not overpowering. The bass notes where clearly audible without boomingness. So I place the subwoofer in that location, and waaalla, success!! The subwoofer sounded much better than where it was located before and blended nicely with main speakers.
Offcourse after finding the best location for the Subwoofer, the gain and cross over have be djusted again for best sonic quality, but one will find that this method is very easy and awfully effective.