One point not mentioned here is that when you set the distance from your sub to your listening position, add no more than 10 feet! I know it sounds strange but you do mention that the sub kicks in too early and it may be because you have it set too far away which is not good. I discovered this important point through years of research on various forums. So give it a try. If you set the sub distance too close, it may fire too late, too far away and it will fire too early, 10 feet over what it actually is seems to work great.
YMMV
