I can't explain in any technical detail but the 6/bypass was a vast improvement for my ears. I dont mess with the sub phase (no adjustment) it is a noticable difference but not a bad one. The phase shift seems to smooth out the bass a little, and add a little too. I can locate the sub a little more in this setup. It is worth pointing out that when A/B'ing this you will get a little more volume with the 6/bypass. This will make it seem better than it really is at first, but after you live with this config for a while you start to really notice a better stage (at least I did). Good luck!