Recording with bass to align my subs with my speakers

Right. And nice tip to help find xo level. Thanks.

Woots, most of what I said is passed down from Duke, who makes the Swarm subwoofer system. Combined with a little of my own experience. But even a lot of that I owe to him. Probably would never have tried a DBA without reading about it here from guys like Duke.

Study Fletcher-Munson Equal Loudness Contours. Notice perceived loudness is very uneven, exaggerated and compressed at very low frequencies. In other words, very low bass below a certain threshold is very hard to hear at all. But then once it is, very small changes in volume seem larger than they are. 

Because of this, the best way to set sub level is by listening to a lot of different records at various volumes over a long period of time. Every once in a while when you think it will help make a very small change in level. After a while, week or three of infrequent tiny little tweaks, you will settle in on a good compromise.

Or you can play your reference tracks, jack them around to where they sound impressive, and wonder why only the reference sounds good and only at that one reference level.

Your call. Choose wisely.