I used subwoofers for many years but could never completely eradicate occasional room node or crossover aberrations. As also noted by wolf_garcia, different recordings also contain quite wide variances in bass levels which can be extremely annoying. I do not want to constantly adjust settings on the subs to be able to enjoy music.
Several years ago when I heard a friends system using a DEQX processor & two subs I could not believe, firstly the clarity of the overall music, but mostly the absolute slam and transparency of the bass and no sense of room nodes or crossover point. I had heard nothing like it before.
I added DEQX to my setup early 2012 and, likewise I now have no issues whatsoever with twin sub bass integration. I have also created four configurations, selectable by remote, with 2-3 my ’normal’ listening setup and 1 for bass light music, 4 for bass heavy. In that way I can choose the appropriate setting and whatever type of music is played, bass is as near perfect as I could ever want.