Will a sub woofer mess up my tone and phase aligned speakers

I used to have 1Cs, and I added a pair of 2Wq subs. They did not mess up the phase or tone, but the in-line filter was less than fully transparent. I later upgraded to the battery biased Vandersteen crossovers, and the transparency was restored. The Vandy 2Wq is specifically desigend not to introduce phase issues with the main speakers.

Agree that Vandy 2wq sub is the way to go.  Once you have the sub dialed in you won't want to listen without it anymore.  It's a game changer. 

I've never heard a well integrated sub that didn't use EQ. I've heard subs sound decent to good, but not perfect.

Fortunately this is something that can be done later.

Best,

E

I ran Vandersteen subs for years. The Vandersteen sub system with the crossover before the amplifier does integrate very well. The problem is the crossover is not transparent. As I upgraded my system I moved to the battery biased m5-hp crossover which is more transparent than the stock cossover but still smears precise sounds like higher frequency plucked strings and well recorded vocals. For a while I ran the subs with rock and roll and would remove them for jazz. I finally got tired of this and moved the Vandersteen subs into the home theater system

The Grotto has a three position phase switch and along with a pair of long interconnects would allow for an optimal placement which should be enough to obtain a good deal of sonic satisfaction. 

If your dissatisfied with its performance and decide on a more sophisticated DSP subwoofer keep the Grotto because you may be able to slave the equalized line level signal from the DSP sub. Together they may better load the room and decrease room nodes.