Subwoofer for classical music listener

You might not have it  dialed in quite right. Some of the imaging problems come from the single sub. you have both channels mixed together which cancels the ambient and phase signals coming from the low frequencies for both Left and Right channels. Contrary to popular belief, there are signals down in the low frequencies that will give clue to direction and space.

"Upon extensive listening, I've discovered that, although I love the sub, there is a definite coloration and lack of precise imaging when listening with it on."

rvpiano-

Assuming you've done your homework on sub location, you're still not done finding the sweet spot for the sub.

How about BEHIND the listening position? Every room is different so there isn't a absolute "right" location. In my case, the subs(even one) are invisible sonically, with just a  hint of low frequency "presence" in the room, noticed when subs are tuned off.

Also, IMO there just isn't a "set and forget" gain setting, since bass levels on some recordings(rock) are ridiculously high or low and gain must be adjusted.

With Classical music, I find myself not having to fuss, once I find an acceptable 
setting.

The real solution is a remote for the sub, and the listener adjusts to taste, just like the  volume remote. The upper level REL  G1's have this feature, way out of my reach$$

Finding that spot where the sub "locks in" is a pain, and the ideal spot may not be feasible, but you can find a compromise.

Good luck

Tablejockey:  I'm sure you're right that I haven't found the ideal setting and spot for the sub.
I have limitations as to where I can place it (furniture, closets, doorways and most important, wife.) I also don't know if I have the fortitude for the job!
Right now I'm listening to an audiophile pressing of "Tony Bennett at Carnegie Hall." Without the sub it has no character at all.  It comes to life amazingly with the sub.
Wonderful!!
But with most classical, the way it's configured now, I just don't get the same enjoyment.
Not that I haven't tried.  I've spent several days and hours at it.  Maybe I should be more dedicated.

I say move it around to as many acceptable places in your room. Sometimes the most unusual spot makes the most difference.
Bob