I am still running a pair of Cain&Cain Abby's that use a Fostex single driver and a Voigt pipe design. They have kept pace with my other upgrades, and I love them.
Although their bass is surprisingly good, there's nothing to stop one from adding subwoofers; I also recently added rear-firing horns with exactly the aim that Ralph described in his post: "The solution is [... to] add a rear firing tweeter (and not cross over the main driver) to correct the tonality and help with soundstage palpability" (both products I purchased from Audiokinesis).
These two additions solve many of the issues with extension while preserving the coherence and liveness of single main driver. I am sure many members here have superior set-ups, but OP, you'd be surprised how full and immersive these speakers can sound.
Bache audio and Tri-Art both pursue designs built around a full-range driver supplemented by super tweeters and woofers.
Although their bass is surprisingly good, there's nothing to stop one from adding subwoofers; I also recently added rear-firing horns with exactly the aim that Ralph described in his post: "The solution is [... to] add a rear firing tweeter (and not cross over the main driver) to correct the tonality and help with soundstage palpability" (both products I purchased from Audiokinesis).
These two additions solve many of the issues with extension while preserving the coherence and liveness of single main driver. I am sure many members here have superior set-ups, but OP, you'd be surprised how full and immersive these speakers can sound.
Bache audio and Tri-Art both pursue designs built around a full-range driver supplemented by super tweeters and woofers.