@mulveling - I am genuinely curious about your post concerning phase errors in multi-driver speakers. I was reading Floyd Toole's book on Sound reproduction and he makes a point in that book that phase errors in normal full range systems are not usually bad enough that it has a noticeable impact on the sound quality.
I am not good to explain this, as in the end it really boils down to "I like what I hear with Tannoys". Phase coherence (at the crossover) is only a theory or possibility for why some of us particularly gravitate to Tannoy DC sound - Tannoys are NOT time aligned, and only phase coherent at the crossover point, but this may be enough? Its symmetric, controlled dispersion is another possibility - this can reduce the impact of a room's acoustics on resulting sound. I also like a "mid-field" arrangement with my Tannoys, which reduces the room's impact even further. With large multi-driver speakers you cannot get so close or the image "pulls apart"! Tannoy's image is clean and lifelike at almost any distance. The supertweeters can sacrifice a little bit of this coherence, but that's another topic and set of pros/cons.
The key result is that when I listen to something "busy" like hard rock or metal, it has to maintain the musicalilty and a natural "flow", without feeling like it's falling apart or the musical elements are fighting each other. When I do like other companies' speakers, they tend to be simpler, smaller arrangements like a 2-way with the tweeter and smaller woofer close together. An example would be than Magico S1 and Acora SRC-1. These have great, liquid musical "flow" and I really enjoyed listening to them. Sure, I'd love if they had better bass extension and impact, but when you go to larger models - I hated the A3 and did not really enjoy the larger Acoras (including the $200K one) that much. That A3 in particular sounded like it had a Home Theater sub in it (thumpy, out of time, easy to localize), and I hate that - this always punches me out of being able to enjoy music. Yes, room interactions can cause this but I've never heard anything at all like this from a good Tannoy model (to be sure, some are better than others). I did like the S5 (heard it back when it was an Mk 1), but still the S1 may have been more musical.
phase errors in normal full range systems are not usually bad enough that it has a noticeable impact on the sound quality.
"Usually" leaves a lot of gray area, and we are all individuals to "some" extent :)