Sloped baffle

Bombaywalla, sorry for the confusion. I'm referring to a driver's electrical, not mechanical, attributes. Rather than go off on a tangent, if Al catches these last few posts, he might be able to untangle what I'm trying to say. In the meantime, I'll just assume that the only relevant driver attributes that affect phase coherency are the mechanical points Roy discussed in his White Papers.

OP-

Yes. It is important to have a sloped baffle loudspeaker.
Today's drivers are very advanced in design and construction. Therefore, we (listener) want to get the maximum potential out of them during sessions IMO.

Regarding digital signal processing as it relates to these issues, this from the DEQX website:

"In addition to frequency-response errors DEQX’s biggest strength is restoring phase and time-domain coherence by delaying faster-arriving frequencies until slower-arriving frequencies catch up for a coherent Impulse-response. DEQX even corrects timing delays in frequency groups within the drivers themselves rather than just time-aligning one driver to the next."

Thanks for this info Psag. The DSP software definitely considers having phase & time-coherence as an important aspect of its signal processing so as to have cohesive sound. This should tell us something about the importance of time-coherence in speaker design :-)
Looks like DSP might be the way in the future...

Practically, headphones are the best for time and phase coherence. Even good quality cheap ones. Use those as a reference to help decide how good speakers sound in this regard. Then check the measurements if available to see if things correlate.