OK so basically JBL is not in the time alignment camp like most other manufacturers. You just admitted it in your explanation.
Like I said in my original post. As long as the design meets the B+L graph I originally posted. That means below the curve not at 2.5 Msec at 750Hz where it becomes audible.
Like the 3 systems graphed that are below the threshold.
Those are Stereophile step response graphs buy the way.
Why don't you just admit the 1400 is not time aligned/coincident as in the review? What's the big deal?
Text from the Array Review
"In the time domain, the 1400 Array's step response on the tweeter axis (fig.8) indicates that all three drive-units are connected with positive acoustic polarity, and that the tweeter output arrives at the microphone half a millisecond before that of the midrange, which in turn arrives half a millisecond before that of the woofer.
This is definitely not a time-coincident design, though the fact that the ear/brain does integrate arrivals over a longer period than 1ms should mean that this won't matter much.
LG was impressed by the stability and accuracy of the JBLs' imaging, which you'd think might be adversely affected by the lack of time coincidence.
But as far as the lower-frequency units are concerned, the 1400 Array's step response is at least time-coherent, in that the overshoot of the midrange unit's step smoothly leads into the woofer's step.
This suggests an optimal crossover implementation."
The Key is optimal crossover implementation which again I said in my post. Smooth driver integration and good polar response being the main focus.
Essentially all well designed systems are time-coherent. There is a difference they are not the same.
Rob