Does Time alignment and Phase coherency make for a better loudspeaker?

Using DSP  a linear phase perfect impulse response can be done and is in certain active speakers. 

What's the deal with the usage of " time and phase" ? Aren't they the same thing or I'm thinking of the wrong thing being discussed. Anyway with the Dutch and Dutch 8c there is a linear phase mode and a reduced latency mode which turns off the former. Outside of a heavily treated monitoring room or anechoic chamber you won't hear a difference, even then it's very subtle. 

Dutch and Dutch 8c are coaxial,  their measurements speak for themselves one of the best on axis and off. Linear phase,  constant directivity from 100hz >. 

No, these things don't on their own, make for a better speaker. It's not like this hasn't been studied for years. 

https://www.audioholics.com/room-acoustics/human-hearing-phase-distortion-audibility-part-2

It's harder than not so easy to have time coherence at the listener ears in a home environment unless your room is an anechoic chamber. It impossible because of reflections and the inconvenience of having two ears. 

But the thread is about the time domain performance of a speaker.

One cannot change that too much with DSP. 

With my DSP controlled active speakers I can set them to linear phase or low latency the former is delayed 30ms to align the drivers the later turns off linear phase for a 3ms delay. I can't tell a difference but my room isn't an anechoic chamber. 

You can turn it on and off the Dutch and Dutch 8c as well. They say for certain studio work it might be advantageous to turn it off but in a basic home environment you're probably not going to notice a difference, they recommend leaving it on. I've never noticed a difference.