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[Tim McCulloch]

Tim, I take that to mean once the mains and subs are playing well with each other (as in phase and aligned with each other), then timing them as a group vs other sound sources such as stage, delay towers and other ‘zones’ that the sound may overlap in.

No, you are conflating several different things.

Not the best article on the subject, but perhaps easier to grasp:

https://en.wikipedia.org/wiki/Group_delay_and_phase_delay

Anything that affects frequency will affect time - minimal phase relationships.  As phase IS time, think for a moment about the various filters used in loudspeaker processing, specifically the high pass filter on a subwoofer.  If you high pass the subs at, say, 30Hz, how long does it take for the signal to exit the filter?  How steep is that filter (i.e. how many poles)?

[Geert Friedhof]

With active speakers all bets are off. Especially with FIR filering , 48k against 96k etc. Not only that, but tuning freq, port length also play a big part in this. So it might be better to invert the polarity of the bass or the top instead of/combined with delaying one or the other.

[Ivan Beaver]

No, they do not.
(in a rather simplistic way)
In a perfect world, the magnets on all the drivers would line up with each other, and no time correction would be needed.
In the real world, you have positional differences, path length differences (especially with bass horns) and these are where the corrections are needed.
"speed" of any frequency is exactly the same.

ONLY IF the "real world" does not have any crossovers involved, and the phase angle of the drivers is the same.

Since neither of these exists, there will be different amount of delay times, based on more physical and electrical issues

It is a "nice idea" to physically line them up, but in REALITY, that never happens.

The HF will always be behind the lower freq bands in time-physically, because the lower band have more "delay" built into the drivers and the electonics

[Tim McCulloch]

ONLY IF the "real world" does not have any crossovers involved, and the phase angle of the drivers is the same.

Since neither of these exists, there will be different amount of delay times, based on more physical and electrical issues

It is a "nice idea" to physically line them up, but in REALITY, that never happens.

The HF will always be behind the lower freq bands in time-physically, because the lower band have more "delay" built into the drivers and the electonics

And then the question becomes one of "impulse alignment" or "phase alignment".

Gotta stir the pot one more time

[Mark Wilkinson]

And then the question becomes one of "impulse alignment" or "phase alignment".

Gotta stir the pot one more time

Ah yes, but once clearly seen, they become the same thing .... 

(Any room around the pot for another cook-stirrer?)   

[Ivan Beaver]

And then the question becomes one of "impulse alignment" or "phase alignment".

Gotta stir the pot one more time

I prefer phase alignment (NOT to be confused with polarity).

[Mark Wilkinson]

I prefer phase alignment (NOT to be confused with polarity).

A great article on sub alignment IMO...
http://www.excelsior-audio.com/Publications/AES_NAMM_2018_Subwoofer_Alignment_with_Full-Range_Systems,_rev02.pdf

[Tim McCulloch]

Ah yes, but once clearly seen, they become the same thing .... 

(Any room around the pot for another cook-stirrer?)   

It depends on which direction you stir first as to how long it takes to get to the Same Old Place (obscure Fire Sign Theater reference).

A system with very good phase alignment will also exhibit good impulse alignment...

Next!

[Geert Friedhof]

I prefer phase alignment (NOT to be confused with polarity).

With a sealed cabinet phase alignment should be easy enough, but with a br design, near its tuning freq?

[Mark Wilkinson]

With a sealed cabinet phase alignment should be easy enough, but with a br design, near its tuning freq?

Don't understand.......What possible alignment, what handshake between sub and main, could ever be going on down at port tuning frequency?

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