I see... so "corking" the base port gives more of a sealed speaker effect? If I understood it correctly.
It does, but it's moot. Group delay is only audible in the most severe cases, and to be severe enough to be an issue the speaker design is intrinsically flawed and other issues would dwarf group delay. Much ado is made about group delay in some circles, but not by those with a good understanding of what it is.
That would only be the case if the mains were being run well below the box tuning frequency, where they shouldn't be run anyway. Even if you don't know what that tuning frequency is Audyssey etc will, because along with phase shift below Fb there's also a precipitous drop in sensitivity and output.
Pretty much, but unless you're running them full range, or lower than you probably should when using subs, you shouldn't notice any difference.
I would agree if we were talking about a single speaker with one port. But in this case you are matching a mid-hi system with a low system and comparatively the differences, albeit small, will cause smearing if the difference is large enough.
Audyssey can only set the phase relationship at one point. If the main speaker is tuned low enough I agree there will be no problem but if the port tuning is close (within 1/2 octave) to the crossover point then the relationship difference can be audible.
The other respondents have hit on most of the reason, but there's one more - power handling.
That's really not the case. First off, when you limit excursion you also limit low frequency output. To counteract that one will probably use EQ to get the lows back again, and every 3dB of EQ boost doubles power. Second, a driver in a ported box has minimal excursion near the tuning frequency, where the port is doing all the work, while the cone barely moves. Between those two factors ported boxes have considerably less excursion than sealed in the lows. If you compare them at higher frequencies, an octave and higher above the tuning frequency, the excursion of sealed and ported are the same.
That can occur, but more often than not it doesn't. The low frequencies that come from ports radiate omni-directionally, so where the port is on the cab seldom has any influence on response.
Agreed. You'd need to change box size to see any change in power handling...
Power handling in and of itself doesn't matter that much anyway. You can make a box smaller, and in so doing increase the low end displacement limited power handling, but at the same time lose low frequency sensitivity, so the net result is a loss of maximum low frequency SPL. That's why when modeling a speaker the second most important chart after small signal SPL is maximum SPL, which takes into account frequency response, sensitivity and both thermal and displacement limited power handling.
It depends how the speakers interact with the room you are in.
That is a very informative graph and analysis you have there. May I ask what setup you used to perform this measurement?
