Hi Jason and all,
Here are some informed comments on group delay at low bass frequencies. I posed the question to Tom Cumberland, Axiom's chief R & D engineer, who answered me this way:
"The issue of group delay can best be explained by moving a sub one to two feet in a given direction. This being said, there is group delay in everything that relates to room placement. Whether a sub is ported or sealed only affects its overall frequency response. Of course, a smooth linear response is the optimal performance from any loudspeaker. Simply moving a subwoofer around the room creates group delay. This movement, of course, helps remove the nulls and peaks in the frequency response in the room whether it is one sub or multiple subs."
I think this is helpful. There may be updates to this as I learn more.
Regards
Alan
