@bdp24 Can you tell us more about the continuously-variable phase control. I researched a DIY phase control solution (not just a 180 switch) awhile back and couldn’t find anything on it. I actually convinced myself that the continuously-variable dials I see on subs aren’t doing what they say they do. Haha! So... they do exist? How in the heck do they work?
Group delay in subwoofers
I understand the phenomenon of group delay when subwoofers are connected to a preamp and that they need to be placed approximately 8 ft closer to the listener than the mains. Is this also the case when connecting a sub through the speaker level inputs from an amplifier or is group delay much less of an issue in this configuration?