There is huge difference between using a 50hz xover and 80hz xover, mainly in the tightness and transient response of the bass. Even though they measure identical, a 80hz xover sounds loose and sloppy, where as a 50hz xover sound tight and snappy. I took a few measurements and am at a loss as to why the sound is so different.
All of my speakers except for my height speakers manage -3dB @ 50hz in room. Originally I had my xover set to 80hz, because when I was using Klipsch R-15m's, there was a good deal of port noise above 85dB below 80hz, with my system now using Reference premiers, port noise is non existent with the tractrix shaped port. I get exactly the same frequency response with a 50hz xover vs an 80hz xover.
Keep in mind the wild dips and peaks are simply room interactions, which obviously change depending on the mic position.
Distortion @ 95dB (my max listening volume for movies, i.e. -10dB on the knob) is almost identical at 50hz as well, so I doubt either the sub or the speaker would do a better job at reproducing distortion free bass within their bandpass.
-10dB (95dB @ the listening position) on the receiver.
(keep in mind I didn't calibrate the spl on the mic)
I did not include center channel measurements because REW crashed when I went to save them, and I am far too lazy to redo it
but the THD is .98% @50, likely due to dual woofers.
Any idea why it sounds so much better letting the speakers handle 50hz+?