Yet another complication of LFE+MAINS concerns speaker level calibration vs real material.

There are various calibration sources: built-in receiver test tones, built-in player test tones, DVD cal discs like Avia, etc.

If you don't know exactly how the LFE+MAIN bass management works for the calibration method you choose, you could easily get bass doubling.

E.g. Using either Digital Video Essential or my Dolby calibration disc, there's no difference in bass output when switching from LFE=BOTH to LFE=SUB (with FRONT=LARGE). No difference audibly or on a meter. Say you have LFE=BOTH, FRONT=LARGE and set subwoofer levels based on this.

Then you play real material, say a CD. I have some organ music that outputs constant low freq notes -- easy to measure bass output on that. While playing that, if I switch from LFE=SUB to LFE=BOTH (with FRONT=LARGE), bass output goes way up -- classic bass doubling.

It is the worst possible situation -- a behavior variance between calibration and real material. That effectively means I can't calibrate bass levels with LFE=BOTH and FRONT=LARGE.

This stuff should be so easy, but the mfgs through poor documentation and lack of standardization make it very complex. And I've worked with this stuff for years -- I can't even imagine (say) my wife tackling this.

And that doesn't even include the SACD bass standardization problems, or other setup/calibration complications from multichannel analog sources.

If the home theater/surround/media vendors want broader acceptance of this stuff, they need to do a better job of documentation and standardization.