Coming back to the issue of where to set the LPF of LFE, I happened to come across a series of posts on the subject from 2014. The final one in this sequence is from Mark Seaton. This is from page 526 of the JTR Speaker Thread:
Originally Posted by beastaudio
Quote: Originally Posted by Bunga99
Yep....and few other respected members such as Mark Seaton, Craig John, FilmMixer.
I've tried 120hz and 80hz on the LFE channel and in my room it sounds better with it set at 80hz. YMMV
Agree with that all I do, but you gotta think, if Filmixer and the likes of him are already filtering out above 80hz, by the time that mix gets to the end-user, there already isn't much above to worry about, so the reason to knock it down is that much less important. I will try and experiment with it when I get around to measuring more tonight.
A quick jump in here... Point missed.
Lowering the .1 (LFE) channel low pass (not tied to speaker crossover) becomes less an issue when running subs at perfectly matched levels with mains. As you raise the subwoofer level above a neutral balance, shading/tilting down the upper end makes more and more sense.
Look at the graphic from Craig John's post again:
For a moment forget the roll off an just look at the *difference* between the green & orange curves. The two curves are parallel above the blue line (120Hz), and they converge near 40Hz. Between there is a smooth tapering which makes for a shelf filter. In the case of this 8th order filter, the maximum cut of the shelf is about 8dB as seen between the two curves at 120Hz, with about 4dB of cut around 80Hz. A 100Hz setting makes for about 1/2 those cut values on a similar shape shelf filter.
In many cases, this helps allow for the amped up bass setting while better tapering and transitioning back to the main speakers.
As I and others have posted, this is simply a matter of final "seasoning to taste" in the same manner we might give a modest or aggressive rise to the subwoofer response itself.
To paraphrase what Mark is saying, the more that we boost the bass, the more sense it can make to roll-off the LFE channel a little more with a lower LPF. But, it's still just a YMMV issue.