Well, the LFE high end spec is 120 Hz. I wonder if the 990 is just cutting that signal as dictated by the crossover frequency.

I've wondered about that before, as I generally run a crossover point at 40 Hz. I run the sub as L/R+LFE [or whatever the term is]. I "assumed" that I would get the *entire* LFE channel [even if it's > 40Hz, which it certainly *can* be], as well as any L/R information that's < 40 Hz. However, it seems like you are debunking that.

If my initial assumption were correct, I would think that they might send that to the mains [the stuff that's cut out of the LFE channel at the crossover point]. That way, the integrity of the initial signal's frequency response will still be maintained.

If they are just tossing the LFE as cut off by the crossover, then I think there may be a problem...

In my mind, the crossover points are implemented to separate parts fo the spectrum that the mains, center and surrounds can't handle. I don't think it should limit the range of the LFE signal.

If it's desired, perhaps a crossover for the LFE channel could be implemented separately from those for the mains, center and surrounds.

I also think there should be an LFE trim, in addition to the sub out level control.

Well, I had basically the same question to Outlaw a while back. Their answer on June 4th, 2006 was the following...
I might have to do some testing of my own. Personally, I don't want to lose any LFE info and I wonder why the output level varies during your tests.
Sadly, I don't have a DVD burner nor do I have any other DVD with a single LFE track test tone.

Most of the Pixar, Disney DVD, and I believe LucasFilm (i.e. Star Wars) movies come with the "THX Optimizer" in the extras. I believe there is a LFE test tone in there. It's nothing fancy but is better than nothing. It's a hidden tool most people don't know they have.

Duh, I wasn't thinking. For some reason I was thinking I needed a sub-tone via a Dolby Digital track at one specific frequency. That's not the case to do this test. But, I used a THX test disc as was suggested.

For all testing, I turned the amp off that powers my 5 channels and left only the sub on.

Running a Dolby Digital test via THX Optimizer on The Incredibles...
-It didn't matter if my mains were set to large or small, the crossover drastically modified the output on my sub when the THX optimizer was sending an LFE signal.

I decided to take it a step further and go analog and play an SACD, unplugging all analog inputs from my player to the 990 except leaving the subwoofer analog input connected. I wanted to do this to ensure bass from other channels wasn't getting mixed in to the subwoofer out on the 990.
-Essentially the same thing. I played Dard Side Of The Moon with the deep bass on the first track and switching the crossover drastically modified the output on my sub.

The change in subwoofer output on both tests was audible and I could measure it with my SPL meter.

I guess what this boils down to is that the 990 does apply a low pass crossover on the LFE channel. Needless to say, I will be leaving my crossover set to 120Hz due to the standard. I don't wanna lose any bass

If the LFE is being low-passed as dictated by the crossover, then I'd say that a bug, especially with the answer quoted from Outlaw above. Has anyone logged a help ticket for this?

Bummer.

I went ahead and did. But, others please feel free if you so desire.

Cool! Let us know what they say. Thanks!

I did some more testing with my test DVD. My DVD has specific LFE frequencies that are encoded in Dolby Digital. I did this test with the fronts set to large and the sub set to LFE Only. With the xover for the fronts set to 40Hz I played the LFE test tone of 40Hz and it played fine through the sub. When I played the 70Hz tone I could barely hear it. When I played the 120Hz tone all speakers were silent. Then I set the xover for the fronts to 200Hz and played all the tones from 120Hz on down and all played at about the same level measured with an SPL meter.

This confirms that the xover for the fronts is being applied to the LFE channel. This is definitely a bug that needs to be fixed.

If you have the xover for the fronts set to anything below 120Hz you are missing some of the LFE when listening to a Dolby Digital sound track. This is true no matter if the fronts are set to large or small. Even if the sub is set to none, any LFE frequency above the front xover freq is being cut off and lost.

Has anyone heard an answer back on this one yet?

I emailed after a couple of weeks had passed and I hadn't heard back. I did get a reply stating they had their software team looking at it and that a solution might be available in the not so distant future (this was on 5/18).