I was using a test DVD with some test tones for LFE and I was messing with bass management on the 990 and discovered a problem. My mains are set to Large and sub is set to none. I was listening to a LFE test tone designed to adjust the level of the LFE channel and changing the crossover when I ran into a problem. When I change the crossover for the front L/R the output level of the LFE test tone changes. If it is set to 40 the level is low. As I increase the crossover freq the level increases and I hear higher pitched sound. Why is this? If the sub is set to none then the crossover freq shouldn’t make any difference whatsoever. If this is working as designed what should the xover freq be set to?

So, you're running an LFE signal into the system with mains set to "Large" and sub set to "None", right?

Is the sound then coming out of your sub or your mains?

How are you generating this signal? PC? DVD?

The way you have things set up, I would expecting nothing from the sub and no change in the mains output as crossover frequency is changed. I'm assuiming all other speakers (center, rears, etc.) are off.

I'm using a test DVD. It is a DD signal and the tones are designed to adjust the level of the LFE to match the levels of the other speakers. The LFE channel is being sent to the Fronts but it changes when I change the Xover freq for the fronts. Again, the fronts are set to "Large" and the sub is set to "none". I have a sub but I can't seam to get it set the way I want it. My fronts are solid down to 35hz and they sound best when fed a full range signal so I was just experimenting when I ran into this. I have a sub but it wasn't connected at all when I was trying it this way.

No sound is coming from the center and rears when listening to LFE test tone.

Hi Daryl,

That definitely sounds like a problem. What "mode" is in in at this point? "Dolby Digital"? If you are just playing this one signal through the 990, and mains are set to large and the *only* change you are making is crossover frequency, and all other speakers are off, then you should hear no difference in the main output.

I see you had input on my thread here: http://ubb.outlawaudio.com/cgi-bin/ubb/ultimatebb.cgi?/ubb/get_topic/f/34/t/001287.html

Steve at Outlaw is working to replicate the issue. If you look at my last post at that thread, there is a link to some frequency sweeps. Do you have the setup to do some type of measurement like that?

I have a Radio Shack SPL meter and the test DVD I was using yesterday was one I downloaded that was created by swithey at AVS.

http://www.avsforum.com/avs-vb/showthread.php?t=742969

It has tones to help calibrate your sub (2 channel PCM) and a different set of tones to cal the LFE, which is a Dolby Digital signal. It was when using the LFE tones that I ran into this problem.

Interesting situation. Just for clarity, when you are running the tone can you hit Dolby Modes once to ensure the display on the 990 actually reads out DOLBY DIGITAL? It just might be something to ensure to aid in troubleshooting. The only reason I mention it is because I have situations where I put in a DVD, choose the Dolby Digital track for the movie, the movie starts, and it is in Pro Logic (not DD). If I hit Dobly Modes it'll go into DOLBY DIGITAL and in fact I can't go back to Pro Logic.
But informing Outlaw of exact processing modes might help Outlaw in troubleshooting.

Yes, I have hit the Dolby button and the 990 reads Dolby Digital.

Last night I did more experimenting. I connected the LFE/sub rca jack
on the back of the 990 to the LFE input on my sub. I then set the sub
setting in the 990 to LFE Only and left the fronts at Large. Then I
played the LFE test tones from the test DVD again. All the sound was
coming from the sub as expected (the rest of the speakers were silent)
but if I increased the Xover freq for the fronts the sound got louder.
During this test I hit the DD button on the remote to make sure the 990
was reading Dolby Digital and it was. I also set the sub setting
on the 990 to LFE+L/R and the result was the same. I even set the Front L/R to small and the result was still the same.

Hi Daryl,

So...

You are sending an LFE signal to your 990. Mains are set large, sub is set to LFE.

All sound comes from sub, all other speakers are silent (what is the crossover frequency at this point?)

You increase crossover frequency for mains and the sound gets louder. (what's the crossover frequency at this point?)

Does the sound ever come from the mains? Or it just gets louder in the sub?

Sending a Dolby Digital LFE signal using a test DVD. Mains are set to "Large" and sub is set to "LFE Only".

The LFE test tone comes from the sub only no matter what I set the front xover freq to.

The sound gets progressivly louder as I increase the xover freq. In the end I left it at 40. If I change it from 40 to 200 it sounds so much stronger that I'm afraid that some damage may occur to my sub.

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).

I think we're all very intrested in seeing this one resolved. I only amazed that none of us noticed this problem sooner.

If they're making a firmware update, I wish they could sneak in another little thingy. I continue to have issues with my 990 not locking on to a "Dolby Digital" signal so I am constantly hitting the "Dolby Modes" button to display what setting it is on.
I wish that you could set something to tell the 990 to always display the processing mode rather than the current input.
Sorry, probably shouldn't derail the thread

What the heck, let's derail this puppy for a second...

The problem with not locking onto DD signals seems a bit odd sounding to me. What does it do when it has a problem?

While we're derailed, a setting to briefly replace the input display with a scroll showing the incoming signal type (PCM stereo, DD 2.0, DD 3/2.1, DD EX, DTS 3/2.1, DTS ES, ...) and processing being applied (DD+PLIIx-Movie, ...) would be sort of neat. Similar to the way the 950 would show the incoming signal format briefly before reverting to showing the processing mode.

Okay, when I hit "Dolby Modes" often it will say "Dolby Digital" as it should. But, sometimes it will say "Pro Logic" and if I quickly hit "Dolby Modes" again it will switch to "Dolby Digital" as it should've been in the first place. Then what is more odd is that if I subsequently hit "Dolby Modes" again it will not allow you to switch back to "Pro Logic" as though it is being forced on "Dolby Digital".
It will do this on a various high-def channels and if I try to navigate to another channel which is not a Dolby Digital broadcast, and then immediately flip back to the original channel that was giving me problems, for some reason it defaults just fine to "Dolby Digital", unlike what it did the first time.
It's really frustrating. I think I have had it happen to me on a DVD once or twice also but it is random and I don't watch DVDs nearly as much as TV so it more rarely occurs there. Almost always I cannot replicate it. It'll just do it sometime down the road (an hour later, a day later). Just random.
I wish I could find a pattern, but I can't.

There may actually be a good reason for it. Dolby Digital can be 5.1 or 2.0 (or a number of other options), and the different options will have different surround mode preferences saved. With HD channels, you can get a wide assortment of situations (ads typically run Dolby 2.0, shows themselves as either 5.1 or 2.0). I usually tell the difference by watching the LFE indicator (located under the "SUB" indicator and above the back surround indicator on the speaker display at the left side of the front panel) to differentiate between Dolby 5.1 and 2.0 (the LFE light will be on for 5.1 sources but not 2.0 sources). I assume you've got the 3.11 firmware installed?

Yeah, I have the latest firmware installed (if that's the one that lets you display the processing mode without changing it).
I just now turned on the system, went to MHD (Music High-def), the LFE indicator was on, I hit "Dolby Modes" and it displayed "Pro Logic". I hit it again and it flipped to "Dolby Digital" and the LFE indicator is still on. Now hitting "Dolby Modes" does not allow me to go back to "Pro Logic" (not that I want to). It's just weird that it is stuck on "Dolby Digital" yet originally it was on "Pro Logic".
Now if I flip to a regular channel it goes to "Pro Logic" (as it should) and if I flip back to MHD it defaults to "Dolby Digital" like it should. So why didn't it the first time?
That's why I have problems replicating it or finding patterns.
And it doesn't do it only upon initial startup. I'm sure at some point this evening when flipping channels I will witness it again.

Regarding the LFE issue, I know Outlaw has said they're working on it but I wish they'd at least list out what exactly they're working on. In other words, list the changes they're going to make. Maybe they don't know exactly due to a deadline of some sort and things included just depend on what they can get done before the deadline.
I know they want to take their time and get it right, which is a great thing. But knowing the specs of what the update will include certainly would calm my nerves
What if the "fix" changes something else that I don't want to change?
I know, patience, patience. Just trying to relax the anxiousness.
I think they ought to fix that other issue when you run auto-setup and your speakers are already set to small with a high-crossover and it gives you an error saying you need to flip your back speakers with the fronts.

Daryl - Otto,
Just for clarification:
The crossover/LFE issue is only affects Dolby Digital.

NOT DTS, 2-Channel downmix or 2-chanel inputs?

Thanks

I don't have a test disk with DTS encoded LFE tones so I can't confirm. I didn’t test in 2 channel down mix mode.

The one thing I do know is that the bass management doesn't work at all as advertised. It is impossible to configure the 990 to take advantage of a sub for both movies and music. The advertised bass management feature of the 990 was a major reason I purchased the 990 along with some other features and those features are un-usable.

I know you addressed your question to Daryl and Otto, so I hope you don't mind me replying. But, as indicated in this post , it does effect analog also. The post refers to the 7.1 analog-in. Although I didn't test it, I would bet it effects standard 2-channel analog inputs as well.

Thanks for the updates - jrlouie and Daryl.
Later....