FAQ: Denon 2500, Panasonic DMP-BD10, Panasonic DMP-BD30 "LFE Bug" - Page 3

OK so where is the extra 5db comes from, remember the receiver will only boost 10db on the LFE and if you need another 5db you need to raise the trim output level for the SW, however the incoming signal already has the redirected bass, so we're back to square one. Unless I'm missing something.

I have a Denon 4806 receiver and the Panny BD10. The Denon doesn't do advanced audio decoding, but does do PCM over HDMI which is how I have my BD10 connected. The BD10 does do TrueHD decoding internally and I'm assuming outputs it as PCM though HDMI. The Denon shows MULTI CH IN when I am playing a TrueHD track (just as it does with a PCM track). I'm assuming I'm still getting the LFE bug with the TrueHD as well?

Yes. Anything output via PCM on the BD10/BD30/2500 will have the LFE bug, whether it started out as a PCM, TrueHD, whatever soundtrack.

So I get old fashioned 5.1 but with proper LFE and Bass Management.

I guess that is better than trying to do a fool around or quasi adjustment method.

And exactly how is it that I get that? Do I use the COAX or Optical out?

OK, thanks. I figured that but just wanted to be sure.

Yes, either of those will output DD.

Once the signal has been "bass managed" by the player, the signal changes from LFE to Subwoofer as far as the AVR is concerned. It may seem like a symantic matter, but it's more than that. The AVR does have a subwoofer trim control, and so do most powered subs, even if there is no means to boost LFE. So it is now possible to bring the "LFE+bass" (aka subwoofer signal) into acoustic balance with the mains.

But Roger, via this method aren't you are still stuck having to manually adjust subwoofer trim +5db/-5db depending if it is a PCM track or bitstreamed TrueHD for instance? Since the Panasonic can't decode TrueHD/DTS-HDMA you are still stuck with the 5db discrepency.

I really appreciate all the help you have provided on this topic and there is some progress here as now at least there is some way to get accurate PCM soundtracks, but with the hassle of having to adjust trim based on source content I would say it still probably just makes more sense to pick the bitstreamed lossy DD track over the PCM track.

What really needs to happen is that Panasonic needs to commit to fixing the issue, even if it is a setup menu "hack" of sorts accessed only by special code or something. The workarounds with this player, unlike the Denon 2500 workarounds which are fine, simply are too cumbersome to be practical.

Agreed. This is a PITA and not something we should have to deal with. Panasonic needs to commit to doing this fix.

See if I got this right, so when the BM is performed in the player the correct balance between the LFE and the redirected bass is restored [LFE-10 redirected bass -5db] the receiver will boost the 10db back by design [well not all of them does that] and the for remaining off balance just adjust it with the SW out trim level on the receiver or on the powered SW's gain control. Is that right?

I'm new so sorry to ask a noob question, but I'm considering this player and not sure I understand in simple terms what the probablem really is? Sounds like it's not accurately playing back the tracks to the right deibal levels? What is the impact to the average listner in the variances we're talking about? I scanned the thread briefly and didn't see an answer to this.

I’m with thehun- this is getting very confusing, and despite lurking here and in the BD-30 thread, I’m still not sure I have this right.

What I should do is:

1. Set the BD-30 to perform BM (Small fronts, 80 crossover). It will only perform BM on PCM tracks, leaving bitstreamed untouched.
2. Set my Denon 3808 to add +5db on the subwoofer channel, but only for PCM, not bitstream (luckily, on the new Denon’s it will remember this +5 db for PCM only, leaving the proper +0db for all bitstreamed content).
3. Set Denon BM to the same small, 80 crossover to avoid redirecting additional bass.
4. Now I have proper output, no compromises, and no manual adjustment needed because the Denon “remembers” the +5db for PCM only

Do I have this right? Is #3 necessary? Normally my cross is at 60.

The very first post in this thread gives a thorough explanation of the issue. Your "thread scanner" must not be working very well if you missed that.

If you consider that explanation to be too complicated, then here's my single sentence summary: "The LFE (low frequency effects) output of the BD30 is lower in level by 5 decibels compared to the other audio channels which means that for some of the audio tracks on a blu-ray disc, the low bass sound won't be as strong as it shoulod be but many people don't even notice the difference." There - I did it in one sentence.

Sorry to confuse- nowhere to set it, but manual does state that the BD-30 will cross at 80 if Bass Management is turned on, so it seems 80 is the crossover you get.

According to the pdf version of the manual, the forced c/o is 100Hz (page 22)... although 80Hz would make more sense...

I saw it, but as requested I wanted a more general explanation of the issue which you proceeded to provide. That's all I was looking for...

I also prefaced by saying I'm new....

Yes.

^^^^^

Ok I got it. So if one raise the SW out that could make the LFE part a bit hot now compared to the RB, but that can be adjusted with at least in my case[and people with Onkyo Integra and Denons] with the LFE pad or trim control since one would need to lower that now. But as you say you can achieve good balance nonetheless. That's complicated but doable. Thanks for a bit of mental excercise.

Has either Onkyo or Denon made a public announcement about this issue? Has Dolby or DTS made an official statement regarding this problem? I have been looking at this most of the day and haven't found any posts or public statements from any of them regarding the issue; I know I haven't looked everywhere... I have seen several people and mags quoting that it was a terrible technical issue and it might not be able to be fixed even on the new BD50...

I assume Panasonic and Denon will be force to quickly fix the problem or do a recall on all of these players. Can we all assume that both Dolby and DTS are requesting that they remove the DD and DTS claims from their advertisements. The manufacturers _might_ be able to claim DD and DTS compliance (I doubt it) but certainly not for trueHD and DTS-HD-MA (both supposedly loseless). I only bought the bd30 because it had the above 4 icons on the box.

The box ought not display a Dolby TrueHD logo, since the player cannot decode it. That could be confusing.

Actually, it only has the Dolby Digital and DTS-HD icons. On the web-site it clearly advertises trueHD


And in the service manual it states:

The issue is not related directly to any of those companies nor their propreatery formats. Dozens of companies flunked on correct LFE levels in the past mostly on receivers, and I don't remember if Dolby or DTS had ever been involved, but quiet frankly other then consulting, they probaly won't, nor they should. THX is far more "unforgiving" on these type of issues.

I know you and Roger are not speaking on behalf of Dolby Labs. I am suprised that you belittle Dobly certification, I have always held it in higher esteem than what you just implied.

I have just read two interesting posts in the 1.4 upgrade thread, one stating that according to Panasonic they were in the process of testing two 'fixes' for this problem which flies in the face of several comments by Roger; the other one stating that Panasonic doesn't need to worry about it and they are not going to fix it, which closely agrees with Roger's just previous statement and which I now fully believe.

This is no longer a significant issue for me, I have decided to vote with my wallet and return the bd30, either tonight or tomorrow as I am in the last couple of days of my BB 30-day return period.

Little birds tweeting.

I'd love to be wrong.

Cryptic, yes.. explain it, no

ah, so we're getting a firmware fix. That, or FilmMixer is having a stoke. Or both, I can't tell.

Nice that my upgrade to the Integra 9.8 has encountered this problem, as I was previously running analogue from the BD10.

(*shaking fist*)
DAMN YOU SALAZAR!!!!

Roger is representing Dolby, that should be pretty clear to anyone.
As for me I don't "belittle"[spelled DOLBY] or any other company or their intelectual property, you simply making a "straw man" argument which I"m simply not gonna worry about much. Good luck with your search for the next BD player.

As clear as it may sound to you, Roger did in fact make it very clear in earlier posts that he was not speaking on behalf of Dolby Labs. I am sure he is just posting in these forums as any other informed enthusiast might do. I, for one, really hope he continues to do so - his 'qualified' enthusiasm is terrific. I work for a very large technical company and have no rights to speak on their behalf, just as I am sure that Roger would never do.

BTW, I am looking at the Panasonic BD30 in black box mode... I am expecting (according the user's manual) that if I play a DD trueHD track and the player is set for PCM, I should get DD 5.1 on the other end (the DD certification would then be fine!). However, with Panasonic's decoding of 'trueHD' and re-encoding of 'DD 5.1' tricks (SPECIAL NOTE: they fully admit that they are decoding trueHD and are encoding DD 5.1), I wind up with something that is not an accurate DD 5.1 signal representing the original input. As far as I can tell, Panasonic's DD 5.1 encoding is severely flawed (if trueHD is truly a loseless representation of the original audio, as promised).

Why would they? There is no licensing/standards/logo organization for uncompressed PCM. Absent that, it certainly doesn't default to Dolby Labs or DTS. This should come down to the film industry's creative community and A/V enthusiasts on one side and manufacturers on the other. And I'd really like to see the A/V industry press speak up.

While I am hopeful for an easy firmware fix, I fear that the marketing/PR departments are brainstorming right along with the engineers.

Despite my returning my BD30 due to the LFE bug, I'd be very happy for BD30 owners if they got a fix for two reasons.

1) Hey, they get their player fixed and outputting proper LFE levels as should be the case with a $500 player!

2) And, perhaps more importantly, it means that the upcoming BD50 I plan to buy (assuming its fixed) will likely be fixed, too!

Could you let me know how the DD is unfaithful? I was not aware of any problem there.