Denon 3805 Bass Management Problem

This being my first post, I originally put my message under the "Exclusive Denon AVR-3805 First Look!" thread. Not knowing how else to move a thread, I hope I am not doing something very bad!
I need some opinions before sending my unit back to Denon.

Here is my original post,

Hi,

I'm a new comer on this site...and I need help with a strange problem that I have.

My Home Theatre setup is built around the AVR-3805/DVD-5900 combo. My
problem is as follows:

The Sub woofer (Paradigm servo-15) will not come on with all analog 2 CH sources (CD, DVD, TV,Tuner) when the receiver is in Dolby PLII (5.1 setup) Music/Cinema or DTS NEO Music/Cinema. The speaker setup is; FL=FR=C=LARGE and SUR A=Small.

All Digital sources (DTS or Dolby) run normally with the same speaker
setup.

The sub woofer mode is set to LFE in the 3805 settings.

If I set the Centre speaker for example to Small then the sub comes on.

I have read the Denon book (French and English version) so many times I am
sick of it....I did check the setup many times. I also tried to replace
the subwoofer cable. I also tried the microprocessor initialisation as
per page 87 instructions in the manual. Locally I did not find any
answer yet either from the dealer or Denon Canada (phone conversation).
I am hoping that you will come up with a good suggestion because I don't
really want to send the unit back for repairs and be without it for a
long period. I really hope you can help me.

BTW, a friend of mine has the same equipment and he does not have the same problem.

Anxiously waiting for help,

Thanks

Seismo

I thought this question was answered in the other thread you mentioned but perhaps you missed it.

Here are the relevant notes straight from the manual. The receiver is working fine - your setup is incorrect for what you want to achieve.

NOTES:
• The only signals produced from the subwoofer channel are LFE signals (during playback of Dolby Digital or DTS signals) and the low
frequency signal range of channels set to “SMALL” in the setup menu. The low frequency signal range of channels set to “LARGE” are
produced from those channels.
• For speakers set to “Small”, sound with a frequency below the crossover frequency is cut, and the cut bass sound is output from the
subwoofer instead.
(• When the subwoofer set to “NO”, the bass sound is output from the speaker set as “Large”.)
• The subwoofer mode setting is only valid when “LARGE” is set for the front speakers and “YES” is set for the subwoofer in the “Setting
the type of speakers”. (see page 31).
• When the “LFE+MAIN” playback mode is selected, the low frequency signal range of channels set to “LARGE” are produced
simultaneously from those channels and the subwoofer channel.
• Selection of the “LFE ” play mode will play the low frequency signal range of the channel selected with “LARGE” from that channel only.
Therefore, the low frequency signal range that are played from the subwoofer channel are only the low frequency signal range of LFE (only
during Dolby Digital or DTS signal playback) and the channel specified as “SMALL” in the setup menu.
• When the subwoofer is set to “Yes”, bass sound is output from the subwoofer regardless of the subwoofer mode setting in surround modes
other than Dolby/DTS.
• In surround modes other than Dolby Digital and DTS, if the subwoofer is set to “YES”, the low frequency portion is always output to the
subwoofer channel.

This is standard bass management stuff, although I admit the manual is a bit confusing the way they describe things.

1. Make sure you set subwoofer=Yes in the speaker configuration setup. If subwoofer=No, only the Large speakers will get the bass below the crossover point.

2. The manual says that the 'subwoofer mode' is only applicable when speakers are set to Large. When sub=yes, some speakers are set to Large, and LFE is set for the subwoofer mode, the sub will get LFE ONLY. The Large speakers will get all the non-LFE channel bass. If you set it to LFE+MAIN, then BOTH the subwoofer and Large speakers will get the LFE. This only applies to DD and DTS because only those formats have an LFE channel.

3. Speakers set to Small will get all bass below the crossover frequency as long as subwoofer=Yes.
It's no suprise the sub became active when you set the center to Small - it is now getting the redirected bass from the center channel.

Unless you have floorstanding front speakers that can truly go very low in the bass range, you should set ALL speakers to small and subwoofer=yes - then the sub will get all bass below the crossover frequency AND the LFE when you are playing DD or DTS tracks.

I was actually going to ask this same question. I had my receiver set to "LFE+MAIN" and I just switched it to "LFE (NORM)" and the bass sounds much more uniform now for some reason. Do these "subwoofer" settings also apply for regular 2-channel audio as well? It seems like the bass blends much better as well with this setting when playing a CD.

Thanks again Anonymous,
As I mentionned all digital modes are fine with proper sub operation, but where I am missing the sub, is in surround modes other than Dolby Digital and DTS.

As outlined in your last point:
• In surround modes other than Dolby Digital and DTS, if the subwoofer is set to “YES”, the low frequency portion is always output to the
subwoofer channel.

If only the surround speakers are set to small should I not get the sub to come on to take over the low frequency below the crossover point (80 hz for example)?

Unless I don't understand your point 3. below.......

3. Speakers set to Small will get all bass below the crossover frequency as long as subwoofer=Yes.
It's no suprise the sub became active when you set the center to Small - it is now getting the redirected bass from the center channel.

Seismo

My Turn

Hey Seismo,

As a fellow 3805 owner, I'm going to take a crack at your problem...I'm not really an expert, but I managed to get sound that I like -- and my sub performs in all modes.

Based on the settings you described (Front = Large, Sub = LFE Only) then it's no surprise your sub isn't active for non-DD 5.1, non-DTS or DTS-Neo settings.

That's because there is NO dedicated LFE channel on those settings, as I understand it. Nothing is being sent to your sub.

If you set your Fronts = SMALL, then the cross-over works to send the lower frequencies (as you specify) to the Sub. But when Fronts = LARGE, then the receiver sends all freqs to the fronts, and only sends the ".1" of the 5.1 mix to the sub -- but in the modes you describe, there is no ".1" channel.

If you set your Fronts = Large and set the Sub = LFE + MAIN, then your sub gets whatever low frequencies it can handle -- but so do the fronts.

So, to solve your problem, set your Fronts = SMALL ... OR set your SUB = LFE + MAIN, and you should be ready to rock!

I hope this helps... it is totally confusing and one of the hardest things for me to try to figure out. It's not like the 3805 manual was written for humans or anything...

Good luck!

Unless your speakers are capable of producing true 20hz-20khz signals, I suggest all speakers set to small configuration. The 3805 has a great crossover for this option. Just set the crossover at a very low frequency (say 40hz). VERY FEW speakers (L+R) are capable of producing sub 30hz notes at the same levels a dedicated subwoofer is capable of. Anonymous did a great job of explaining "bass management" architecture. In those modes (other that DD, DTS) the bass will act like stereo for the most part, only coming from the required channels when (other speakers) set to large.

Seismo,
These two statements from the manual are the source of confusion because the second one is actually incomplete. Denon should have added the words I put in bold. Geez, no wonder people complain that the Denon manual sucks. Bass mgmt is complicated enough without them making it more so.

* For speakers set to “Small”, sound with a frequency below the crossover frequency is cut, and the cut bass sound is output from the
subwoofer instead.

* When the subwoofer is set to “Yes”, and the speakers are set to Small, bass sound is output from the subwoofer regardless of the subwoofer mode setting in surround modes
other than Dolby/DTS (the subwoofer mode is only applicable when speakers are set to Large and only controls how LFE is to be routed between the subwoofer and Large speakers.)

Here is my attempt at simplifying it via a simple table of options: (assuming subwoofer=yes in setup).

Small speakers
Any surround mode (even Stereo) applied to a format that does not have a .1 channel (DD 2.0, analog 2 channel from a VCR or set top box, 2 channel PCM from a CD, etc):
Subwoofer will get all bass below the crossover frequency for each channel that is set to Small.

DD or DTS: Subwoofer will get all bass below the crossover frequency for each channel that is set to Small AND the LFE if the format includes an LFE channel (DD 2.1, 5.1, 6.1, etc; likewise for DTS).

Large speakers
Subwoofer won't get any bass from any channels set to Large - the Large speakers get a full-range signal.
-->Subwoofer mode=LFE: For DD or DTS with a .1 channel, the sub gets the LFE.
-->Subwoofer mode=LFE+MAIN: For DD or DTS with a .1 channel, the subwoofer gets the LFE AND the Large speakers get the LFE (in addition to the 'regular' bass they are already getting).
--> For non DD or DTS, there is no LFE channel so the subwoofer mode setting is ignored - the Large speakers still get a full-range signal.

- If you want the subwoofer to play the bass (non LFE), you must set the speakers to Small.
- If you want the other speakers to play the bass (non LFE), set them to Large.
- If you want the sub to play the LFE only, set the speakers to Large and the subwoofer mode to LFE.
- If you want the speakers to play the non-LFE bass AND the LFE bass, set the speakers to Large and the subwoofer mode to LFE+MAIN.

For most setups, all speakers Small and Subwoofer=yes is the best setting. Even if the front speakers can reproduce bass very well (the reason for setting them to Large), it is often better to set them to Small anyway and relieve them of the burden of playing the low bass - that's what subwoofers do best.

Edit: Sorry If I stepped on anyone's toes. Others were adding correct information at the same time as I was typing.

Anonymous,

Way to go on super simplifying it. I sometimes lack that ability. Assuming one has the receiver in question, one would be an idiot not figure it out now. (Sorry if anyone cannot, I really do mean any one person is an idiot. This hobby can be a tough one to pick up. Especially the nomenclature. )

Its tough oin anybody that has to use the Denon Manual. This is my second.

Anonymous said:

Seismo,
Small speakers
Any surround mode (even Stereo) applied to a format that does not have a .1 channel (DD 2.0, analog 2 channel from a VCR or set top box, 2 channel PCM from a CD, etc):
Subwoofer will get all bass below the crossover frequency for each channel that is set to Small.

Click to expand...

But if the front channels are set to large, center and surround channels set to small, and you are playing 5/7CH mode, or PLII, PLIIX etc., will the subwoofer get anything?

Thanks

PENG said:

But if the front channels are set to large, center and surround channels set to small, and you are playing 5/7CH mode, or PLII, PLIIX etc., will the subwoofer get anything?

Thanks

Click to expand...

Yes, it will get the bass below the crossover frequency from the center and surrounds channels.

First, thanks everyone for your input.

Secondly, let's get something clear. This thread is strictly technical by that I mean that I understand very well the "Standard Bass management Stuff". This thread is not about whitch crossover point is best or how to setup individual speakers (large or small).

You know Anonymous, it's funny because I agree with all you wrote about Bass Management and system setup. I guess I am a very poor writer, not being able to get my point accross, yet. So, not to waste your time on this subject, this will be my last post on this subject.

If there is a brave Denon 3805 owner willing to try the following setups, I would greatly appreciate you try it.

So here goes: Pick your favorite CD (stereo) and use Dolby ProLogicII Surround mode and configure the receiver as follows.

Setups:

1) Sub=Yes
Sub mode=LFE
CrossOver=80 Hz
FL=L
C=S
FR=L
SL=S
SR=S

2) Sub=Yes
Sub mode=LFE
CrossOver=80 Hz
FL=L
C=L
FR=L
SL=S
SR=S

My answers:
setup1 = SUB ON
setup2 = SUB OFF

Seismo

Seismo, did you notice that I asked Anonymous your setup 1) as well, and he must have answered it correctly because you gave the same answer.

I must admit I have not tried your setup 2) but you got me so curious I am going to try it right now.

I just tried it, Seismo is right. However, with setup 2), the display did indicate the subwoofer was on, just that there was no sound coming out of the sub.

When 5/7CH Stereo mode was selected, even with setup 2), I was getting bass to the subwoofer. So it is possible that everyone is right, but in non DD, DTS surround mode (PLIIX, NEO6 etc.), there may not be any intended bass signal going to the surround channels to begin with. This gives the impression that the sub is "off", when in fact it is technically "on", but there is simply no intended bass for the .1 channel in non DD, DTS mode.

At the risk of beating a dead or dying horse to death, here is what I think is going on:

(All of this is predicated on the source being a 2-ch. analog source, and ProLogic II decoding being used to provide 5-ch. output to the speakers (or 7 ch. in the case of PL IIx) - in other words, no dedicated LFE 0.1 channel.)

In scenario 1, you are getting low freqency bass (below the cross-over freq.), redirected from the center and surround channels, which are set to small. Practically speaking, this is almost all going to be from the center channel.

In scenario 2, in theory the sub would still get low-frequency content that was intended for the surrounds, redirected to the sub. But, maybe there isn't any low-freq. content intended for the surrounds in the first place.

PLII (and IIx) are described on the www.dolbylaboratories.com web site as providing full-bandwidth channels. But, that may depend on how the 2 ch. analog source signal was mixed in the first place. If there's little or no low-freq. content on the surrounds, an auto-signal-sensing sub might turn off if it is only the surrounds set to small. Possibly with different content the sub might turn on in the scenario 2 set-up.

PENG said:

I just tried it, Seismo is right. However, with setup 2), the display did indicate the subwoofer was on, just that there was no sound coming out of the sub.

When 5/7CH Stereo mode was selected, even with setup 2), I was getting bass to the subwoofer. So it is possible that everyone is right, but in non DD, DTS surround mode (PLIIX, NEO6 etc.), there may not be any intended bass signal going to the surround channels to begin with. This gives the impression that the sub is "off", when in fact it is technically "on", but there is simply no intended bass for the .1 channel in non DD, DTS mode.

Click to expand...

Thanks PENG,

Same here the receiver front display shows the Sub is on. I tried many different cd's, turntable, Sat receiver ...same results.
Like I mentionned in the first post, a friend of mine has the same combo (Denon 5900/3805) and he gets the sub to come on in scenario 2 above.

In the first post I mentionned also that the problem was in surround DPLII only, so we agree on that to.

BTW: I also tried setting the crossover Frequency to 250 Hz....same result


Seismo

Rschleicher, beating the dead horse or not, I thought we are saying more or less the same thing.

I did make sure that my sub's green light was on so I knew it was not automatically turned off due to a weak signal. I really don't know how Seismo's friend did it!

I only have the 3910, but I don't think the DVD player would make any different. Well Seismo, we are going to have to bite the bullet and set the center to small. BTW, we were on the same wavelength, I also tried XO=250 Hz, for the obvious reason............ Same result as yours, it didn't make any difference.

Seismo,
So you do understand how bass and/or LFE is routed based on the speaker and subwoofer mode settings and the only question is why you don't get much from the sub when playing a 2 channel CD using PLII?

The answer is simple and rshleicher and Peng already touched on a few reasons. I'll elaborate further, just for the fun of it.

A normal CD is not surround encoded in any way - there are no cues that tell the decoder what sounds go where. PLII takes any decorrelated (out of phase) info from the Left and Right and steers them to the surrounds. It takes in phase info from the L and R, sums them to mono, and sends them to the Center. The degree of bass and the amount of surround signal is therefore totally dependent on the recording itself - some will have lots of sound coming from the surrounds and many will not.

There will be little to no bass information that is out of phase with the rest of the sounds in the L and R channels, therefore little to nothing to send to the Ls and Rs. All of the bass is going to the Fronts because you have them set to Large. There will be some subwoofer activity when the Center is small, because the Center is derived from the in phase signals in the L and R, which include bass. If you want the subwoofer active for CD using PLII, set those Fronts to Small.

I know this is all technobabble, but that's the way it is designed to work and from your description, your receiver is doing exactly what it should do based on your setup.

Anonymous said:

I know this is all technobabble, but that's the way it is designed to work and from your description, your receiver is doing exactly what it should do based on your setup.

Click to expand...

We now all seem to agree that the sub is probably "on" as indicated by the display, but there is simply no intended bass going to the SurrL&R that could be re-routed to the sub, when playing CDs in PLII, IIx, or NEO6.

I still don't understand why Seismo's friend is not having the same experience. Perhaps different firmware version?? Not that it matters whether I will get that evasive bass or not, but part of the fun in owning a receiver is to be able to play with so many features, in between some serious music enjoyment.

Is there a good reason to set a basic center speaker to large?