LFE, subwoofers and interconnects explained - Page 23

Craig, Happy New year and thanks for getting back to me.

I have learned a bit more from this thread.

My #1 edict for Hometheater & Music: All 3 front speakers must be identical.

#2 Employ bass managment via the processor/ AV receiver


side note: I own klipsch LaScalas and they are great, it just that a third or center one would be out of the question. Therefore I am moving the lascalas to the "Man Cave" and adopting a new set of 3 front speakers and a pair of high output subwoofers.

When I am watching or listening by myself, I turn off the center channel. I do this because of my beautiful VMPS STIII towers. Try it, you might like it. I do.

After a good bit a research, 3 identical speakers up front are the most important factor in home theater. Tower, Monitors or even Tower w/ in line subs or Monitors with in-line subs.. what ever method gets you going, you must have 3 identical speakers for the three front channels.

Now that being said.. There are various levels of this set-up

1. The most afordable way is Monitors and a single sub. Directing all bass or summed bass to the subwoofer.
2. all of 1 but at an additional subwoofer
3. all of 1 but have 4 identical subwoofers
4. Towers, and one sub, crossed over around 40hz (crossed over via processor)
5. all of 4 but at an additional subwoofer (crossed over via processor)
6. all of 4 but have 4 identical subwoofers (crossed over via provessor)

i'll caveat this all and roughly quote Jim Theil " you take an normal speaker like the CS1.6 and rip out its crossover and put it in another speaker, that is what it's like with todays processors and AVRs and how they use bass managment, do you think you going to get an intergrated good sounding result?"

My logic says, "NO". Because crossovers are finely tuned for each speaker and you can just apply a one for all crossover. But I do use my AVR Bass Managment and thusly it's internal crossover with no issues ( as far as I know ) but still it leaves the wander of what it would be like with a separte crossover designed specifically for a speaker setup.. Like Thiel's own SCS4 and Smart Sub 1 hometheater.. could that be any better or is it applying logic to marketing versus real world postive results?

Ok guys,

I've replaced my interlink (analog) between my DMP-BD80 and my AVR-2105.
I bought an SPL meter and an calibration DVD.

When i calibrate my speakers and set the EXT-in boost on 15DB, I have to bring down the volume of the sub in my receiver a whopping 6DB!!
The article says that (as i stated before) when the speakers or one of them are set to smal a boost of 15db is needed. But that makes the boost completly
useless. Or am i completly wrong here

So, apply 10db of boost in your AVR instead of 15db. That's what I do with my Denon AVR.

I'm curious, tho. If you set speakers to large in the player, does the sub output increase by 5db?

Also, what's your calibration source?

You need to use a cal disc that has the test dignals in standard DD or DTS bitstreams. If your disc has that, great. If not, find a DVD with THX Optimizer. It will work perfectly for this procedure.

First a little housekeeping: Check the bass management settings in the Denon. Note how each speaker is set--large/small, and the crossover frequency. Duplicate those settings in the BD-80 speaker setup.

Also, make sure all post-processing and tone controls are turned off in the Denon.

1) Play the main channel tones via the coax connection. Write down the SPL for each channel. Do the same for the Subwoofer signal.

2) Play the same tones using the MCH analog input. Adjust the master volume on the first tone (L-ch) to achieve the same SPL as the L-ch from Step 1. This normalizes the analog and digitial paths. Write down all the SPLs for the 5.1 signals.

Your goal is to get the 5.1 readings in Step 2 to closely match Step 1. If not, apply gain trims to the channels as needed. This can be done in the Denon if it offers gain trims that only affect the EXT MCH input. If this is not possible, then adjust the BD-80.

Let us know if you are able to achieve a good match, and if so, they will sound the same regarding main/bass balance.

The disc has test signals in DD/DTS.
But why should i duplicfate the settings in the Denon?
The Denon can handle all the processing.

Not with analog. That's the whole issue. The AVR does not do the processing with analog and it must be done in the player.

Roger is recommending a method that produces the same SPL meter readings regardless of whether you are playing a track sent digitally to your receiver for processing or processed in the player for analog output.

Did you do the speaker set-ups in the player, including setting them to small? If not, that would explain why the sub is arriving approximately -10db instead of the expected -15db.

Ok I syncronized the settings in my receiver with the BD80.
The EXT-IN boost on 10DB
Then i played a test tone via COAX and calibrated al my speakers.
I did the Same with the EXT MCH input.

Ok i will try to discribe the problem (i'm from Holland)
After the calibration i put BB king Live At Montroux in the player.
I selected the HD Master Audio track and switched to the MCH output.

Every thing sounds fine, but here comes: when i put the receiver on Auto (coax, the receiver does the processing)
the is much more bass out of the front speakers, thats why i noticed the sub when i was in analog mode.

In other words it sounds as if my speakers are on small in the player. Why?
I checked the settings in the player and the speakers are defenetly on Large.

If your speakers are set to SMALL in the player, then you should set the EXT. IN SW boost to 15dB. But, if you do not have that option, or if you don't do that, you can still validly calibrate. You just find that extra 5dB elsewhere. What did you use to calibrate the multichannel analog connection? The AVR's multichannel input level trims or the player's output level trims (or both)?

Let me just confirm--are you using an SPL meter to measure these test signals?

I use the input levels of the avr, because there is no decent test signal on the player.


yes


I did set the EXT-in boost to 15db and then the bass from the front speakers is normal again.
But then the SUB is to boomy.
The sub is calibrated to 75DB

It does not matter if you use EXT gain of 10 or 15 dB, and it does not matter if the sub measures 75 dB. All that matters is that when the calibrations are finished, the gain differences across the 5 main speakers and the sub are the same for both the AVR decoded case as the player decoded case. The only acceptable difference being the master volume offset needed to normalize both cases.

This of course assumes the bass management is set the same in both decoders.

If the settings are matched, and the SPLs are matched, they will sound darned close. The only difference after that would be if you are applying some post-processing in the AVR for the coax delivered signals.

It does matter, because with the boost on 10db, there is little to no bass comming out of the front speakers (large)
When i set the boost on 15DB, everything is back to normal, excerpt the boomy bass comming out of the sub .

Sorry, but you appear to be missing the point. If you have properly calibrated for both digital through your receiver and analog through your player, the outputs of both will sound the same. The fact that they do not sound the same means the calibration is not complete.

I am confused, though, about the source of the test tones you are using for the calibration. In response to Roger, you said you are using a disc. Then, this exchange with sivadselim:



I don't understand what that means. The player's test tones are not being used, decent or otherwise. The tones are coming off the disc, yes?

It means that i use the AVr to adjust the volume levels with a test tone on a test disc.

I wil do another calibration (again) tonight.

I bought another BR disc and on that disc everything seems much better.
The bass levels are pretty equal.
I think that the panasonic is gulty to the bass problems.
When i switch to the Denon there is mutch more bass from the front speakers
With the Panasonic the amount of bass is much smaller.
Does the EXT-In boost setting on my Denon boost my speakers also? Because they are on Large.

Could you provide the bass management setting details for both the AVR and the and player? The Large/Small settings for each speaker group, and if small, what crossover frequency?

Also, what are the main L/R speaker used? Why do you have them set to large?

the limp man,

The point here is that you will have two completely independent and separate sets of settings for each of your two connections; digital vs. multichannel analog.

The AVR's bass management (LARGE vs. SMALL), time management (distance), and channel level trim settings will be applied to the digital connection and the digital connection, only.

For your multichannel analog connection, the player's bass and time management settings will be applied to the analog connection and the analog connection, only. For the individual channel channel level trims for the multichannel analog connection you can use either the player's level trim settings or you can use the AVR's multichannel analog input channel level trims. The AVR's multichannel analog input level trims are completely separate and independent from the AVR's channel level trims for the digital connection and will only be able to be adjusted when you have the multichannel analog inputs engaged.

Your AVR also has a setting which will provide the requisite boost to the subwoofer channel of the multichannel analog input cluster. You should set this to +10dB if your speaker sizes are set to LARGE within your player or +15dB if your speaker sizes are set to SMALL within your player.

Does your player allow you to configure the speaker sizes?

Yes it does. And with another Blu-Ray the above works perfect, no more boomy bass, but what i'm trying to tell you guys is that there is less bass coming out of the fronts when i'm playing with the EXTinputs.




Yes, i've set the FRONT L/R to Large. (crossover on 80hz)
the CENTER on Small
SURROUNDS on Small

My HT:

Denon AVR 2105
Panasonic DMP-BD80
Dali Concept 2 front
Dali Concept 1 back
Dali Concept Center
Rel Stampede SUB (this explains my Large setting on the fronts)

Well, are the speaker sizes and crossover set identically in both the player and the AVR? What are those settings? Are you absolutely certain that the digital and multichannel analog connection are calibrated identically. Because if not, making this comparison is not really possible. Even if the settings are seemingly identical, though, there can still be differences between the way that the two units handle bass management.



So, I presume you you have the REL connected, as REL recommends, via both a speaker-level and line-level connection? It may or may not be relevant to what you are observing (hearing), but I would strongly recommend you consider NOT wiring the REL that way and, instead, wiring it more conventionally.

I did try that a long time ago (its a pain to setup a rel correctly without a db meter) but ik like the sound with the speakers on large.

Well, if the player has ANY bass management settings it probably only has the choice of LARGE and SMALL speaker size settings. The crossover is in all likelihood fixed at some value such as 80Hz or 100Hz or 120Hz (or whatever). So, the only thing you can do is set the speaker size settings to those that are identical to what you are using with the AVR. In addition to the crossover being different, the slopes of the filters in the player and AVR may be different and that can definitely cause the two different connections, digital versus analog, to sound different.

But if you are setting your front speaker sizes to LARGE in both the player and AVR, the crossover will not be being applied to the front channels in either case so, provided you are comparing the two connections correctly, they shouldn't sound too different when conmparing 2-channel material. Realize though that when you listen to the digital connection, you are using the receiver to decode the material, and when you are listening to the multichannel analog connection, you are using the player to decode the material. So, it is possible (though doubtful) that you are hearing subtle differences between the two connections.





Well, ultimately you should use the method that sounds best to you. But in using the LARGE setting for your front channels you are not getting ANY of the benefits that are to be had by setting those channels to SMALL.

1.) Using the SMALL setting relieves the amplifiers from having to amplify the lowest frequencies, which are the hardest for an amplifier to amplify. Using a SMALL setting results in cleaner output over the range of frequencies that the amps ARE asked to amplify.

2.) Right now you are sending your front speakers, which are not LARGE speakers, a full-range signal. Using a SMALL setting relieves the speakers from having to try to reproduce the lowest frequencies, which are the hardest for the speaker to cleanly reproduce. Using the SMALL setting relieves the speaker of having to try and reproduce those lowest frequencies which provides for cleaner output over the range of frequencies that the speaker IS being asked to reproduce.

3.) A SMALL setting sends the lower frequencies to a speaker and amp (the subwoofer) that are specifically designed to amplify and reproduce those lowest frequencies. A subwoofer's placement is also usually a bit more flexible so that its placement can (when possible) be optimized for reproduction of those lowest frequencies. Granted, you are sending a full-range front channel signal to the sub's high-level inputs and applying the sub's low-pass atop that so you ARE sending low frequencies from the front channels to the subwoofer. Still, you ARE sending those same frequencies to the speakers, as well, and you are adjusting the sub to the speaker's low-end output or roll-off in your room. So, depending upon how much room gain you might have, you are probably not reproducing as much of the low frequency info that is present in the front channels at the sub as you would be with an appropriate SMALL setting and a crossover being applied to the front channels. Just curious. About what low-pass setting do you end up using on the subwoofer with your current setup?

So now you need to check the player menu. P37 of the manual says you can choose Large/Small for each speaker, and the crossover is fixed at 100 Hz. That will make only a small difference. Should be OK.

The time delays have to be entered as well. But even if you get them wrong, it will not affect the bass levels.


As you are using an SPL meter to calibrate the BD player, you've crossed that bridge already.

If you set the bass management to all = Small, and feed only the Sub output to the REL, not only will it be easy to set up, it will work better as sivadselim explained. Just set the crossover freq on the REL as high as it will go. Listen to the AVR while internally decoding audio, and adjust the REL gain until it blends well. Then proceed with the steps to match the player's signals using the test disc.

But thats not the way the Rel works, it doesn't sound as good.
Connecting the highlevel and setting the speakers to large works much better.

I guess I need an receiver that can decode the HD audio formats..

It will "work" either way.



Yes, it is very possible that this sounds better to you, which is fine. Integrating a sub properly with small bookshelf speakers, with the limitations of a crossover with fixed slopes, with no room treatments, with limited placement options, and no EQ capability, can be a real challenge. The 'special' REL connection method provides a bass management scheme that is very similar to an 'LFE+Main', 'LFE+', 'Plus', 'Double Bass', or '' setting.




If you mean so that you would be decoding, bass managing, and time managing the HD codecs identically, yes, that is what you would need. Still, with your fronts set to LARGE in both your player and AVR, you shouldn't be hearing such a huge difference, even though the crossover is slightly different between the two devices for your other channels. Your 'special' REL bass management scheme should be irrelevant. I suspect that you still have not calibrated the player's multichannel analog connection identically to the AVR.

It was the blu-ray disc. The audio was poor.
When i listend to anther blu-ray, it was much better.
As for the lack of bass in the fronts, i think its the panasonic

I get a nagging feeling that having two paths covering the same bass spectrum flowing together in the REL opens the door to complications if those two paths do not have identical timing to each other, for the internal vs external 5.1 decoding. In one case they will sum more coherently than the other.

It's all very iffy because while the mains and sub outputs ought to carry different signals, there is the real possibility the carry similar signals, and sometimes share the same signals.


All the more critical when bass is being mixed this way. Comparing the distance/time/level settings of the two bass management setups would be required to verify.

Switching to a conventional bass management method would eliminate that mixing/timing uncertainty altogether. What would it hurt to flip a few switches and disconnect the high-level input to the REL, and see what can be achieved with a fresh pass at bass management and tuning? If it didn't help, the original settings can all be restored.

Well, the potential for the timing of the player's decoding and the AVR's to be different is there, regardless, I suppose. I don't really think this is the source of whatever it is that he is hearing. I still suspect that he is not really comparing the two connections as equivalently as possible. That's not entirely clear based upon what he has posted.

I agree that there is going to be considerable overlap between what is encoded in the main channels and the LFE channel. Essentially he has a setup that would be similar to having two identical subs, one dedicated to supplementing the low-end of 2 small bookshelf speakers set to LARGE and the other dedicated solely to the LFE channel (and rerouted bass from SMALL channels). The difference being that, with his setup, at least the reproduction of those two (or three) separate 'basses' is from the same unit. With the other setup (two separate subs) at least the relative phasing of the two separate subs could be adjusted to affect the time coherency of that overlapping material.



He might be able to get the two connections to sound more similar if he did this, but he still thinks that the REL connection scheme sounds best to him. And it probably does. Can't argue with someone's preference. So, he has compared the results of connecting the sub both ways at least as far as it is related to a his digital connection and AVR's bass management settings.


REL has always been extremely adamant about their connection scheme being the right way to do things with their particular subs.

but the sound is awesome

Ok, can someone please tell me if I have to add the +10db on my receiver?

AVR = Integra 7.6 (HDMI 1.1)
BD = Pioneer BDP 51
Speakers = Energy Reference Connoisseurs 50's
Sub = Velodyne SPLR1000
All connected with HDMI 1.3 cables

Ok here are my settings in my AVR!

Speaker Config
------------------------
Subwoofer :Yes
Front L & R:80Hz(THX)
Center :80Hz(THX)
Surround :80Hz(THX)
SurrBack : None
LPF of LFE: 80Hz(THX) What the heck is this setting
h.Subwoofer Mode
:-------------

What I don't understand is the part of the manual on the LFE. It seems to say that I can't add a 10db increase to the LFE channel.

LFE Level Setting

"With this setting, you can set the level of the LFE (Low Frequency Effects) channel for Dolby Digital, DTS, MCH PCM (HDMI IN), and MCH Ana (multichannel DVD input). The level can be set to -∞, -20 dB, -10 dB,or 0 dB (default).
If you find that the low-frequency effects are too loud when using one of these sources, set the level to -20 dB or -∞ dB."

If 0 db is the default, then I can't use -10 dB, or -20 dB, or -∞ because they reduce the volume of the LFE!!! The AVR also allows me to apply these numbers to DD, DTS, and Multichannel PCM ( which BTW is how the BD player feeds my AVR via the HDMI 1.1) independently of one another.

Any help would be appreciated!!

Paul