# Bass Effects on Downmixing DD to Stereo and Spectrum Labs information



## Ilkka

Steve Callas started a similar thread over at AVS. Since I have some issues with AVS  , I decided to start my own thread here. Here's a link to AVS thread: http://www.avsforum.com/avs-vb/showthread.php?t=723258&page=1&pp=30



Mark Seaton on AVS said:


> When a DD soundtrack is downmixed to stereo or DPL, the LFE channel is thrown away. If you want to listen to DVD soundtracks with a powerful set of stereo main speakers you want to make sure you are in a DD mode and have the system set to yes or no to all of the appropriate speakers. While it should be obvious, if you don't have a center or a sub, be sure that you select that in the setup.


This is correct when strictly talking about downmixing. But almost every receiver/pre/pro has a some kind of bass management, which allows us to redirect the LFE channel into main channels (L&R) if there are only for example two speakers in the system. There are a few receivers that don't handle it perfectly, they usually attenuate the level of the LFE by 6 dB (for example some Marantz units). Disabling either the center or the surrounds when playing DD tracks will cause some problems like loss of dynamics and SPL. Check a few posts down for more information. 

This is not the case with DVD players though. There are only a few DVD players which can redirect the LFE channel into main channels (for example Sony DVP-NS900). And of course then the player has to be connected either via digital output (coax/fibre) or via multichannel analog outputs.

If you connect a DVD player via analog stereo outputs (or via SCART to a TV), the LFE channel WILL get thrown away. Dolby specs don't allow LFE to be downmixed into analog stereo outputs.

AC3filter used with Spectrum Labs program does handle the LFE redirection perfectly. Nothing will be left out and no attenuation will be made. Though it requires that the program has correct settings in it. I've been doing these waterfall charts for a while now and I thought I had the correct settings, but today I started explore this matter a little bit more, and found out that the LFE channel level has been +6 dB in all the charts I've done (and in other people's charts too, since most of them were using my settings). Let me explain why.

The AC3filter uses a matrix chart to control the level of individual channels. I've been using the "auto matrix" option all the time, but it doesn't seem to work properly after all. The program correctly downmixes 5.1 channels into 2 channels, but it puts the LFE into both channels (L and R). This shouldn't be done since Spectrum Labs program adds both channels together for a mono signal, which it then monitors. Since the AC3 filter downmixes the LFE into both channels, we get this +6 dB error. But luckily there is an easy solution.

Turn off the "auto matrix". Place a zero in LFE/R cell. LFE/L cell must read 1. Now the LFE channel will be downmixed only to left channel and the relative level compared to redired bass will be correct.










I took some new charts from the WOWT with these new settings, though the results are still pretty much identical with the old ones, since the LFE channel hasn't got much material in it. As you can see, most of the bass is actually redirected bass, not LFE. These charts show the full lightning scene from the first strike to the last one. DTS track was used.


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## Ilkka

Ed Mullen on AVS said:


> A great example is the plane barrel roll (about 4 continuous seconds at ~ 30 Hz) during the crash scene in the Flight Of The Phoenix. That bassy special effect is exclusive to the LFE channel.


Here are the charts which prove that Ed is telling the truth.


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## eddthompson

great stuff, perhaps this explains some of the issues chrissbee was having.

edd


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## Exocer

Hey Ilkka,
I ran a few tests to measure the differences in LFE output when using only 2.1 channels playing a DD 5.1 track. The mains were disconnected for both tests. 

I watched the DD 5.1 track with only L/R and LFE enabled for the first test. At -15db on the AVR my SPL meter measured 102db max spl.

I then watched the same scene in DD 5.1 enabling all 5 channels at -15db on the AVR. Max SPL came in at 105-106 db.


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## Ilkka

J_Palmer_Cass on AVS said:


> If you do not use a DD 5.1 DVD with a full speaker compliment , then DRC is used regardless of the DRC setting in your receiver.
> 
> The DRC value is determined by a specific DRC downmix value selected by the mixer in the DVD encoding process. It is not user adjustable, and it overrides the DRC setting that you have selected in your receiver.
> 
> For example, my test of Master and Commander told me that for M & C DRC is set to MAX if I set my center speaker to OFF. LFE is still there, but DRC squashes everything down. Low bass, low sound effects, and the like.


First I didn't believe this could be true, but after I run some tests of my own (NAD T743 AV-receiver), I must admit that he's being right. It seems that the Dolby decoder has a will of its own, it will set on the DRC if one doesn't have all five speakers enabled. Also downmixing to stereo seems to have an exact effect. The amount of DRC probably varies between soundtracks.

I measured a few scenes with a professional SPL meter with four different configurations: DD 5.1, Downmixed 5.1 'stereo', DD 4.1 (center disabled) and Downmixed 4.1 'stereo' (center disabled). In reality I don't have a center speaker.

DD 5.1 always gave the highest SPL result, the other three were identical, but always much lower level.

FOTP - 'barrel roll': ~10 dB difference 
M&C - 'first round': ~18 dB difference
WOTW - 'lightnings': ~9 dB difference

Those are pretty big differences, don't you think?! :raped: No wonder I have always preferred DTS tracks over DD (since normally my center IS disabled). DTS doesn't contain any DRC information!

*If you don't have all five (5) speakers enabled, you will lose great amount of dynamics and max SPL when playing Dolby Digital soundtracks.*


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## eddthompson

again, i belive chrissbee uses no centre, and has the .1 turned off, and hees been suffering dynamic range issues etc, a shame since he has an ib.

edd


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## Ilkka

eddthompson said:


> again, i belive chrissbee uses no centre, and has the .1 turned off, and hees been suffering dynamic range issues etc, a shame since he has an ib.
> 
> edd


Yes, disabling center will cause dynamic range issues with DD tracks. Disabling subwoofer doesn't seem to have this same effect though.


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## SteveCallas

*Finally* I can get this page to load at home. Something about our internet servers at work didn't want to let me open this webpage for the past several hours. Anyway, that's neither here nor there.



Ilkka said:


> First I didn't believe this could be true, but after I run some tests of my own (NAD T743 AV-receiver), I must admit that he's being right. It seems that the Dolby decoder has a will of its own, it will set on the DRC if one doesn't have all five speakers enabled. Also downmixing to stereo seems to have an exact effect. The amount of DRC probably varies between soundtracks.
> 
> I measured a few scenes with a professional SPL meter with four different configurations: DD 5.1, Downmixed 5.1 'stereo', DD 4.1 (center disabled) and Downmixed 4.1 'stereo' (center disabled). In reality I don't have a center speaker.
> 
> DD 5.1 always gave the highest SPL result, the other three were identical, but always much lower level.
> 
> FOTP - 'barrel roll': ~10 dB difference
> M&C - 'first round': ~18 dB difference
> WOTW - 'lightnings': ~9 dB difference
> 
> Those are pretty big differences, don't you think?! No wonder I have always preferred DTS tracks over DD (since normally my center IS disabled). DTS doesn't contain any DRC information!
> 
> If you don't have all five (5) speakers enabled, you will lose great amount of dynamics and max SPL when playing Dolby Digital soundtracks.


What, did you expect my "true story" was really a lie? :T Thanks for putting it to the test with measurements though - would you mind if I posted just this section: 

FOTP - 'barrel roll': ~10 dB difference 
M&C - 'first round': ~18 dB difference
WOTW - 'lightnings': ~9 dB difference

at AVS? More people need to be aware of this. Sounds like there is a guy on this forum with an IB that is making the same mistake. I know Jon was really happy after we discovered the problem....his 100 year old house wasn't too thrilled though :surrender:


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## Exocer

I am wondering where a 3.1 channel system falls in the grid of things...Would it still pose as much of an SQ/SPL loss as downmixing to stereo? Its too late for me to run those tests here but i'll try tomorrow if there isn't already a definite answer.


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## Ilkka

Exocer said:


> I am wondering where a 3.1 channel system falls in the grid of things...Would it still pose as much of an SQ/SPL loss as downmixing to stereo? Its too late for me to run those tests here but i'll try tomorrow if there isn't already a definite answer.


It did the testing also with this configuration and the result was exactly the same as when you disable the center. 4.1, 3.1, 2.1, 4.0, 3.0, 2.0 - same SPL loss compared to 5.1 or 5.0.



J_Palmer_Cass on AVS said:


> Downmixing in the receiver activates the DD DRC downmix value (which is different for different DVD's). The DRC value selected by you via the receiver is ignored when you downmix.
> 
> Downmixing means disabling the center, or the surrounds, or both together. Anything except 5.1 or 5.0 is considered downmixing.
> 
> Downmixing does not mean selecting the subwoofer as off or on.
> 
> Downmixing in a DVD player is different again (LFE is dropped), but the DD DRC downmix value is used in the DVD player also.
> 
> The reason this DRC downmix value exists is that when you downmix you can overload the DAC's in the receiver if this downmix DRC is not applied. A DTS DVD DECODER has a similar downmix overload feature (compression) as I recall.
> 
> Remember that these DECODERS do things that are not obvious!!!


Just like he says, only the DTS part is incorrect. I tested it too and DTS doesn't behave the same. There is no loss if you disable the center or surrounds. DTS doesn't carry any DRC information. Surprisingly DD 5.1 was only around 2 dB behind DTS at the same MV setting (Master and Commander).

So do remember that this happens only when playing DD tracks, DTS doesn't have this problem.


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## Ilkka

SteveCallas said:


> *Finally* I can get this page to load at home. Something about our internet servers at work didn't want to let me open this webpage for the past several hours. Anyway, that's neither here nor there.
> 
> What, did you expect my "true story" was really a lie? :T Thanks for putting it to the test with measurements though - would you mind if I posted just this section:
> 
> FOTP - 'barrel roll': ~10 dB difference
> M&C - 'first round': ~18 dB difference
> WOTW - 'lightnings': ~9 dB difference
> 
> at AVS? More people need to be aware of this. Sounds like there is a guy on this forum with an IB that is making the same mistake. I know Jon was really happy after we discovered the problem....his 100 year old house wasn't too thrilled though :surrender:


No, I didn't think you were lying, I just thought there may have been some other reason. You can post the numbers, but don't post the whole thing. AVS doesn't deserve it.


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## SteveCallas

Lol, ok, no worries, I won't post any, as this thread is linked to over there. As bad as AVS is, that other place with AV in the name is even worse  Of course the Shack beats them all anyway...


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## Chrisbee

Bwaaah! :hissyfit: 

Thanks for this timely thread Ilkka. 

I'm using a NAD T533 DVDP to feed my Naim stereo pre-power + EP2500 pro-amp driving the IB.

I'm using an active crossover at 80Hz to split between front speakers and the IB.

I use the DVDP's multichannel analogue connections to an old Yamaha DSP E800 for my rear speakers only.

The Yamaha SQ is not good enough to use as the surround processor in my system. It displays all the symptoms of most of the affordable surround kit that I have heard so far. (Poor dynamics, poor dialogue clarity, scratchy and tinny ambient effects with emphasis on the HF) 

In discussion with NAD they warned me that the T533 is not a surround processor.

I still believe the T533 can redirect bass from Small Rear speaker settings to Large Fronts. 

I confirmed this using "The Calibrator" test DVD on (spoken voice) channel ID. The subwoofer pink noise test produced no redirection to the Mains.

Centre was redirected to L&R Mains when Centre set to None. Rears sounded out of phase coming from the Mains but the signal was redirected to Mains when rears were set to Small and muted at the rear.

My Centre is normally set to None in the DVDP. LFE doesn't exist since I'm only using the Front Mains = Large signal. So LFE must be dumped by the DVD as you suggest.

I tried my SVS on the centre channel and found loads of deep bass in there when set to Large. But I really don't want the SVS running with the IB and certainly not as a centre speaker when I get such excellent results from my main speakers. 

How do I keep my present SQ while getting the benefit of my missing LFE? (and any other non-redirected bass) :scratch: 

I don't get any sound out of my DVDP from the analogue sockets if I select the optional DTS instead of DD5.1 in a film menu. Without an AV receiver I can't use digital connections.


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## SteveCallas

Buy a third main to use as your center speaker. I run three vertical towers myself.

Please don't anyone take this the wrong way, I honestly mean no offense by it, but did you guys never question the bass or dynamics you were getting in movies when compared to the impressions or graphs other members were posting? As I've stated, not only do you lose bass, but you lose top end clarity as well due to clipped peaks. I remember Jon being quite disappointed over the phone after watching some movie scenes in 2.1 after all the hoopla people had made about subwoofers and certain bass scenes - and even the hoopla I made about the LLT design :huh:


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## Guest

Ilkka said:


> It did the testing also with this configuration and the result was exactly the same as when you disable the center. 4.1, 3.1, 2.1, 4.0, 3.0, 2.0 - same SPL loss compared to 5.1 or 5.0.
> 
> 
> Just like he says, only the DTS part is incorrect. I tested it too and DTS doesn't behave the same. There is no loss if you disable the center or surrounds. DTS doesn't carry any DRC information. Surprisingly DD 5.1 was only around 2 dB behind DTS at the same MV setting (Master and Commander).
> 
> So do remember that this happens only when playing DD tracks, DTS doesn't have this problem.





Actually, DTS is different than DD in that DD uses DIALNORM, and DTS does not do so. DIALNORM reduces volume by an amount that varies from DVD to DVD. There is no volume reduction when the value of DIALNORM is -31.

If a DD DVD has a DIALNORM value of -31 (like Air Force 1), then DD and DTS will playback at the same volume level.

The Master and Commander DD DVD uses a DIALNORM value of -27, so volume is reduced by 4 dB (-31 -(-27) = -4) as compared with the DTS version. DTS and DD sound just about the same if you set the DTS version 4 dB lower than the DD version. 

The War of the Worlds DD DVD uses a DIALNORM value of -23, so volume is reduced by 8 dB (-31 -(-23) = -8) as compared with the DTS version. DTS and DD sound just about the same if you set the DTS version 8 dB lower than the DD version. 


My receiver reads out the DIALNORM value that is ENCODED in the DVD, so I can read the DIALNORM value directly on my receiver. Does anyone else have this feature?


As far as downmixing DTS is concerned, I tried downmixing M & C DTS last night. If you downmix the DTS version of M & C, it does not sound the same as the 5.1 version. It sounds like a bit of overload compression is used, but not anything like the drastic DD DRC. Perhaps it is just the electronic downmixing of signals that changes the sound.


Anyhow, everyone should use a full 5.0 or 5.1 system (even with ****** speakers). Some DVD's just sound BAD when you downmix, DD versions in particular!


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## Ayreonaut

I don't have a center channel right now. 
My receiver is the Denon AVR-1905. 
How should I test to see if it is compressing DD dynamics with "Center Sp." set to "None"?

BTW, this is a real problem that Dolby needs to fix *immediately.*


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## Ayreonaut

I found this in the user manual for the Dolby Model DP564 Multichannel Audio Decoder



> *Compression*
> The Compression buttons can apply the dynamic range control profiles available to consumers when decoding Dolby Digital audio. Only one of these modes is active at a time; to disable compression, press the active button.
> 
> RF applies the strongest profile available, equivalent to an RF connection to a TV set or small PC speakers. Line applies what appears on some consumer decoders as “light” compression; this is usually the default setting in DVD players and set-top boxes. Custom allows scaling of the Line profile. The factory setting for Custom is 0 percent. At that setting, selecting Custom turns off dynamic range compression. To access the display screen to adjust the percentage setting for custom scaling, hold down Custom for two seconds.
> 
> * Note: When downmixing, the DP564 automatically applies compression at peak moments to prevent potential signal overload from combining multiple channels, regardless of whether a compression mode is selected.*


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## SteveCallas

J_Palmer said:


> My receiver reads out the DIALNORM value that is ENCODED in the DVD, so I can read the DIALNORM value directly on my receiver. Does anyone else have this feature?


Yes, my Yamaha HTR 5890 does the same thing at the start of a movie. I always get a little perturbed when I see that **** "Dial Norm. -4db" pop up on some movies :R In fact, it even comes up on a DD intro demo disc I have, you know, the ones with the DD helicopter, train, canyon, pyramid, etc.



Ayreonaut said:


> How should I test to see if it is compressing DD dynamics with "Center Sp." set to "None"?


Play a bassy movie scene with your setup as it is now. Then tell your receiver you DO have a center channel and surrounds (even if you don't have anything connected) and play the scene again. You should notice more bass. If you really did have a center channel connected, you'd notice more clarity too. I never realized how many people weren't using center channels


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## brucek

> I never realized how many people weren't using center channels


Neither did I.

Why aren't they? Is it financial or some preference for phantom, etc ?

brucek


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## eddthompson

people have the notion that stereo equipment is better :neener: 


edd


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## Ayreonaut

First, I think there's difference between Dialnorm and DRC. 
Dialnorm raises or loweres the whole volume level; that can be fixed with a tweak of the volume knob. 
DRC is not linear in that it compresses the dynamic peaks; that can't be fixed with the volume knob.

I don't use a center because I didn't think I needed one. I've used one in the past and thought it gained me nothing. I have a 32"CRT and my mains are pretty close, so there's no hole in the center and dialog seems pretty anchored to the screen.

I'll have to investigate this compression thing though...


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## SteveCallas

Ayreonaut said:


> First, I think there's difference between Dialnorm and DRC.
> Dialnorm raises or loweres the whole volume level; that can be fixed with a tweak of the volume knob.
> DRC is not linear in that it compresses the dynamic peaks; that can't be fixed with the volume knob.


Correct, J_Palmer brought up Dialnorm to explain the differences in output level between DD and DTS - the DRC of DD without a center channel or surrounds is a different issue altogether. 



> I don't use a center because I didn't think I needed one. I've used one in the past and thought it gained me nothing. I have a 32"CRT and my mains are pretty close, so there's no hole in the center and dialog seems pretty anchored to the screen.


Hmm, can you go wider with your mains? I find that trying to stay close to an equilateral triangle between the mains and seating position gives the best soundstage and panning.


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## brucek

> I have a 32"CRT and my mains are pretty close, so there's no hole in the center and dialog seems pretty anchored to the screen.


Yeah, that makes sense, although if the physical situation allowed you to separate those mains and add a center, the soundstage would be quite a bit better.

brucek


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## Ayreonaut

SteveCallas said:


> Hmm, can you go wider with your mains? I find that trying to stay close to an equilateral triangle between the mains and seating position gives the best soundstage and panning.


I wish, but I'm wedged into a corner. Good ol' domestic considerations.


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## Chrisbee

With my speakers 6 feet apart I get all the steering I need from around 9 feet away. 

(A central chimney and stairwell force me to listen across one end of my 30 foot room)

The tip to try setting the centre to small when none is present sounds good. :T

I shall try and confirm this works later when I'm setting up for a film.


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## Ayreonaut

Chrisbee said:


> The tip to try setting the centre to small when none is present sounds good.


Wouldn't that just redirect the CC bass, but toss away all the rest of the CC info?


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## brucek

> Wouldn't that just redirect the CC bass, but toss away all the rest of the CC info?


Yeah, makes no sense to me...........


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## eddthompson

i think it was merely to test the spl at a set volume, centre on, and centre off, to find out if the drc is affecting the spl.

ie, at -10 on the reciver, centre to on (even if theres no centre) measure the spl of your fave scene, then do the same with the centre set too off. The theory goes that with the centre off the drc will lower the total spl. which is bad, of course this doesnt apply to dts.

edd

edit: spl=sound pressure level drc=dynamic range compression, too manuy accronyms


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## Chrisbee

I'm afraid this idea crashed and burned via my DVDP (no receiver) based system.

_No dialogue!_ 

Pardon?

I said; "*No dialogue*".


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## SteveCallas

Yeah, you won't be able to use it as a permanent method, but as a test, you should be able to notice the difference in bass output with the center and surrounds "on".


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## Chrisbee

But isn't it rather academic if I can't hear the dialogue? 

It's rather like saying you can save fuel by not starting your car.


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## eddthompson

no its like saying alter your system to have a centre, or only listen to dts track, or suufffeeerrr terrible dynamics. :neener: 

edd


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## Chrisbee

DTS deosn't work on DD only films. :neener:


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## eddthompson

exactly, suffeerrrrrrrrrr :bigsmile:

Back of amp im assuming this is the back of your e800, if so have you tried using it purely as a 5.0 preamp? ignoring any of it processing and just using the ext decoder in from your dvd player? can you not run a centre much like you run you rears? after all sound quality may not be hugely important on the centre compared to the extra quality gained from the increase in dynamic range.

edd


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## Chrisbee

My dynamics are still better than your dynamics! :neener:


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## eddthompson

if the dynamics are crushed on the out put, i could be realy screwing up the sound, thats all im worried about, especialy as you have such an awsome sub, i recall u saying lotr was an amazing experience, possibly because you used the DTS track? have you compared it to the DD track, if there is a huge difference in quality, sub output, dynamics etc, then it sounds like this sneaky drc stuff is causeing you grief. i just think it seems to be the issue we had a discussion about not long ago, i wasnt being nasty, just slightly cheeky :bigsmile: 

edd


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## Chrisbee

No worries, Edd!  I was just winding you up too. 

I haven't tried DTS because I get no sound when I try and play a DVD in DTS mode.

If I wasn't so lazy I'd have a dig round in the DVDP instructions to find out why. Probably some obscure choice in the menues.

I'm still trying to locate a matching Centre speaker but the old Mission 75C Freedoms don't come up very often on the used market. 
Getting a used one sent over from England would easily double the secondhand sales price in postage.

I'm also looking at mid-price AV Receivers. Thought I might get a matching NAD to go with my DVDP. Only because I like the colour.


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## eddthompson

Thats ok then, thought id insulted you, im dyslexic and my posts often are misunderstood, due to my inability with writen language.

If you find one in england id be happy to foward it to you, although i bet shipping would still be prohibative.


edd


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## Chrisbee

Thanks for the kind offer Edd. :T 

I'm still hoping I can find one over here before resorting to Parcelforce.


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## eddthompson

:hissyfit: parcel force :crying: all other avenues must be looked into :bigsmile: 



edd

edit: at the cost of flights ill fly it over and visit lovely finland (£150)  lol, well, i think your in finland, my memeory fails me, or was it denmark, i get confused, i have to many multi nations aquaintenses.


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## Chrisbee

eddthompson said:


> :hissyfit: parcel force :crying: all other avenues must be looked into :bigsmile:


I know! I know! 

When I think of the times the carriage has exceeded the cost of the goods it makes me want to cry. It might be cheaper to fly over except for the time it all takes going both ways.


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## eddthompson

lol, i think you missed my edit!!

edd


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## SteveCallas

Chrisbee, I have done blind testing of processing only going from a really entry level receiver to a dedicated pre/pro renowned for it's sound quality. When you feed them all to the same amp, so the receivers are only being used as pre/pros, they all sounded exactly the same. See here if you are interested. So if you have some beefy, discrete amplification, you really wouldn't be giving up any sound quality, and you'd be gaining a lot of capability.

As for the center channel, at the moment, it's like a hole in your sailboat while you're out on the sea.....plug it up now - you can do the more elegant repair later (add another Mission 755C). All joking aside, you are currently getting a pretty watered down experience  Plug that hole!


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## Chrisbee

Steve

I read that blind review a while ago but never realised you were involved. No wonder they don't like you on AVS. 

Since I don't need most of the amplification in an AV receiver, don't need HD and I'm not stretching to a processor the task merely becomes one of selection. What you are basically saying is that if I like the look of the fascia then that's about it? But that's what we've all beeen doing for years, isn't it! :devil:


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## Ayreonaut

Dolby Digital Guidelines
This document contains guidelines from several Dolby Laboratories publications



> In addition to the DRC profile, metadata can limit signal peaks to prevent clipping during downmixing. This metadata, known as overload protection, is inserted by the encoder only if necessary. For example, consider a 5.1-channel program with signals at digital full scale on all channels being played through a stereo, downmixed linelevel output. Without some form of attenuation or limiting, the output signal would obviously clip. Correct setting of the dialogue level and DRC profiles normally prevents clipping and unnecessary application of automatic overload protection.


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## Ayreonaut

From "All About Audio Metadata"



> *Downmixing
> 
> * Downmixing is a feature within Dolby Digital that allows a multichannel program to be reproduced by fewer speaker channels. Simply put, downmixing allows consumers to enjoy a digital television broadcast without requiring a complete 5.1-channel home theater setup.
> 
> As with stereo mixing, where the mix is monitored in mono on occasion to maintain compatibility, multichannel audio mixing requires the engineer to reference the mix with fewer speaker channels to assure compatibility for downmixing situations. In this way, metadata allows Dolby Digital to be an “equal opportunity technology” so that every consumer who receives a Dolby Digital data stream will be able to enjoy the best audio reproduction possible irrespective of the number of channels in their playback system.
> 
> Set-top boxes for terrestrial, cable, or satellite digital television will typically offer a mono signal on the RF/Antenna output, a line-level analog stereo signal, and a optical or coaxial digital output to convey the Dolby Digital stream to a decoder.
> 
> The analog stereo signals that are output from these units are most often internally downmixed from the original Dolby Digital multichannel audio program to ensure compatibility with nondigital home theater systems. This analog output can be one of two different types of stereo signals. One type is a stereo-compatible Lt/Rt (Left total/Right total) downmix suitable for Dolby Surround Pro Logic decoding. The other type is a simple stereo Lo/Ro (Left only/Right only) downmix suitable for playback on a stereo hi-fi or via headphones. That same signal is used for deriving the mono signal for use on the RF/Antenna output.
> 
> Certain metadata parameters allow the engineer to select which stereo analog signal is preferred as the default signal at these output connections and how that stereo downmix is constructed. In addition, within the metadata parameter library there are separate parameters for the adjustment of the Lo/Ro and Lt/Rt downmix conditions.
> 
> During downmixing, the adjustment of dynamic range control parameters is limited, and this is no different when using the signals present at the stereo or RF/Antenna outputs. The mono signal present at the RF/Antenna output of a set-top box will be applied with maximum DRC (RF Mode Profile) at all times to help prevent RF overmodulation. Certain metadata parameters assist in achieving an appropriate downmix, helping to ensure that the intention of the engineer/content producer will translate across these environments. Specifically, metadata provides control over how certain speaker channels are “folded” into the resulting downmix.
> 
> While the engineer must optimize the multichannel mix for reproduction in an ideal listening environment, it is important to preview the mix in downmixing conditions to ensure compatibility with different playback systems when selecting the downmixing metadata parameters. These previews can be achieved in real time using the DP570 Multichannel Audio Tool.


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## SteveCallas

> No wonder they don't like you on AVS


:devil: Yep, the eccentric types over there despise me. The straight shooter types, though small in number, appreciate it.



> Since I don't need most of the amplification in an AV receiver, don't need HD and I'm not stretching to a processor the task merely becomes one of selection. What you are basically saying is that if I like the look of the fascia then that's about it? But that's what we've all beeen doing for years, isn't it


At the end of our test, I basically thought the same thing. After having a few new receivers in my system since then though, I realized there is more to consider. First, obviously, make sure it has all the inputs/outputs you need and then a few more "just in case". 

Second, make sure it has a relatively "clean" power supply and output stage. By that I mean that some receivers induce a hiss in the analog outputs that is not attributed to ground loops or cables, it's just inherent in the receiver. The HK 635 I had was dead silent. The Pioneer 1015 I had was dirty. The Yamaha 5890 that I am using now is almost dead silent - if you stick your ear to within 1' of the tweeter, you can hear a slight hiss, beyond that, it's silent. I guess this could also be considered build quality.

Third, I feel remote layout and feature navigation is WAY underrated. If you have to actually stop, search the remote, guess and check a few buttons, and hope you can find your way in the receiver to do what you want to do, you will grow very frustrated VERY quickly. Especially when you are starting a movie and the lights are off :hissyfit: 

Fourth, what the unit's display display's, how large it displays it, and where it displays it. If you can't quickly and easily tell what surround mode you are in, what speakers are activated, what your master volume level is, and what input you are on in a glance, again, it gets really frustrating.

Lastly, unit quirks. This one is tough because you will need the unit in your system for a couple days to find any - but they ALL have them. They are unique to each brand, and they come in varying degrees of annoyance, but they all got them. The HK chopped off the first 1 second of audio when changing tracks because it has a feature to mute output from a digital audio connection when the signal is dropped or has no output. When you change a track on a disc player, for a brief second, there is a pulse or something in the digital connection that the HK interprets as needing to mute. Very annoying. The Pioneer had a non shielded power supply that would create electromagnetic intereference - meaning when placed on a shelf driectly above my old CRT TV, I would get green and purple splotches right below the left hand side of the receiver, right where the power supply was :rant: My Yamaha defaults to always turning on with Zone 2 and Zone 3 lit up on a small area on the display, and I have to press a button twice to get rid of it. I think when those zones are on, you could potentially be getting less power to the main 7 speakers, and though I only use it to power my four surrounds and center, I'm ****. I don't find this too bad though, as pressing the button twice on the remote takes me about 1 second.

Hope that helps. You didn't ask for one, but if I had to give a recommendation, based on the units I have used, I'd definitely go with a Yamaha based on the categories I mentioned above.


----------



## eddthompson

yep, ive had sever recieveres/processors, nothing in them realy, the only one that was better was the ead, and that i think was due to its build quality, superb releys, super silent power supply, always made anything sound so clean and dynamic. dunno whether its super duper reclocking circuitry did anything.

always been a fan of pioneers, denons are well build, yamahas again ive owned and liked.

My new denon certainly isnt any worse, it sounds a bit different, better or worse no, just different, on a blind test i doubt i could tell the 2 apart with any accuracy. bit i got the denon as its the mother ship of all things socketry.

i love the arguements on avs or avforums, you try and tell some one processors are about the same (and power amps, even cd players to a point, if its wildly different, its fiddling with the sound in my book) and you get lambasted with stuff like, noooo meridians/brystons/lexicon/arcam just have that something special (snake oil and fairy dust). ill never tire of people claiming arcam gear is better with music because its arcam.

not that i wouldnt buy such equipment, its very well made :bigsmile: but would it sound better than i have now? doubt it.

dont even get nme started on cable, especialy power cables costing $$$$.

edd


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## Chrisbee

Thanks. But now where do I start? 

You like them all but they all have their own foibles? 

Pinning the tail on a donkey suddenly seems easy. 

I still like the battleship grey one.


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## eddthompson

well, ive owned a yamaha, sony, pioneer, denon, recivers and the ead processor, ive demoed and played with others. the only one i had problems with was the sony, it had a dodgy display and the volume knob fell off, it and the yamaha however are still going strong in friends homes 5 years on. (most of my stuff ends up in friends houses)

the pioneer had a nice remote :R and any form of auto calibration is rubbish, well in my experience.

so far the most signifigant upgrade i made was the power amps, followed by the bfd. My speakers were origanly £3000 ($5000) but i got them on ebay for £500, i dont think ill ever change them. 

i tend to put the display first.

The best place to start is ebay if you ask me, i buy nearly everything used :bigsmile: nad are also well priced, just tend to be quite basic. as long as it has pre outs you can still use your naim power amps and behringer crossover. 5.1 input is also very handy.

edd


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## Chrisbee

Thanks Edd. I'll take a tour round the dealers to see what appeals.


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## bossobass

> The HK chopped off the first 1 second of audio when changing tracks because it has a feature to mute output from a digital audio connection when the signal is dropped or has no output.


This is why it appeared to be 'dead silent'. Mute function.

Bosso


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## Sonnie

SteveCallas said:


> I don't find this too bad though, as pressing the button twice on the remote takes me about 1 second.


I figured you for a Home Theater Master, Pronto or Harmony.... one of the learning ones anyway. A macro at turn on solves pressing that button twice. Something tells me you already know this. :nerd:


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## SteveCallas

bosso said:


> This is why it appeared to be 'dead silent'. Mute function


Are you referring to the analog outputs being dead silent?



Sonnie said:


> I figured you for a Home Theater Master, Pronto or Harmony.... one of the learning ones anyway


Nah, I actually like having seperate remotes - no way am I going to spend the time to program all the minute little functions. Also, if I want to keep testing a track on a disc, I can easily adjust receiver settings and work the dvd player with two remotes whereas with a universal I would have to get out of ones functions and go into the other. The only functions I may want to combine are those of the tv and HD cable box, and the universal remote that came with the HD cable box should be able to do that with ease.


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## bossobass

SteveCallas said:


> Are you referring to the analog outputs being dead silent?
> 
> 
> Nah, I actually like having seperate remotes - no way am I going to spend the time to program all the minute little functions. Also, if I want to keep testing a track on a disc, I can easily adjust receiver settings and work the dvd player with two remotes whereas with a universal I would have to get out of ones functions and go into the other. The only functions I may want to combine are those of the tv and HD cable box, and the universal remote that came with the HD cable box should be able to do that with ease.


It doesn't matter, the mute when no signal function applies to the outputs, which are all analog.

Also, I agree with your seperate remotes logic, even a step further as I don't have cable or any sort of TV. Only wealthy bachelors can afford HD cable:whew: 

Bosso


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## SteveCallas

No TV or cable? No football? How many movies do you typically watch in a month? 

As for the HK muting with no signal, I never considered that that might be why it was dead quiet. I'll try muting my Yamaha later tonight to see if I can replicate the dead silence in the tweeters.


----------



## Guest

Ilkka said:


> It did the testing also with this configuration and the result was exactly the same as when you disable the center. 4.1, 3.1, 2.1, 4.0, 3.0, 2.0 - same SPL loss compared to 5.1 or 5.0.
> 
> 
> Just like he says, only the DTS part is incorrect. I tested it too and DTS doesn't behave the same. There is no loss if you disable the center or surrounds. DTS doesn't carry any DRC information. Surprisingly DD 5.1 was only around 2 dB behind DTS at the same MV setting (Master and Commander).
> 
> So do remember that this happens only when playing DD tracks, DTS doesn't have this problem.




Just as a folow up, I ran some DTS tests on my system.

When I turned the center channel OFF, then DTS sounded the same as the full 5.1 sound.

When I turned the surrounds OFF, then DTS lost 6 dB of peak volume.

I have my mains set to large, and all other speakers are set to small, plus a subwoofer. There is no compression, but there is some type of change in either bass redirection or mix levels (or both) when the surrounds are set to off. I suspect it is simply bass redirection. Not sure if you get the same results if your mains are set to small.

Anyhow, DTS does sound good when you downmix. The downmix of DD sounds bad due that DRC downmix override function!


----------



## Guest

SteveCallas said:


> As for the HK muting with no signal, I never considered that that might be why it was dead quiet. I'll try muting my Yamaha later tonight to see if I can replicate the dead silence in the tweeters.



I have Sony receiver, and from what I can figure out only the analog inputs do not use a mute function. The digital inputs are hard to "listen to" if there is no digital input due to the typical mute function.

Anyhow, if you listen to a passage recorded at a very low volume on any active digital input, you can get a good idea of how quiet your system is. I can't hear any background "hiss" at -5dB from Dolby Reference Level MV settings when I am 1-foot from my speakers, so I am a very happy camper. 

WARNING: You must know what you are listening to so you don't get blasted by high volume when you least expect it!


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## Jman

What about the output option? If you set it to 2/0 stereo or 3/2+sw 5.1 there is a big difference in Speclab


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## Ilkka

J_Palmer_Cass said:


> Just as a folow up, I ran some DTS tests on my system.
> 
> When I turned the center channel OFF, then DTS sounded the same as the full 5.1 sound.
> 
> When I turned the surrounds OFF, then DTS lost 6 dB of peak volume.
> 
> I have my mains set to large, and all other speakers are set to small, plus a subwoofer. There is no compression, but there is some type of change in either bass redirection or mix levels (or both) when the surrounds are set to off. I suspect it is simply bass redirection. Not sure if you get the same results if your mains are set to small.
> 
> Anyhow, DTS does sound good when you downmix. The downmix of DD sounds bad due that DRC downmix override function!


That is really strange. I alse tested the same and max peaks were always identical. I could turn off the center, surrounds or both - no change (and my mains are set to large too). AFAIK DTS doesn't contain any DRC info. Which movie (scene?) did you try and which receiver you have?


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## Ilkka

Jman said:


> What about the output option? If you set it to 2/0 stereo or 3/2+sw 5.1 there is a big difference in Speclab


You should use 2/0 stereo. Spectrum Lab monitors only mains channels, so all the material should be in them. You should also turn off "auto gain control" and "bass redir".


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## Guest

Ilkka said:


> That is really strange. I alse tested the same and max peaks were always identical. I could turn off the center, surrounds or both - no change (and my mains are set to large too). AFAIK DTS doesn't contain any DRC info. Which movie (scene?) did you try and which receiver you have?



It is just the bass management of my reciever (Sony STR-DA4ES).

In some modes LFE and redirected bass are sent to both the R & L mains as well as the subwoofer. When I set the surrounds to OFF, then redirected bass goes to the R & L mains only, and only LFE goes to the subwoofer.

It is just a subwoofer calibration issue. I have to set my subwoofer down by 5 dB when LFE and redirected bass are sent to both the mains as well as the subwoofer. Same calibration method you use for running dual subwoofers.

Same issue when I set all the speakers to small. When they are all set to small, I have to add the 5 dB of gain back into the subwoofer input to get my bass back into calibration. I never use the downmix mode, so I never documented the bass redirection of my receiver in those downmix modes.


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## eddthompson

Just to dig this up, i was exploring through the menus in my denon reciver, and lo and be hold there was :

Dolby Digital Downmix Dynamic Range Compression : on/off

well who would have thought :bigsmile: if you use less than 5.1, have a look into denons 

edd


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## Ayreonaut

That's cool, what model do you have? 

I don't see that menu option anywhere on my AVR-1905, but it's one of their lesser models.


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## eddthompson

i have the K-AVC1-SE , i dont know the american model number, but its one of their $3000 amps. I got it used for $1200, the uk is so expensive sometimes, even for used gear.

edd


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## Guest

Here is a posting from the AVS forum by Rober Dressler (Dolby). This should help out with this issue. It seems like the vast majority of receivers use the DRC ON method when performing "speaker management". It seems like some here have the DRC OFF when downmixing option. My receiver does not have that!


Anyhow, you learn something new everyday!!!


--------------------

Roger Dressler 
Advanced Member


Join Date: Jul 2000
Location: CA
Posts: 916 Quote:
Originally Posted by SpectralD
Unfortunately, it is actually in the Dolby spec that DRC is engaged whenever downmixing occurs. Shockingly, this includes downmixing LCR -> LR. They refer to it as 'overload protection DRC' in the docs. 

Go figure. 

Allow me to clarify. Downmixing can take many forms. In a DVD player, a 2-ch downmix is always (I have not seen an exception, but who knows) done with DRC activated. This ensures the average level is maintained while preventing clipping. 

In an AVR, 2-ch downmixes will probably be done the same way. However, if it is desired to downmix without DRC, every Dolby Digital decoder IC knows how to do it. The output level is scaled down 11 dB, then there's no way to cause clipping. 

In the case of "speaker management" as descibed here, the AVR may allow the decoder to run in full 5.1 mode, no DRC, then downmix the C into L/R with the usual -3 dB mix level. With a little bit of scaling in the DSP, clipping can be prevented, and the gain is made up in the analog stage. 

The AVR maker can use this method, or they can use the "downmix in the DD chip with DRC on" method. It's their choice.

The tests described by others will show which mode the AVR is using. 

__________________
Roger


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## Ilkka

eddthompson said:


> Just to dig this up, i was exploring through the menus in my denon reciver, and lo and be hold there was :
> 
> Dolby Digital Downmix Dynamic Range Compression : on/off
> 
> well who would have thought :bigsmile: if you use less than 5.1, have a look into denons
> 
> edd


Many receivers do have DRC control (mine too), but it doesn't seem to affect while downmixing (ie. it's overruled). Could you check whether your Denos does this too? Just run a short dynamic scene with center on and off. Check the peak SPL with your SPL meter. Are they identical?


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## Guest

Ilkka said:


> Many receivers do have DRC control (mine too), but it doesn't seem to affect while downmixing (ie. it's overruled). Could you check whether your Denos does this too? Just run a short dynamic scene with center on and off. Check the peak SPL with your SPL meter. Are they identical?



Ilkka,

That DRC control is not the same as our DRC control.

The optional control that Ed has is special (and optional). It refers to downmixing in particular. Not sure how many receivers in any price range have that option.

"Dolby Digital *Downmix* Dynamic Range Compression : on/off"

Anyhow I use a full 5.1 system, so this it does not even apply to me right now. I was considering not using a center speaker in a second system that I am putting together, but I gave that idea up a while back after I figured out this DD downmix mess. The funny thing is that many people still insist that you can live without a center channel. If you question them, they respond like it's like a personal insult.

Put down the Sony STR-DA4ES in the DRC is applied during DD downmixing pile!


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## SteveCallas

> The funny thing is that many people still insist that you can live without a center channel. If you question them, they respond like it's like a personal insult.


Lol :R In regards to audio, some people can't handle the truth.


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## Ilkka

Sorry, I thought Ed meant the "normal " DRC. Though I would still like to see him testing it. 

Many people insist that you can live without a center channel speaker. I was one of them until I discovered the DRC thing. I don't need center channel speaker for sound stage etc. because I always sit at the sweet spot. But due this DRC thing I now have to consider buying it... :thumbsdown:


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## SteveCallas

> I was one of them until I discovered the DRC thing. I don't need center channel speaker for sound stage etc. because I always sit at the sweet spot. But due this DRC thing I now have to consider buying it... :thumbsdown:


Well not only are you going to get better highs and lows, you are going to spread the workload out over more speakers. Assuming you buy a third identical speaker, aside from having to spend money, this is a good thing.


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## eddthompson

ill give it a test as soon as i get a chance, my system is in a mess right now due to my projector failing, my satelite box failing, and a power amp, i beilve some kind of power surge has knocked them all out.


yes there were on a surge protected socket !!

edd


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## Guest

Steve,

How many receivers have you tried this phantom center downmixing on? Were they THX units or non-THX units? Did you get the same results each and every time? 

Just trying to figure out if this is a brand issue, a THX or non-THX issue, a high or low end product issue, an age of receiver issue or just a hit or miss issue!


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## SteveCallas

The testing I did was on an older RCA receiver and an Audio Refinement Pre-2DSP. I never bothered to try this on my current receiver after seeing Ilkka's measurements, but I can try it out tonight if you like. My current receiver is a Yamaha HTR-5890, it's a THX Select 2 certified, though I never engage any THX processing. We can get into a whole discussion on how that butcher's your highs and lows too, but we'll save that for another day  

My guess is that it will be a hit or miss issue, with it being mostly hits.


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## Guest

Yes, I would like to know the results of your new receiver. Maybe THX requires the "better" type of downmixing in order for the receiver to get the THX rating. Perhaps that is one of those un-documented THX requirements.

I also expect this to be a hit or miss issue, but for the next receiver that I buy I would prefer not to worry about this issue. I have a partial second system that I am considering using with a phantom center. This is due to the fact of the non-availability of a matching center speaker.

Since you know what you are doing, you can do this test fairly easily. Anyway, at least I can trust your results to be truthful!


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## SteveCallas

Between the gym, Monday Night Football, and cooking, I forgot all about this :duh: I'll do it tonight.


----------



## SteveCallas

Ok, used WOTW with the pod coming out of the ground, set my MV to -20. First, locked on to DD but played back in downmixed 2.1 stereo, recorded a max level of 98db. I let the scene play on to the point where the pod plays its horn. Then switched to 5.1, and quickly replayed the pod playing it's horn - VERY noticable difference in clarity, presence, and volume for the better. Started the scene over again. I hit 102db pretty early in and decided to stop right there, it is a Tuesday night 8:00 PM afterall :R If I let it play on, I probably would have gotten a couple db higher, but no need - even a THX Select 2 certified receiver is using dynamic range compression when downmixing DD 5.1 to 2.1.

Off topic - I use an upconverting dvd player with a 1080p set, and the majority of SD dvds upscaled to 1080i by the player then 1080p by the set look VERY good. Some even look better than the best real HD content I have seen from Charter HD. That said, WOTW looked good, but was grainy, especially when there was (artifical) smoke on on screen, like when they show the zoomed out view of the area with the pod standing up. Don't know what that's all about, I have much older dvds that look better :scratch:


----------



## MACCA350

SteveCallas said:


> Ok, used WOTW with the pod coming out of the ground, set my MV to -20. First, locked on to DD but played back in downmixed 2.1 stereo, recorded a max level of 98db. I let the scene play on to the point where the pod plays its horn. Then switched to 5.1, and quickly replayed the pod playing it's horn - VERY noticable difference in clarity, presence, and volume for the better. Started the scene over again. I hit 102db pretty early in and decided to stop right there, it is a Tuesday night 8:00 PM afterall :R If I let it play on, I probably would have gotten a couple db higher, but no need - even a THX Select 2 certified receiver is using dynamic range compression when downmixing DD 5.1 to 2.1.


But how much of this is due to the fact that there are 3 less speakers playing, and how much is due to the dynamic compression. 

The only way I can see that would discount the effects of having less speaker playing is to:
1. Set all speakers to LARGE

2. Turn any 'Double Bass' or 'LFE+MAIN' features OFF

3. Unplug all speakers except 1 (either sub, Left or Right)

4. Place SPL meter about 1 meter from the speaker (make sure it is not moved throughout testing)

5. Now test both full 5.1 and downmixed 2.1 (with the meter set to fast and slow at least 3 times each for consistency and check peaks and average. Also check than receiver DRC is off and that the Dialog Norm Offset is the same under all testing)

I might try this on the weekend

cheers


----------



## Chrisbee

I bought a matching center speaker and have now given up on analogue stereo from the DVDP for films. My old Yamaha DSP E800 3.1 processor with all speakers carefully calibrated produces the best SQ in DD5.1 and DTS. 

Analogue stereo from the DVDP + LFE (via a mixer) doesn't work because rear channel information is downmixed to the stereo channels. This badly confuses the surround effect.

The stereo output from my DVDP seemed to have slightly more noticeable sibilance compared with Main-out from the 3.1 processor when using a center speaker and setting "LFE to Mains".

The addition of rear and center speakers lifts the film watching experience to a completely different level compared with stereo. No matter how good the subwoofer playing on the stereo channel signal it is even better with surround sound, LFE and no dynamic compression! DTS seems even more dynamic with better bass and SQ than DD5.1 in my system.


----------



## SteveCallas

> But how much of this is due to the fact that there are 3 less speakers playing, and how much is due to the dynamic compression.
> 
> The only way I can see that would discount the effects of having less speaker playing is to:
> 1. Set all speakers to LARGE
> 
> 2. Turn any 'Double Bass' or 'LFE+MAIN' features OFF
> 
> 3. Unplug all speakers except 1 (either sub, Left or Right)
> 
> 4. Place SPL meter about 1 meter from the speaker (make sure it is not moved throughout testing)
> 
> 5. Now test both full 5.1 and downmixed 2.1 (with the meter set to fast and slow at least 3 times each for consistency and check peaks and average. Also check than receiver DRC is off and that the Dialog Norm Offset is the same under all testing)


Hmm, I really don't think there is need for such testing. If you cue up the pod emerging scene from WOTW, you'll notice that the loud parts are all bass, low bass. This is confirmed not only from just listening, but also from seeing my sub amp activity light light up during peak output levels AND reviewing SpectraLab measurements of that scene. It's what got sent to the sub that increased the max output level, not the addition of more speakers, as they weren't contributing too much at that peak moment anyway.

Could the horn have sounded clearer because it was louder? Yes, there's a possibility for that. Could it have sounded more present because it is coming from right in front of me as opposed to coming from the mains? Ehh, I wouldn't think so, as my mains are positioned to give stereo imaging right down the middle. Others have tried such a test and noticed the difference in bass - I'd encourage them to listen for more clarity in higher frequencies as well - this pod horn scene is a good example.



> The addition of rear and center speakers lifts the film watching experience to a completely different level compared with stereo. No matter how good the subwoofer playing on the stereo channel signal it is even better with surround sound, LFE and no dynamic compression!


Glad to hear


----------



## eddthompson

Chrisbee said:


> The addition of rear and center speakers lifts the film watching experience to a completely different level compared with stereo. No matter how good the subwoofer playing on the stereo channel signal it is even better with surround sound, LFE and no dynamic compression! DTS seems even more dynamic with better bass and SQ than DD5.1 in my system.


:bigsmile: woohoo.

Im sorry i have not tested my system, my projector is still broken, and the menus on my dvd player and amp are so hard without OSD, as soon as i get my projector working ill take some measurements.

edd


----------



## Guest

You know that I have found that many people just will not accept the fact that you need to have a full 5.1 system activated to get full dynamic range out of DD material. I wonder if the members of "that stubborn group" have DRC activated in their setup menu and just don't know that it is activated when they make their comparisons. I know that some just use the DTS track (if available), and then they proclaim how great DTS sounds as compared with DD.

The difference is so great that measurements with an SPL meter are not even required. SQ is also improved a lot.

There can't be that many affordable units on the market that downmix DD the "better way".

Still, it's kind of funny that DTS downmixes just fine!


----------



## Guest

SteveCallas said:


> Could the horn have sounded clearer because it was louder? Yes, there's a possibility for that. Could it have sounded more present because it is coming from right in front of me as opposed to coming from the mains? Ehh, I wouldn't think so, as my mains are positioned to give stereo imaging right down the middle. Others have tried such a test and noticed the difference in bass - I'd encourage them to listen for more clarity in higher frequencies as well - this pod horn scene is a good example.
> 
> 
> Glad to hear



The entire track is compressed, so all frequencies are "compressed". To me it sounds like going from hi-fi back down to mid-fi. Master and Commander is the worst of the bunch. The mixer must have chosen an aggressive DRC profile when he encoded that DD DVD!


----------



## SteveCallas

> You know that I have found that many people just will not accept the fact that you need to have a full 5.1 system activated to get full dynamic range out of DD material


Well it's just like anything in this hobby, most people aren't interested in the truth - they don't want to figure things out and move forward. Luckily this forum is pretty devoid of those types.

I agree that this is very likely the cause for many people to proclaim HUGE differences between DTS and DD.

Chris - so are you gonna get a new receiver?


----------



## Ilkka

MACCA350 said:


> But how much of this is due to the fact that there are 3 less speakers playing, and how much is due to the dynamic compression.
> 
> The only way I can see that would discount the effects of having less speaker playing is to:
> 1. Set all speakers to LARGE
> 
> 2. Turn any 'Double Bass' or 'LFE+MAIN' features OFF
> 
> 3. Unplug all speakers except 1 (either sub, Left or Right)
> 
> 4. Place SPL meter about 1 meter from the speaker (make sure it is not moved throughout testing)
> 
> 5. Now test both full 5.1 and downmixed 2.1 (with the meter set to fast and slow at least 3 times each for consistency and check peaks and average. Also check than receiver DRC is off and that the Dialog Norm Offset is the same under all testing)
> 
> I might try this on the weekend
> 
> cheers


I did my testing just like this. Only sub was playing, so DRC was the only thing accounting for the SPL change.


----------



## Guest

Interesting test.

Someone claims that when they run in phantom center, if they set the EX mode to matrix, then the dynamic range for DD material returns to normal. I have my EX mode set to auto, and I only run a 5.1 system. I have to run this test on my system.

I guess this is just another test for all who are concerned about the issue!


----------



## SteveCallas

> Someone claims that when they run in phantom center, if they set the EX mode to matrix, then the dynamic range for DD material returns to normal. I have my EX mode set to auto, and I only run a 5.1 system. I have to run this test on my system.


So they are saying that telling the receiver to matrix the rear surrounds on DDEX material turns dynamic range compression off, but not telling it to matrix the rear surrounds keeps it on? :scratch: I run 7.1, but I layer Pro Logic IIx on DD and DTS streams to extract rear channel information from 5.1 sources. Only relying on EX and ES discs to get use out of the surround speakers seems like a bit of a waste.

Makes me wonder, if they have no problem getting rears and only using them with maybe 5% of dvds, why are they so opposed to getting a center channel? :dontknow:


----------



## Guest

Steve,

Yes, you got it right.

It was just someone doing the test to see what happens when he ran in phantom center mode. I don't know if Master and Commander is a 6.1 DD EX DVD, but the poster claims that when he runs phantom center and turns EX from auto to matrix, then DRC is turned OFF and full dynamic range comes back.

To tell you the truth, I am not sure what EX matrix mode is supposed to do anyways. It may work on any 5.1 channel material as far as I know. I know the EX auto mode looks for the EX flag on the DVD, but I am not sure about the matrix setting.

I will test that out tonight on my system just to see what happens. I may have to set the rear surrounds to ON, but it will be interesting to see what I will end up with for results.

I also wonder if the people who insist that you need a great center channel speaker are the same people who add a center channel to their phantom mode systems. Then they hear a DD DVD with no DRC being applied for the first time, and think it their magical center speaker that makes the difference.

It's almost like the blind are following the blind. Magical speakers, magical cables, magical amplifiers, magical everything except magical intelligence!


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## SteveCallas

> I also wonder if the people who insist that you need a great center channel speaker are the same people who add a center channel to their phantom mode systems. Then they hear a DD DVD with no DRC being applied for the first time, and think it their magical center speaker that makes the difference.
> 
> It's almost like the blind are following the blind. Magical speakers, magical cables, magical amplifiers, magical everything except magical intelligence!


Bingo! That's why there is so much **** and myths in this hobby. That's also why we shouldn't take subjective impressions for much value unless they are our own subjective impressions - objective measurements are far more valuable. 



> It was just someone doing the test to see what happens when he ran in phantom center mode. I don't know if Master and Commander is a 6.1 DD EX DVD, but the poster claims that when he runs phantom center and turns EX from auto to matrix, then DRC is turned OFF and full dynamic range comes back.


Doesn't really make too much sense. DDEX creates a 6th channel that is matrixed from the surrounds, it's not discrete. I would imagine the difference between EX Auto or Matrix is that Auto will only create a single, 6th channel from the surrounds like it was meant to. EX Matrix probably doubles that into two rear channels. This is why I doubt using it would have any effect on dynamic range.


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## Guest

Steve,

I just looked it up. Auto requires the EX/ES flag to be encoded on the DVD. The matrix mode does not require the flag to be recorded on the DVD to get the decoding to work. The reason for this is some older DVD's do not have the flag encoded on the DVD.

My receiver is a 7.1 unit. It becomes 6.1 if I use one rear speaker, and 7.1 if I use two rear speakers. That is just a speaker selection issue, the decoding is the same either way.

You are right. It does make no sense at all that setting the EX/ES mode to matrix would change the downmix method, but who knows what goes on in these units. I wonder just how many unknown hardware/firmware issues are hidden in these receivers.

I have a Sony STR-DA4ES that has firmware version 1.00 installed in it. I have a copy of the updated firmware version 1.19 stored in my PC, but I am not sure if I should do the firmware update. I could screw it up if I am not careful!

Anyhow, I have gone as far as I can go setting up my system. I am thinking about installing ceiling mounted subwoofers in the ceiling bays in my future basement HT room. Has anyone tried this on this forum?


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## Guest

Hi Everyone,

I'm having the exact same downmix compression problem when watching DVD with my two channel audio system. Due to space limitation adding center and surround speakers is not an option for me. I do have a Velodyne DD-18 connected to the main speakers via speaker-level inputs. 

Any idea on how I can get around the downmix compression problem while sticking to only two channels? My Panasonic DVD has a compression option but even if I turned it off the audio still compresses. The extend of the compression is DVD-dependent as previous post confirmed.

Is there any DVD player that can downmix to two-channel SPDIF digital output w/o compression?

If not, is there any surround processor that can downmix to two-channel SPDIF digital output w/o compression?

Thanks.

Jack


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## SteveCallas

You'll either want to stick to DTS only or figure out a way to make 5 speakers work.


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## Ayreonaut

A center channel is not for everyone.
In many arrangements there's no _good_ place for a center channel speaker.
Many people prefer a phantom center and want to stick with two good mains.
I thought of a solution for this.
Use a separate amp (not the reciever) to power your mains.
Set the receiver to output full surround including the center channel.
Buy, commision, or build a simple mixer to mix the front three channels down to two. _No DRC._
I'm seriously thinking of doing that myself. It should work brilliantly, right?


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## SteveCallas

Maintaining discrete surround speakers?


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## Ayreonaut

I will be using discrete surrounds.


Jack Lee said:


> Due to space limitation adding center and surround speakers is not an option for me.


I'm not sure how space limitations could make surrounds a non-option. They can be pretty small. 

You can even put the surrounds in your ceiling.


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## Guest

I'm so glad I found this thread. I've been becoming increasingly discouraged with DD playback on my new 2-channel system. At first, I too thought it was just the difference from DTS which always sound great, but it was just so horrifically extreme I started suspecting there was some DRC being applied.

Unfortunately, even though there is a DRC setting on my NAD T753 under the "listening mode" it has no effect unless I turn the center and surrounds on. I thought it was a little odd that the late night mode didn't seem to do anything.

I intended to get the full 5.1 in the future, but my Magnepan mains already rather dominate the living room of our not-so-huge apartment (girlfriend factor here). If there is no way of disabling this DRC... rather than getting an external amp/mixer combo, would it work to run 5.1 with a mixer in a pre out/in loop?

I have to say that there are just a couple DVDs with DD only that actually sounds pretty good... The Incredibles in particular seems to retain pretty good range (actually the only reason I thought it MIGHT just be in how the movies were mixed).


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## Ayreonaut

jlamb said:


> ...rather than getting an external amp/mixer combo, would it work to run 5.1 with a mixer in a pre out/in loop?


A.1. If you output 5.1 to avoid DRC, you'll need surrounds.
A.2. You need a 7 channel receiver with 5.1 + Zone 2 output to create the loop. Some people have bi-amped their mains that way with success, but when I tried it the loop added an unacceptable level of noise.


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## Guest

Ok guys I need help since I noticed big difference between DTS and DD but I have different gear than most of you:
I watch usually DD5.1 movies from my PC and here's my gear:

Revolution 7.1 (used via digital out only!)
Presonus Central Station
Dynaudio BM6A (will go down to 45Hz)
So a 2.0 system...

So all DD/DTS decoding is done by AC3 filter (I have the latest version). The DAC in Presonus is just a stereo DAC so no decoding what so ever and no DSP either:
http://www.presonus.com/centralstation.html

My AC3 filter settings:




But when I watch DD5.1 material I get this:


The way I see it L is input and L' is output. So should I too correct to LFE/R' = 0 ?
Are other AC3F setings right?


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## eddthompson

i know im a bit late, but ive only just got everything back up and runing again.

With the centre speaker turn off on the power amp, using the new t2 blu-ray on the cyberdyne building explosion.

Standard DD 5.1 peak = 96db
Centre disabled peak = 86db
Centre disabled with downmix option = 96db
Standard DTS 5.1 peak = 95db
Centre Disabled peak = 95db

Pretty conclusive if you ask me, i expected DTS to be louder, but i dont think the DD track is using dial norm.

edd


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## Guest

Ayreonaut said:


> I will be using discrete surrounds.I'm not sure how space limitations could make surrounds a non-option. They can be pretty small.
> 
> You can even put the surrounds in your ceiling.


Yup. Problem is I'll need another amp for the center/surround speakers, plus (long) cabling. Pretty hard to do w/o major rennovation as apartments in Hong Kong usually neither have rugs (usually hardwood floors on concrete) nor dry walls (again concrete walls) to hide wires. :surrender: 

Actually even stereo-only is pretty good as the surround effects can be heard even w/o the surround speakers. It is just that annoying DRC and the missing ".1" LFE that takes away some of the sound effect's impact. :duh: 

To me (and probably many space-constrained members) the simplest solution would be to downmix everything to 2-ch. Maybe some software-based player in HTPC can do that?


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## Ayreonaut

I finally got around to checking my system to see if my reciever is applying DRC to DD. My Denon AVR-1905 does apply a mild amount of DRC when the center channel is set to none. I played the "Ring Drop" scene and watched the meter on my BFD and noted -3 dB reduction in the peak level. I would never have known except by direct comparison. Its something I will keep in mind as I upgrade, but not something I will shed tears over in the meantime. Nevertheless, I will probably stick to DTS when I show off my system!


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## SteveCallas

As J_Palmer stated, the denial can be astounding :rolleyesno: 



> I played the "Ring Drop" scene and watched the meter on my BFD and noted -3 dB reduction in the peak level. I would never have known except by direct comparison. Its something I will keep in mind as I upgrade, but not something I will shed tears over in the meantime


Remember that the amount of compression will vary from movie to movie, so while it may have only been 3db with LOTR ring drop, it can be a lot more with other films. Looks like Master and Commander is the worst offender so far.


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