The Centre channel: what signal gets sent to it? How demanding compared to Left and Right?

[tecnogadget]

Or switch it the centre to Phantom and find out how much you have been missing in terms of accurate voice reproduction by using a crappy centre.

Some Series/shows are mastered only in stereo…and when you have a proper HT setup with good quality center, and mains, it’s almost instantly felt how it lacks the accuracy of having the center channel information in the mix (5.1/7.1). Luckily Pro Logic II Movie can upmix it and provide you center channel info and get you 80% of the way (vs discrete center voices). Even doing this 2.0 vs Pro Logic comparison, the center channel wins over phantom image every single time.

 

[raistlin65]

What would deny the assertion

I don't know. You posted the other information, and commented that it doesn't support the assertion. I just pointed out it doesn't deny it either. lol

 

[Newman]

What would deny the assertion?
How about Dolby guidelines saying they need the same capability

The assertion is that the centre needs to be more muscular than left and right. Not equal.

 

[Inner Space]

The assertion is that the centre needs to be more muscular than left and right. Not equal.

"Muscular" is suggestive but vague, so put it this way: for movies and TV, the center carries all the content you need to enjoy and understand the production - dialog, effects, score, etc. L&R and surrounds are progressively less important - music and ambience in the L&R, random crap, really, in the surrounds. So if a lightning storm took out everything except the center, the vital communication of essential information would not be much inhibited. For that reason alone, the center speaker's competence is the most important. It carries loud dynamics and needs uncolored articulation. I think of "5.1" as "1 + 4.1". Certainly the idea of having fancy L&Rs and "any old" center makes no functional sense at all.

 

[flyzipper]

The assertion is that the centre needs to be more muscular than left and right. Not equal.

Distilled down, I'll take Dolby's spec as the authoritative voice on the matter.

It's your question though, so it's entirely possible I'm missing what you're asking.

Isn't the evidence that mastering studios who create the mixes using the same speakers for LCR, and professional theaters who earn money by playing them back for wide audiences also using the same speakers for LCR, in conjunction with Dolby writing the spec stating the LCR speakers have the same requirements -- those aligned industry approaches don't debunk the more muscular requirement you've heard from individuals in the forums?

The only way I can see it not, is if personal preference enters into the discussion, like when people prefer tube amps over those that test objectively better on the material metrics. If somebody wants to run a jacked-up centre channel because they watch movies in a noisy environment and their hearing isn't what it used to be, that's their choice to make, but when we start discussing that it needs to be more muscular, that's prescriptive.

Again, maybe I'm missing something, which is why I asked what would deny the assertion that a centre needs to be more muscular?

 

[abdo123]

This info about the preponderance of the center channel info are very helpful. Is there a way to look at the low frequency extension and level in the center channel signal in movies or TV shows?

It’s completely full-range. The playback setup should be the one doing bass-management.

 

[Blumlein 88]

Yes, because the center channel is full range, and gets lots of use in movie or music mixes, I think I'm adding a sub to my two way center speaker. I added some newer subs recently and have a smaller 10 inch one left over. So add to the center, and the center will gain by not having to handle low frequencies, and the low frequencies will be better produced than they are presently.

 

[raistlin65]

"Muscular" is suggestive but vague, so put it this way: for movies and TV, the center carries all the content you need to enjoy and understand the production - dialog, effects, score, etc. L&R and surrounds are progressively less important - music and ambience in the L&R, random crap, really, in the surrounds. So if a lightning storm took out everything except the center, the vital communication of essential information would not be much inhibited. For that reason alone, the center speaker's competence is the most important. It carries loud dynamics and needs uncolored articulation. I think of "5.1" as "1 + 4.1". Certainly the idea of having fancy L&Rs and "any old" center makes no functional sense at all.

It would be interesting to get something like one of those electric usage monitors that you can plug into the wall, and then plug your device in to see what kind of voltage and power it's using.

But instead, measure the output to the center channel from an AVR, versus the output to a left or right speaker.

 

[Sancus]

The assertion is that the centre needs to be more muscular than left and right. Not equal.

This is false imo, it should be the same. But not less, either, which is the way people usually go.

While the center tends to be the loudest channel on average for film/tv, it's only by 3dB, and the Dolb/DTS specs are also clear in that the front channels have the same SPL requirements.

Also you should have enough headroom in your speakers that +/- 3dB is not material, especially considering bass management.

 

[Blumlein 88]

It would be interesting to get something like one of those electric usage monitors that you can plug into the wall, and then plug your device in to see what kind of voltage and power it's using.

But instead, measure the output to the center channel from an AVR, versus the output to a left or right speaker.

What would that tell you that knowing the relative signal levels doesn't already tell you?

 

[HooStat]

I think the "more muscular" idea exists because at times, the center channel has to produce the same volume as the combined output of the left and right. Which is why you sometimes see (as shown earlier in this thread) the left and right down by ~3 db each, compared to the center.

Assuming this is accurate, that doesn't mean the center has to be "better" than the left and right. It depends on the listening level and the left and right speakers. I think the point is simply to illustrate that the center channel can, at times, need to provide more output than the individual left and right channels. So it needs to be capable of doing that. If it can produce 85 db with 20 db peaks (or whatever specification you care about) then it is fine.

This is what I have gathered from reading through some posts on this topic. I could be wrong, and I am happy that the OP put this question out there.

 

[MarcT]

It’s completely full-range. The playback setup should be the one doing bass-management.

Well, I know the center channel is a full range channel, and I'm not interested in bass management. My question is how much really low frequency information is typically mixed to the center channel(just the actual center channel information, not LFE) in Blu-ray or streaming movies.

 

[MarcT]

Yes, because the center channel is full range, and gets lots of use in movie or music mixes, I think I'm adding a sub to my two way center speaker. I added some newer subs recently and have a smaller 10 inch one left over. So add to the center, and the center will gain by not having to handle low frequencies, and the low frequencies will be better produced than they are presently.

I'm thinking of doing likewise. The goal would be to augment the deep base of the center channel speaker enough to put it more on par with my front L/R speakers, which are very large towers. I run the front L/R as LARGE and I also like to run the center channel LARGE. The LFE still goes to the sub.

 

[Newman]

Yes, because the center channel is full range, and gets lots of use in movie or music mixes, I think I'm adding a sub to my two way center speaker. I added some newer subs recently and have a smaller 10 inch one left over. So add to the center, and the center will gain by not having to handle low frequencies, and the low frequencies will be better produced than they are presently.

I’m not running my centre as full-range in the AVR setup settings, so I expect the above is happening anyway. The LF is being routed to the sub. No point in adding a dedicated sub to it...

 

[Newman]

This a Mozart 5 channel recording from 2L music. All 5 channels have near equal level in this. And they do use the LFE channel just a bit.
Looking at a few more 2L tracks I have they appear to all be put together in the same way as this one.
View attachment 171931

Thanks for these. Do you have an example with a featured vocalist?

 

[Newman]

OK the summary of all the feedback I have read, IMHO, is that if you are totally focused on TV and movies, and want to save some money, then it probably would do no harm to spend big on the centre and get a bit more economical on the left and right. Example: Genelec 8361 centre, 8341 left and right.

That might be the scenario that led to the ‘more muscular centre’ comments I had been seeing. (I had not realised that, before starting this discussion. Thanks for the input guys.)

But for music, the evidence I am seeing so far, you could actually do the opposite (again, to save some money).

And yes, overall, it seems that identical LCR is optimal for music and movies taken together. But that often won’t mean 3x 8361; instead for real budgets it might mean 3x 8341. Who is going to argue that is the better choice if you can afford to upgrade the centre (movie focus) or the left and right (music focus)?

So, for a given real-life budget, you might be better off spending a bit more on centre if your priority is TV/movies, or the left and right if you prioritise music.

Those are my thoughts so far.

cheers

 

[beaRA]

Anthony Grimani shows a graphic at 31:56 in this video suggesting that the center channel is on average 3dB louder than the left and right channels. This is supposedly a long term average over the full length of 12 film tracks.

 

[flyzipper]

OK the summary...

I see where your reasoning lead you to that conclusion, but your summary also highlighted where my assumptions (and bias) leads me to a different conclusion.

Under the constraint of, "for a given real-life budget", and using your equipment options, I would opt for 3x Genelec 8341 and use the savings over the 8361 ($5350.00 - 3125.00 =$2225.00 in Canada) on the .1 channel. The .1 budget would double if I'm reading your (music focus) example correctly, and it has 2x 8361s that I could replace with 8341s.

With a sub, the 8361's 30Hz response becomes less consequential versus the 8341's 38Hz response.

Also, the 8361's 118dB SPL rating versus the 8341's 110 dB rating is a non-issue for the ranges I listen at.

That's the lens I was looking at this problem through -- subwoofers are a given in a 5.1 setup (in my world, at least).

 

[Momotaro]

I expect a proper Atmos or other object-oriented mix and decode should work fine with 4.n.n configurations but I haven't tried it. Of course I've had barely audible dialog trying some older multichannel soundtracks when just L and R speakers are present (no centre) but that's a limitation of the older tech. There's no hard physical requirement for a centre speaker in a smaller room, assuming your system can do a wide, stable soundstage (my phantom centre doesn't collapse if you sit in front of either L/R main speaker for example, ymmv though). The need arises if the mix requires it. Most people will just have a soundbar though, so the question is moot.

 

[Newman]

I see where your reasoning lead you to that conclusion, but your summary also highlighted where my assumptions (and bias) leads me to a different conclusion.

Under the constraint of, "for a given real-life budget", and using your equipment options, I would opt for 3x Genelec 8341 and use the savings over the 8361 ($5350.00 - 3125.00 =$2225.00 in Canada) on the .1 channel. The .1 budget would double if I'm reading your (music focus) example correctly, and it has 2x 8361s that I could replace with 8341s.

With a sub, the 8361's 30Hz response becomes less consequential versus the 8341's 38Hz response.

Also, the 8361's 118dB SPL rating versus the 8341's 110 dB rating is a non-issue for the ranges I listen at.

That's the lens I was looking at this problem through -- subwoofers are a given in a 5.1 setup (in my world, at least).

Yes and Floyd Toole has chipped in with his view on a very similar question, link. He saves even more on the mains and diverts $$ to (more) subs.

I am comfortable with yours and Floyd’s approaches.