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

[Newman]

I have seen a couple of comments in general discussions on ASR recently that the centre channel requires a more 'muscular' speaker than the left and right speakers. This is news to me, so I would like to check its veracity. I had assumed that Centre is used mainly to centre the dialogue in movies, and that most of the power-hungry content goes to the left and right. For music, I hadn't really thought about it too much... but kind of assumed that music mixes would allocate centre channel to vocals and highlighted solo instruments, but a lot of general energy would still be sent to left and right discrete.

I would like to understand what gets sent to the centre speaker. Is it any more demanding than what gets sent to the left and right speakers?

For music I would also like to know what the good up-mixers do. Do they allocate so much signal to the centre channel that it becomes more important than left and right to be an overall high-quality speaker including power and distortion?

Anyone here who actually mixes multichannel sound?

thanks

 

[tmtomh]

I had this same question - can't offer any answers but I am starting from the same working assumptions you are, and look forward to gaining some insight on this. Thanks for starting the thread!

 

[Blumlein 88]

I would like answers too. We may have play some stuff and record the results. I could manage that, but I would need to disconnect everything and make measures.

Probably easier to dump a 5.1 track into a DAW.

 

[tmtomh]

I would like answers too. We may have play some stuff and record the results. I could manage that, but I would need to disconnect everything and make measures.

Probably easier to dump a 5.1 track into a DAW.

I've only done that with a couple of music DVD-A rips (Led Zeppelin's How the West Was Won and the DVD-A of Beck's Guero), and in both cases the center channel had pretty much what one would expect: vocals and any other center-mixed instrumentation except bass, which went in the LF/.1 channel.

But my N here is only 2 so these could be outliers.

 

[alex-z]

If you listen to most movie mixes, the majority of the on-screen action comes from the centre, and the front L/R are used for steering.

The power being sent to it isn't actually that high, but you definitely notice when there is poor off-axis response or compression.

 

[Inner Space]

I have done OK with multichannel mixes over the years. Music and movies are diametrically different, in that movies are built from the center outwards, and music is built from L&R inwards (with a bit of outwards to the surrounds.)

The center channel for movies contains spot Foleys (i.e. sound effects directly related to centered physical activities), some score tailing in from L&R, but most importantly, virtually all of the dialog (except occasional offstage shouts from distance, etc.)

Thus from the mixer's point of view, for movies, the center channel is by far the most important. Ideally the center speaker should be the best you have, or at least no worse than the L&R. Choose it for voice reproduction. The idea that the center "anchors" the dialog to the screen is crucially wrong - it's the only source of dialog (apart from maybe wispy reverbs going to L&R & surrounds, if the action is in a cave.) For FR, you want about 80Hz upward - the fundamental of a deep male voice (although the "dark brown voice" used for some commercials and trailers can go down to 60Hz.)

Music is different, in that the center can be said to "anchor" the center image to the center of your space.

The easiest way to check this out - if you have a multichannel set-up - is to try both music and movies with the center speaker disconnected. You'll lose a bit with music, but movies will be a disaster - their lips will be moving, but you won't hear what they're saying.

 

[sarumbear]

I have seen a couple of comments in general discussions on ASR recently that the centre channel requires a more 'muscular' speaker than the left and right speakers. This is news to me, so I would like to check its veracity. I had assumed that Centre is used mainly to centre the dialogue in movies, and that most of the power-hungry content goes to the left and right. For music, I hadn't really thought about it too much... but kind of assumed that music mixes would allocate centre channel to vocals and highlighted solo instruments, but a lot of general energy would still be sent to left and right discrete.

I would like to understand what gets sent to the centre speaker. Is it any more demanding than what gets sent to the left and right speakers?

For music I would also like to know what the good up-mixers do. Do they allocate so much signal to the centre channel that it becomes more important than left and right to be an overall high-quality speaker including power and distortion?

Anyone here who actually mixes multichannel sound?

thanks

It’s easy to find out listen the LCR speakers on their own.

In my experience tge centre speakers carries the most audio energy in all modern movies I listened.

 

[More Dynamics Please]

Beyond dialog, if a movie features a center screen closeup of a gun being shot the report will come primarily from the center speaker, not LR. With special effects steered to the center as well as LR depending on screen location of the sound source the center should optimally be at least as capable as LR.

 

[restorer-john]

The easiest way to check this out - if you have a multichannel set-up - is to try both music and movies with the center speaker disconnected. You'll lose a bit with music, but movies will be a disaster - their lips will be moving, but you won't hear what they're saying.

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.

 

[Alice of Old Vincennes]

That is why must have (make) space for a large 3 way center.

 

[Inner Space]

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.

Exactly right. At home I use a simple 2.0 with speakers that give strong phantom images, and I'm very happy. Honestly, mono would be fine.

 

[aarons915]

I don't have any objective data on this of course but my opinion has always been that the 3 LCR should be identical and if the center isn't good enough to be a center it's not good enough as your LR either since you listen to music sometimes, which carries a full range signal. I don't think it matters much that more information is sent to the center as long as it is properly bass managed relative to it's limits. Bass is the only thing that really stresses speakers so as long as you cross them over high enough, the center doesn't need to be a powerhouse speaker in my opinion.

 

[MarcT]

I've always read and been told that, in movies, the center channel is full range and the most important channel. I understand that that doesn't tell you much about what is actually mixed to the center channel in any given movie.

My biggest wish for my center channel reproduction is for it to be able to properly play a deep male voice. I understand that the fundamental for a deep male voice may be ~80 Hz, but the problem is that, in some movies, they will enhance the male voice much deeper than that. If you ever get the chance to play the movie, The Mummy, with Russell Crowe, watch the scene in which Dr. Jekyl is revealed to be Mr. Hyde. This scene occurs in a huge room and when Hyde begins to speak, his voice was absolutely subterranean when I saw it at the movie theater. I don't know if the Blu-ray was mixed the same, but I don't get anything like that when I play that scene on my system, regardless of what subwoofer and crossover settings I try. My center speaker is a Polk LSiM 706c, which is supposed to play down to 50 Hz.

 

[gene_stl]

I also am very interested in this subject. I am very interested in upmixing my very large collection of CDs. I have been collecting information on this subject and can offer the following links but have not done it yet. (ie still listening in two channel stereo). I don't care much about movie sound only music which I think is what the OP said.

The SST Trinaural system designed by the late great Jim Bongiorno. $3000 currently for a one rack unit box with 10 or 20 op amps in it. I won't be spending that kind of money on that but would love to try one out.

Trinaural Processor — SST

Closer to the Live Event TRI-CHANNEL PROCESSOR The Trinaural Processor is a totally unique device that addresses what Jim Bongiorno considered an inherent flaw in the traditional music playback system—specifically, that it only produces sound in two channels. According to Jim, there is

www.sst.audio

http://static1.squarespace.com/static/5480969de4b0f0d437dda5d4/t/5759fc6e3c44d8a1c65bbdf4/1465515120087/SST+Trinaural-manual-v1.pdf

https://www.stereophile.com/musicintheround/904music/index.html Kal Rubinson review from 2004
https://audio-intl.com/wp-content/uploads/2018/03/Trinaural.pdf Another credible review of the Trinaural

The above are the only credible info sources I have run across lately on the Trinaural
If anyone wants to sell one for a reasonable price or let me borrow theirs to reverse engineer it I would be interested.



The subject has been brought up here at least once before.

gear that converts 2 channel stereo, to 3 channel (or more) ?

I use a McCormack MAP-1 analog preampflier, for music playback (no movies/home theater). It can be used as 2-channel preamp, but can also convert stereo input, to 3.1 or 5.1. This is done in analog, no digital processing. I enjoy the effect of creating a center channel for music...

www.audiosciencereview.com

The McCormack MAP 1 was $2395 in 2003.

There are a number of well known methods from equipment producers. These are hardware software combos.
The Meridian TriField seems to be well liked by folks that have their gear which is exspensive and somewhat rare.

Lexicon Users swear by the Logic 7 system which would probably be easier to catch an example of such a pre preamp /processor or AVR.

Auro 3D may be able to do the job in some implementations.

Dolby ProLogic II (music) can do this and is widely available on AVRs. It is said to be not that talented. But might be good for an initial try.
DTS and others probably can do this trick too.

There is a gadget that the Quadies at Quadroponic Quad love very much the Involve Audio Sound Master.
If you already have a 5.1 system it will upmix to that level. The designer told me he has a customer who added a box to reduce the upmix to 3.1. It required injecting reverse phase info to cancel the side surrounds. Seems like leaving there would be the way to go since the Surround Master (now on its third iteration is said to be "never offensive in its upmixing) It is about $695 from Australia

Home - INVOLVE AUDIO

involveaudio.com

New posts

www.quadraphonicquad.com

The Quadrophonic Quad web forum.

On the above site it was noted that there have been some other upmixers such as the late great Shure HTS5300 that could do a good job on this.
There is a build it yourself kit for a replica Dyna tube preamp that has a simply mixed center channel as some preamps from back in the day did.
I think a level control would be needed.

PAS-NGCT

Get the retro look combined with the modern sound of a new gen PAS built around the popular AIKIDO line preamp with solid-state power supply.

www.erhard-audio.com

Too expensive.

Finally there are software only implementations which can be done if you are willing to go to that effort and have the equipment.


These are for upmixing to surround but you can stop at adding a center channel

SurroundByUs.com • Index page

There is Spec software Spec Web and many others.
At QQ some of them use expensive mixing/DAW software to upmix including to 3.x


That is about all I know. I am interested in what anybody else has discovered.

 

[Alice of Old Vincennes]

I don't have any objective data on this of course but my opinion has always been that the 3 LCR should be identical and if the center isn't good enough to be a center it's not good enough as your LR either since you listen to music sometimes, which carries a full range signal. I don't think it matters much that more information is sent to the center as long as it is properly bass managed relative to it's limits. Bass is the only thing that really stresses speakers so as long as you cross them over high enough, the center doesn't need to be a powerhouse speaker in my opinion.

Until you listen to 3 way center with 6.5 woofers.

 

[aarons915]

Until you listen to 3 way center with 6.5 woofers.

Much of my experience is comparing my KEF R3/R2c setup to 3 LS50s as LCR, so quite a different amount of distortion and I prefer the LS50s crossed at 100-120Hz. I think a lot of this may have to do with our SPL levels, I watch movies closer to an average level of 75db at my listening position so I haven't noticed a difference between more capable centers.

 

[Blumlein 88]

Here are the 6 channels from Loki episode one. A movie with plenty of explosions and such in all the channels.
Order is L, R, C, LFE, left surround and right surround. In general terms of energy the center channel has the most going on.
Despite how it looks, the analyzer function shows the average level for the right and left tracks are only 3-4 db lower than for the center track in this one instance.

Listening to each track there is definitely zero dialog leakage into the left or right channel. Though the center channel has quite a bit of info similar to the left and right channel included. And surround channels do include echo like sounds of dialog at low levels. It does appear after I did some filtering that much of the LFE channel is included in the center. Though a few areas the center doesn't have what the LFE has. I'm guessing that varies with who mixed a video.

For what it is worth, I'd been using a JBL LSR305 for the center which I knew was too small for my moderately large video room. Switching to an LSR308 mkII resulted in about what is subjectively a 25% or so improvement. Now I need a smooth Harman speaker with the efficiency of a K-horn it looks like.

PS_All I did was open the movie video file with Audacity and it provides this. I'm on Manjaro linux and I seem to recall in the past Audacity acts differently if on a Windows machine for such multi-channel files.

 

[raistlin65]

I have seen a couple of comments in general discussions on ASR recently that the centre channel requires a more 'muscular' speaker than the left and right speakers. This is news to me, so I would like to check its veracity. I had assumed that Centre is used mainly to centre the dialogue in movies, and that most of the power-hungry content goes to the left and right. For music, I hadn't really thought about it too much... but kind of assumed that music mixes would allocate centre channel to vocals and highlighted solo instruments, but a lot of general energy would still be sent to left and right discrete.

I would like to understand what gets sent to the centre speaker. Is it any more demanding than what gets sent to the left and right speakers?

For music I would also like to know what the good up-mixers do. Do they allocate so much signal to the centre channel that it becomes more important than left and right to be an overall high-quality speaker including power and distortion?

Anyone here who actually mixes multichannel sound?

thanks

Do you have a home theater set up with 5.1 or even more speakers?

If so, unplug your center channel and try watching some TV and some movies clips. That will definitely give you some insight.

And then you can try it, too, with music surround enabled and see what happens to your music.

 

[restorer-john]

Exactly right. At home I use a simple 2.0 with speakers that give strong phantom images, and I'm very happy.

Exactly what I do.

Mains that do mids/voices incredibly well with rock solid imaging completely negate the inclusion of a compromised centre. In fact I have half a dozen centres lying around that only get used as test speakers for repairs on my bench- I gave up listening to centres a very long time ago- they would all make me cringe.

You also have no issues with the centre phantom images being shifted in the horizontal plane by non-ideal placement above or below the screen.

 

[Newman]

re: upmixing

The Meridian TriField seems to be well liked by folks that have their gear which is exspensive and somewhat rare.

Not realistic option

Lexicon Users swear by the Logic 7 system which would probably be easier to catch an example of such a pre preamp /processor or AVR.

Not available and "catching an example" is not at all realistic outside US, like me.

Auro 3D may be able to do the job in some implementations.

Yes. No experience but that is being reported by others.

Dolby ProLogic II (music) can do this and is widely available on AVRs. It is said to be not that talented. But might be good for an initial try.

Tried this and the DTS equivalent. Terrible downgrade in soundstage quality IMO and in the opinion of everyone I demonstrated on. Vocals become clear but a tiny pinpoint in space and lose their impact and effect. Even worse, the same happens to all the instrumental soundstage that was panned to centre in 2-channel.