What SHOULD An HT Center Channel Speaker Sound Like?

[mj30250]

But that's not the case in 2.1 and 5.1 film audio recording. It's the dialog channel. And it's probably why so few 'center channel' speakers are the same specs as mains.

The reason most center channel speakers aren't spec'd the same as mains is not because of dialogue concerns, but because most people using dedicated centers don't have room to effectively turn a big tower on its side and plunk it under their display. If you have an acoustically transparent screen or simply have an uncommonly large amount of room beneath your display, the "correct" course of action would be to place a third identical speaker in the center position. If it's a high quality speaker properly configured for your room, dialogue should be perfectly clear and intelligible (unless, of course, the source mix is poor). If your mains happen to be small bookshelf speakers, this becomes easier.

 

[Sancus]

If what you say is correct, why do cinematographers call the center channel the "dialog channel?" Every film sound guy I ever knew calls it that.

Probably because it contains almost all of the dialog, it's a colloquialism. But that's not ALL it contains. It also contains most of the sound effects, some of the music, etc. There is no hard barrier between channels in surround sound. Things are panned across them and the LCR usually all contain some part of the sound or some reverb even if they're not the primary source.

Just watch a movie and solo the center and then solo the L or R. It only takes 2 minutes to find out that there's a lot of stuff in there other than dialog. There is a reason that the center channel has an average level of 3dB higher than ANY other channel. It's because that's where the majority of the sound is.

I dunno what sorts of conversations you're having, but it's common knowledge among audio engineers that the center carries most of the audio and that you should put foley(sound effects) in the center by default, among other things.

The best center channel is identical to the L/R and that is supported by all of the research and information on this topic.

 

[Kal Rubinson]

If what you say is correct, why do cinematographers call the center channel the "dialog channel?" Every film sound guy I ever knew calls it that.

Sloppy language skills.

 

[Chrispy]

But that's not the case in 2.1 and 5.1 film audio recording. It's the dialog channel. And it's probably why so few 'center channel' speakers are the same specs as mains. They're best intended to reproduce dialog clearly, probably not so much cannon fire. But here, we bitch because they often aren't "hifi".

Can you point me at a 2.1 recording (movie or music)? Never heard of such myself, but could be interesting.

 

[Chromatischism]

I can't see why one would subtract the 150-5k Hz... Destructive interference is a fact of life for any and all multi-speaker layouts playing some of the other speakers' content.

The reason most center channel speakers aren't spec'd the same as mains is not because of dialogue concerns, but because most people using dedicated centers don't have room to effectively turn a big tower on its side and plunk it under their display. If you have an acoustically transparent screen or simply have an uncommonly large amount of room beneath your display, the "correct" course of action would be to place a third identical speaker in the center position. If it's a high quality speaker properly configured for your room, dialogue should be perfectly clear and intelligible (unless, of course, the source mix is poor). If your mains happen to be small bookshelf speakers, this becomes easier.

The reason is because there is no market for them, because it doesn't fit in people's preconceived notions of an "entertainment center".

 

[MKR]

This is a very interesting discussion … Does anyone have any experience with the Revel Voice 2? I am considering purchasing one but very expensive and if it has same directivity issues as all other centers then no way I will proceed. And how important is it that the “voicing” (timbre?) of center to mains is same/similar (similar drivers as mains)? I have read this often but wonder how critical it really is. To say, if I have Salon 2s as mains, any issue to use something like a KEF center with coaxial driver that avoids the directivity issues? (assuming Voice 2 has such an issue)

Note I tried to find measurements of the Voice 2, especially directivity, and there is zilch.

Thanks

 

[voodooless]

Does anyone have any experience with the Revel Voice 2? I am considering purchasing one but very expensive and if it has same directivity issues as all other centers then no way I will proceed.

It doesn’t. It has a vertical tweeter and mid. That should yield good directivity if the filter is done correctly. Generally Revel does proper work there.

 

[mj30250]

 

[Salida]

This is a very interesting discussion … Does anyone have any experience with the Revel Voice 2? I am considering purchasing one but very expensive and if it has same directivity issues as all other centers then no way I will proceed. And how important is it that the “voicing” (timbre?) of center to mains is same/similar (similar drivers as mains)? I have read this often but wonder how critical it really is. To say, if I have Salon 2s as mains, any issue to use something like a KEF center with coaxial driver that avoids the directivity issues? (assuming Voice 2 has such an issue)

Note I tried to find measurements of the Voice 2, especially directivity, and there is zilch.

Thanks

No direct experience but similar experience with a timbre matched center. So, first, I feel your pain. These center speakers seem to be priced in a predatory manner.

I have Amati Futura mains and ended up buying their Amati Vox center. Similar configuration to the Revel with a vertically aligned tweeter and midrange. No directivity issues common in OoO designs.

I have a front projection system, about 8’ wide screen. The results have been excellent.

The visual and aural clues combine to place dialog and effects where they should be on the screen. It’s pretty cool.

I’ve had unmatched centers/main before and never had this degree of spatial realism.

 

[norman bates]

To repeat what others have said, center should sound just like what your left and right speakers sound like.

I'm of the camp that believes the center should be the same as the right and left speakers.
The surround setup would be even better if rears were the same loudspeaker also.

Initially (25 years ago) I had 4 big cerwin vega 3-ways with 15" (dx9).
I ran 2 in the front and 2 for rears.
Different surround settings no longer sounded like a tin can.
Then I tried 3 across the front (L/c/R).
That sounded great, and like above said, the spacial clues made sence.

Later I used 5 cheapy yamaha 3-ways (with 8"), worked great.
Then lastly had 3 cerwin vega 3-ways (again), the v12f across the front.

 

[NiagaraPete]

Why do we test home theatre dialog (center channel) speakers as if they are expected to be like mains?

Is it unreasonable to expect HTCC speakers to be optimized for human speech? Yet we persist in expecting them to have the same quality and character as the main front channel speakers. We know the range for intelligibility of the human voice, and it ISN'T 20 Hz to 20 kHz. It's more like 150 Hz to 5kHz. And it should be cardioid, not all beamy with 2 woofers and two tweeters.
.....
Further, why doesn't anybody make a powered center channel speaker for HT? In adding a center channel to a 2.1 system to accommodate HT, why can't we just take the high-level lines to the main channel speakers, feed them as signals into an amp in the center channel, and use bandwidth shaping to accommodate dialog, not all the music and car crash sounds? Is Atmos a law of nature?

As a crowd of one, but possibly more, I would like very much to buy a single box, place it dead center in front of the TV, plug it in, connect a couple of small signal leads to the main channel speakers, tune it up, and voila! have better dialog. And not have to step back to a sound bar, or up to a rack of hardware, MDF boxes, and more remote controls to do it.

Klipsch, Polk, Emotiva, and all the rest: why is there no such product?

-Just one guy's view, who's anti-wire clutter and 7.1.1 contraptions.
[stepping aside and awaiting all the it-can't-be-done testimonies.]

You can use a single Genelec for centre.

 

[milotrain]

For whatever it is worth: Every single movie or TV show you watch (for the most part) was mixed in a room where the L C R were all the same speaker. The center channel does the most work out of all the speakers in the array, both because almost all the dialog lives in the center but also because the center supports the backgrounds, contains most of the foley, and much to most of the sync sound effects. Everyone who works in the industry calls it the center channel, it is not called anything else.

I mix TV for a living, have spent around two decades in the industry as a sound professional. Have worked on features you've all seen and TV shows you've all heard of.

 

[restorer-john]

The idea that it's a "dialog speaker" is very wrong.

That's all it needs to be, and all it was ever designed for in the first place.

There's zero need for anything other than a dialog anchor on the screen if your mains are good enough.

 

[Sancus]

That's all it needs to be, and all it was ever designed for in the first place.

There's zero need for anything other than a dialog anchor on the screen if your mains are good enough.

I mean this is completely wrong and you literally could have read the post above yours from an actual professional or any of the links in my post to other professionals.

Or simply check what's in the centre on any content.

Posting wrong things repeatedly doesn't magically turn them right.

 

[milotrain]

That's all it needs to be, and all it was ever designed for in the first place.

There's zero need for anything other than a dialog anchor on the screen if your mains are good enough.

So, if "Bob" is talking, that's in the center "dialog" speaker, but his footsteps are in the L&R? What about the phone that rings in his hand? What about the sound of him drinking?

 

[restorer-john]

So, if "Bob" is talking, that's in the center "dialog" speaker, but his footsteps are in the L&R? What about the phone that rings in his hand? What about the sound of him drinking?

Bob speaks out of both the left and right channels and as if my magic, Bob appears rock solid in the centre. And Bob can even move where ever he wants and with him, his voice goes too. Amazing huh? Hopefully you understand the concept of imaging, I would hope so.

Centre channels are completely unnecessary except for people sitting way, way off centre and that was and is, easily solved with a dialog (LP and HP filtered) centre derived from the L+R. That is what @Jim Shaw is also suggesting and I agree with him. I've got plenty of centres lying around. I use them for for amplifiers I want to soak test with no risk to speakers I actually value.

Putting unnecessary sounds outside basic dialog and a similar range of frequencies, into a centre channel just means 99% of people with small setups and compromised centre speakers in not-ideal placements will experience timbral and image shifting across those three front channels. They'll simply miss half the garbage that shouldn't be there in the first place. The best speakers in a typical HT are the mains. The most powerful low distortion amplifier channels in a typical AVR are the mains. The worst performing speakers are pretty much always the centres.

I only ever did HT with all identical full range 3 way mains, centres (x2) and surrounds back in the day. The first things to go were the centres. I heard a supposed SOTA multi hundred thousand dollar HT only a few months ago and the "demo" left me cold. Point source effects with no envelopment. No real sense of width across the stage and a complete inability to reproduce even 2ch stereo content or accurately image with any sense of realism.

I want to hear the actors- they are the cake we come to eat, the rest is just the icing.

 

[milotrain]

What audio stream are you pulling then? The stereo? Or are you taking a 5.1 mix and multing the center channel to the L+R?

Putting unnecessary sounds outside basic dialog and a similar range of frequencies, into a centre channel just means 99% of people with small setups and compromised centre speakers in not-ideal placements will experience timbral and image shifting across those three front channels.

1. You don't mix to the lowest common denominator, that's how you get the crappy music mixes of the 80s that were made to sound good on car speakers. You trust that your work will outlive today's technology.
2. Explain to me how you would approach this with a bussing structure and a pan law in any current DAW. Pro Tip: I suspect you'll end up defining a 4.1 system, but of course you know that such doesn't exist, which means it's not possible to deliver to the end user.

I want to hear the actors- they are the cake we come to eat, the rest is just the icing.

If you want a "tell me" medium you go to theatre or radio plays. TV/Film is a "show me" medium; as such the visual world must be justified with sound. That sound isn't as important as dialog, but it is more than just icing.

Yes, obviously every speaker in the front array is the same. This has been covered.

 

[dshreter]

The converse is true, thus (lack of) the speaker is the problem. If dialog intelligibility weren't a common problem, what use would we have for any center channel, ever??

I come from the avionics world where we worry a lot about speech intelligibility. A hifi speaker over a passenger's head makes intelligibility worse than one optimized for the human voice. The same for the captain's microphone and the air controller's headphones. Hifi can make a muddle of dialog.

You’re blending together all sorts of concepts. But yes, it is possible to have a center channel dialogue speaker with lower fidelity and higher intelligibility.

Sonos on their amp and speakers has a feature called dialogue enhancement for example, that makes dialogue easier to hear and understand.

General hifi theory though is that you want your system as high fidelity as possible, and let the content do the interpretation instead. If they want dialogue to be clearer, they can record their audio to achieve that too. If they want the dialogue to be muddy, then they can get across that artistic intent.

You’re right that current speakers don’t do much to enhance intelligibility. My take, that’s something best left to signal processing instead of speakers so it can be turned on and off as appropriate. I also don’t think that needs to be strictly for center channels either.

 

[Jim Shaw]

I want to hear the actors- they are the cake we come to eat, the rest is just the icing.

Thanks for this. This is what movie sound recordists and post sound editors strive for. None of them, that I know, record and process for effects over intelligibility. It's why they uniformly refer to any captured center channel as the "dialog channel." Dialog is very commonly captured, on set, by a monaural microphone. Later, it is mixed into the tracks.

If the movie viewer cannot clearly understand the actors' spoken lines, the scene audio won't be salvaged by the exact aural image of some footsteps or a passing truck. The Oscar goes for the actors' lines, foremost. The paying audience cares about them.

 

[restorer-john]

1. You don't mix to the lowest common denominator, that's how you get the crappy music mixes of the 80s that were made to sound good on car speakers

That comment suggests you weren't even around in the 1980s. No idea.