Center channel for Home Theater

[Benedium]

I've noticed many dedicated center speakers (yes including the dreaded but common mtm ones) have sensitivity that is at least as high or higher than their same series floor standing speakers. Any reason for this?

I suspect it may be important to know why especially if we alternatively plan to use a less sensitive speaker like a bookshelf speaker for center channel. So should a speaker for center channel always be more sensitive than the other speakers in a home theatre?

 

[Benedium]

I've noticed many dedicated center speakers (yes including the dreaded but common mtm ones) have sensitivity that is at least as high or higher than their same series floor standing speakers. Any reason for this?

I suspect it may be important to know why especially if we alternatively plan to use a less sensitive speaker like a bookshelf speaker for center channel. So should a speaker for center channel always be more sensitive than the other speakers in a home theatre?

Ok found this thread on audioholics in case anyone is interested...

front vs center channel speaker sensitivity

How close do the sensitivity ratings need to be for the front vs. center channel speaker? I am considering using a 89db sensitivity rated speaker for the center channel, that would be matched up (same brand, similar drivers, etc) with 92db sensitivity rated fronts? Thanks.

forums.audioholics.com

 

[Sancus]

Sensitivity is irrelevant in all contexts as long as you have enough amplifier power to reach the desired levels. That's all it's good for, to roughly calculate that. And even then you're better off with a proper FR measurement of the speaker if available.

 

[alex-z]

I've noticed many dedicated center speakers (yes including the dreaded but common mtm ones) have sensitivity that is at least as high or higher than their same series floor standing speakers. Any reason for this?

I suspect it may be important to know why especially if we alternatively plan to use a less sensitive speaker like a bookshelf speaker for center channel. So should a speaker for center channel always be more sensitive than the other speakers in a home theatre?

In an MTM design, sensitivity is naturally somewhat high, as the woofers overlap for additional output, requiring less resistance in the tweeter circuit to be level matched. In a proper 3 way design, it may be lower, depending on the specific drivers used. A low impedance mid-range driver will make the overall design more sensitive, but may result in a speaker which AV receivers have difficulty driving.

Sensitivity has no relationship to sound quality. The radiation pattern and frequency response need to match your other speakers.

 

[Soundmixer]

First the better Eq systems will decrease the differences between center and L/R speakers and even the surrounds

And yet there will still be differences, and they will likely be audible. Too much dependence on EQ systems to correct for poor speaker design, or mismatched speakers will likely lead to poor sound in the end.

 

[Ozymand1as]

IME horizontal center speaker design (2- or 3-way) on-axis and directivity characteristics never match the LRs. If you look at Amir and Erin's data, you can see that even KEF concentric drivers don't have exactly the same directivity and in both planes. The R3 is the closest I believe.

Seems to me trying to "match" LCR is a fools errand unless they are the same speaker in the same orientation. Different speakers are different, no way around it. I feel like Erin has a video about this...

 

[Sancus]

IME horizontal center speaker design (2- or 3-way) on-axis and directivity characteristics never match the LRs. If you look at Amir and Erin's data, you can see that even KEF concentric drivers don't have exactly the same directivity and in both planes. The R3 is the closest I believe.

Exact matches are not important though. You just don't want a significantly audible difference. An MTM paired with standard L/R is significant, coaxial differences are not.

 

[sword]

And yet there will still be differences, and they will likely be audible. Too much dependence on EQ systems to correct for poor speaker design, or mismatched speakers will likely lead to poor sound in the end.

Have you had any experience with this though? I've used three different center speakers, even two "dreaded" MTM designs, with my mains, and they blended nicely after calibration. The only noticeable difference came at reference level, because the MTM's didn't have the output capability of the mains. None of them sounded poor.

 

[sword]

This post sums up my experience nicely.

https://www.avsforum.com/threads/should-your-center-speaker-match-the-same-brand-as-your-front-left-and-front-right-speakers.3174026/#post-60275367

 

[Soundmixer]

Have you had any experience with this though?

Yes, hence my answer.

I've used three different center speakers, even two "dreaded" MTM designs, with my mains, and they blended nicely after calibration.

Blended nicely is great, but I like my center speaker to sonically disappear. That can only happen if the three front speakers are the same and are properly calibrated.

None of them sounded poor

I am sure this is true from your perspective.

 

[Haint]

Yes, hence my answer.

Blended nicely is great, but I like my center speaker to sonically disappear. That can only happen if the three front speakers are the same and are properly calibrated.

I am sure this is true from your perspective.

Not just the same speaker, they also need to be at the same height on the same type of stand, and even then I'd have my doubts. In my mid-field media room (~7 foot MLP, perfectly symmetrical, treated) a third identical bookshelf as the center sounds very different from the mains. Mains are on 24" stands, center is on an 18" media console. Different floor bounce, different side wall reflections, different SBIR= radically different sound. Calibration improves it, but it's not a perfect match. Even with a projector and acoustically transparent screen with all 3 LCR's at the same height, I think the differing side wall reflections and SBIR effects will still produce a different sound. I imagine it's less of an issue in an untreated room from a further distance where you're hearing much less of the speaker and much more of the room/reflections.

 

[Soundmixer]

Not just the same speaker, they also need to be at the same height on the same type of stand,

Floor standers don't need stands, and you can tilt up your center speaker to account for a lower height.

a third identical bookshelf as the center sounds very different from the mains. Mains are on 24" stands, center is on an 18" media console.

I am pretty sure the height is not as much an issue as the fact that you have two speakers on stands and one speaker on another surface. In my music room, all three of my front speakers are on stands, but the center is 6" lower than the L/R mains. All I did was tilt back the center speaker, and you could not audibly tell it was at a different height.

 

[Odorb]

Floor standers don't need stands, and you can tilt up your center speaker to account for a lower height.

I am pretty sure the height is not as much an issue as the fact that you have two speakers on stands and one speaker on another surface. In my music room, all three of my front speakers are on stands, but the center is 6" lower than the L/R mains. All I did was tilt back the center speaker, and you could not audibly tell it was at a different height.

I'm considering doing that, if I can get 3 m126be speakers. Which stands did you go with? I'll have them under a TV so was thinking of getting 3 low stands and tilting them all up a little.

 

[Teeter]

With my front main speaker heights, the L/R tweeters are at ear height. The center channel is at ear height.

I have had mains with a center channel of a different mfg., and was okay with it. I might go back to my psb Imagine XC and see if there is better movie dialog over the ELAC. The current ELAC C5.2 is good to my Sr. ears.

 

[Teeter]

Here is a center channel review and you will have to scroll down to click on the video.

The problem with (most) Center Channel speakers

I have been wanting to address this topic for a while. I've got a LOT of hours into this, from measurements to sound recordings to building the presentation. My hope is that it will provide insight into problematic designs and help people understand how to use objective data to get a better idea...

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