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The Problem with Many Center Channel Speakers (by Erin)

Matias

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This is a "must see" for anyone buying center speakers! Fantastic video by Erin (@hardisj).

 

Badou

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So this means, for us europeans, the two best speakers ranges for Home theater at a reasonable price point are the SVS prime series, and the Kef Q series.
Still waiting for the Monitor audio silver 7g measurements for a third contender tho.
 
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Matias

Matias

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So this means, for us europeans, the two best speakers ranges for Home theater at a reasonable price point are the SVS prime series, and the Kef Q series.
Still waiting for the Monitor audio silver 7g measurements for a third contender tho.
The Silver C250 7G should have good horizontal dispersion because of the mid+tweeter on the center. But sure an actual measurment would be great.

ma_silver_c250_front_black_oak_angled.jpg
 

HooStat

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Agree on the Monitor Audio center. The Polk Legend center looked really good on Audioholics (not sure if available in Europe). Would love to see that one measured here too.
 

HooStat

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I noticed the Polk crosses over at 260 Hz (5 ¼" mid) and the Monitor Audio crosses at 650 Hz (3" mid). KEF R2C crosses at 400 Hz. Revel C426Be crosses at 210 Hz while the Revel C208 crosses at 375 Hz. Not sure if that means anything but it seems that the "better" speakers might be pushing the crossover from the mid to the woofer as low as possible. Which makes me wonder about the Monitor Audio a bit. The ELAC Uni-Fi 2.0 center crosses at 200 Hz, and, for $370 seemed to have pretty good response and dispersion. Maybe pushing the limits of a 3-way design though.
 

YSDR

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I noticed the Polk crosses over at 260 Hz (5 ¼" mid) and the Monitor Audio crosses at 650 Hz (3" mid). KEF R2C crosses at 400 Hz. Revel C426Be crosses at 210 Hz while the Revel C208 crosses at 375 Hz. Not sure if that means anything but it seems that the "better" speakers might be pushing the crossover from the mid to the woofer as low as possible. Which makes me wonder about the Monitor Audio a bit. The ELAC Uni-Fi 2.0 center crosses at 200 Hz, and, for $370 seemed to have pretty good response and dispersion. Maybe pushing the limits of a 3-way design though.
The lower the crossover frequency, the lesser the lobing effect (with a horizontal speaker layout, it's a horizontal lobing) caused by multiple drivers use, because the wavelengths involved are bigger. But this way, the midrange driver needs to work harder to keep up the required SPL (and/or senitivity) with the tweeter and the woofer(s), the passive crossover parts needs to be larger values (for the woofers and the for the midrange too), which are significant, because they are usually proportionately more expensive.
But even, not every midrange driver can cope with a low crossover point, the small midrange of the Silver 7G probably can't. All is a compromise.
 

Astojab

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If I understand the video correctly isn't a Bookshelfspeaker with good horizontal dierectivity (like the Kf R3) actually better than most MTM-Center speakers?
 

voodooless

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If I understand the video correctly isn't a Bookshelfspeaker with good horizontal dierectivity (like the Kf R3) actually better than most MTM-Center speakers?
Yes, but an R3 is a bad example since it’s a coaxial already. A normal 2-way bookshelf would do just fine. Don’t put it in it’s size though (you can wij the R3)
 

Chickasaw Mudpuppy

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So this means, for us europeans, the two best speakers ranges for Home theater at a reasonable price point are the SVS prime series, and the Kef Q series.
Still waiting for the Monitor audio silver 7g measurements for a third contender tho.
Amazon DE was practically giving away the Monolith 365 center channel for 240 euros around Xmas time,I almost pulled the trigger my I couldn't bear the thought of looking at its ugly mug above my tv plus I've got no real reason to replace the one I've got
 

bjmsam

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Excellent video! That ripple tank simulator offers an effective way to visualize energy in a room. While attempting to model the comb filtering described in the Share Your In Room Measurements thread, I noticed the interference introduced by a center speaker and wonder if that might contribute to the challenges so many seem to have with proper integration (and my preference for phantom; recent example of myriad threads: Please Share Your Center Channel Experiences), even when the driver configuration is optimal?

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JEarle

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Excellent video! That ripple tank simulator offers an effective way to visualize energy in a room. While attempting to model the comb filtering described in the Share Your In Room Measurements thread, I noticed the interference introduced by a center speaker and wonder if that might contribute to the challenges so many seem to have with proper integration (and my preference for phantom; recent example of myriad threads: Please Share Your Center Channel Experiences), even when the driver configuration is optimal?

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That combing would only occur if the Left, Right and Center where all producing the same signal though, correct?
 

bjmsam

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That combing would only occur if the Left, Right and Center where all producing the same signal though, correct?
Combing occurs any time multiple sources emit the same frequency content. My simulation above is worst case (same frequency, phase, and amplitude), but content often overlaps channels (e.g.- panning), and as the center is closer to the MLP than the left and right (~13" or ~1ms in my case), the effect for common frequencies could be similar to an early reflection. Or not?
 

tuga

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Excellent video! That ripple tank simulator offers an effective way to visualize energy in a room. While attempting to model the comb filtering described in the Share Your In Room Measurements thread, I noticed the interference introduced by a center speaker and wonder if that might contribute to the challenges so many seem to have with proper integration (and my preference for phantom; recent example of myriad threads: Please Share Your Center Channel Experiences), even when the driver configuration is optimal?

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The benefits of a centre channel are dealt with in great detail in @Floyd Toole 's book Sound Reproduction: The Acoustics and Psychoacoustics of Loudspeakers and Rooms
https://www.amazon.co.uk/Sound-Reproduction-Psychoacoustics-Loudspeakers-Engineering/dp/113892136X/

It is curious that some people hear enough of a problem with the phantom center stereo image to embark on research to fix it, while others condemn a real center channel loudspeaker as being inferior to a phantom image. It is a situation complicated by inconsistencies in recordings and human adaptation to stereo after decades of exposure. As shown in Figure 10.15a, the radiating pattern, the directivity, of a human voice is very similar to that of a conventional cone and dome loudspeaker. Logically it should do well as a reproducer of a solo voice (Figure 7.1c) compared to the artificially complex sound field associated with a phantom center image (Figure 7.1b). Listening away from the sweet spot eases the phantom image timbre problem, but then the soundstage is distorted from what was intended. A center channel avoids the timbre problem, stabilizes the soundstage for more listeners, and is less sensitive to room effects.


I can understand the potential benefits of adding a centre channel from an imaging/soudstanging perspective but that simulation does not bode well for the tonal accuracy side of things...
 
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