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post #31 of 47 Old 06-28-2012, 09:34 AM
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Quote:
Originally Posted by Eyleron View Post

Phantom Centers



For one listener dead center in sweet spot, I don't think a separate center speaker will help to separate center channel content better than a phantom center would, all other things being equal. Meaning, the center speaker must be of the same caliber and positioned as well as the other two front speakers.

But, for people far off-axis, sitting to the sides of the theater, the phantom center doesn't work as well. The two speakers being of unequal distances will make the timing be off between the front and right speakers trying to generate a phantom image. And the soundstage will be more heavily dominated by the near front speaker, with the center channel content being more diminished.

Weak Centers



Still, that pain might be less than the harm done by using a weak center speaker with respect to the other front speakers. If you like to run the system louder with peak levels over a 100dB, so you bought two front speakers with a 10" woofer and 6" mid and two tweeters, or a horn, the you will be disappointed by a center with a couple three inch mid-woofers, or even a couple 6" woofers. The center will have become the weak link in the chain.

And it's not just voices coming out of the center. Explosions, orchestral pieces, laser beams, the pounding of horse hooves, etc.
If you use a disadvantaged center speaker versus capable more stereo fronts, you're saying, "I want high output for the front-left and front-right sound channels, but for 60%-80% of the movie (coming from the center channel), I want it to clip, sound harsh and strained and not as loud."


Or, you just don't turn movies up loud, and thus you don't make much use of those capable stereo fronts in cinema mode, and you reserve them for stereo music. Which is cool...but people should be aware of their system's goals and limitations.

 

Thank you. This is what I try to explain on this issue, but the vast majority of folks advocate just using these small speakers and crossing them over at 80hz or even higher. But, as you say, the center channel is full range, and I want to hear these dynamic effects coming from the actual center speaker, as much as possible, not from a sub. And as I said above, I do hear a lot of directional bass sounds coming from my front L/R speakers. So why not from the center speaker?

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post #32 of 47 Old 06-28-2012, 09:36 AM
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Originally Posted by commsysman View Post

Some people think that bigger is better for center speakers.
Since the purpose of a center speaker is midrange center-fill, this is kind of dumb.
A center speaker should have a frequency range of 120 to 3000 Hz, and should not go much higher or lower.
4-inch drivers without tweeters will cover this range, actually, so most center speakers are times 10 overkill.
The sound QUALITY of those speakers is what is important, for good clarity.
I would definitely stay with the A4; I am quite certain that it will play as loud as needed with no distortion, unless the AMPLIFIER distorts, which has nothing to do with the speaker.


Centers are for midrange center-fill?

In all the Dolby, THX, and articles by hometheaterhifi etc., I've never read this.

When the dialog, let alone any other sound effect or music piece, is only encoded for the center channel, then you think the mixer's intent is the voice not have any airy sibilants? I'm amazed that you could think this.

 

4" drivers overkill?

Secondly, driver area is not only about the frequency range...it's also about output level. Tiny headphones will produce 30Hz, right? Thus, one might conclude that for a music stereo system, one could get away with a tiny subwoofer with a 7mm driver? While that might work in "Barbie's Home Theater" set, it will not have nearly the output one desires sitting more than a half inch away from the speaker. So we use bigger drivers, because sit many feet away.

 

Likewise, while a 4" driver is adequate for 120Hz at low to mid-levels, it won't be nearly capable of higher SPLs.

 

Amplifier distorting not related to the speaker?

How about: if the speaker is not sensitive enough for the goals of the system and for the amplifier, then the amp will get turned up to the point of distortion? I say the amp WILL distort, if the speaker cannot play as loud as needed, which will be likely with your 4" driver.

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post #33 of 47 Old 06-28-2012, 10:09 AM
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Originally Posted by commsysman View Post

Most people muddy up the sound by having the subwoofer set to go too high, where it overlaps the front speakers and creates problems. The subwoofer should NEVER operate at the same frequencies as the front speakers, and it should only be used ONLY at the frequencies that the front speakers CAN NOT reproduce!
A subwoofer should NEVER be set to go above 50-60 Hz or so, and the front speakers should be set to go down to 50 Hz, or 60 at the very least. Front speakers that don't go that low are inadequate and should be replaced.
As for someone's baritone voice, that is entirely above 100 Hz, and a properly set subwoofer is never going go that high or have any affect whatever on the reproduction of any human voice; that is ridiculous! The range of human voices is from 100 to 1200 Hz, and a baritone does not go down below 140.
A 4-inch driver can reproduce any human voice from top to bottom and anything larger is inappropriate and may not work as well.
The QUALITY of the driver is far more important than its size for voice reproduction.
Oddly enough, some speakers that cost several thousand dollars, which I have owned, sound marvelous for music and not always optimal for the human voice.
By the way, the best-sounding speakers I have ever heard for the accurate reproduction of the human voice are the Gallo CL-3 speakers, which I recently purchased.
One TV program we regularly watch, "Foyle's War", has always annoyed the heck out of us because it is so hard to understand the dialogue; the quality is bad and the British speech patterns don't help.
The first time we watched it using the Gallo speakers, we were unexpectedly amazed by the clarity of the soundtrack and the ease of understanding it. We knew the speakers were amazing for music, but we hadn't expected that.
Our previous speakers were fairly expensive, and very good for music, but didn't do much for dialogue.

Wow.. Other people have addressed your points but you should really stop trying to offer advise to people on this forum until you actually understand what it is you are talking about.

Just wow...
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post #34 of 47 Old 06-28-2012, 10:12 AM
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Originally Posted by joms View Post

What is the advantage of using a bigger center speaker other than being able to have a louder max volume?


If i only have a rather small bedroom (15sqm), would it be pointless to upgrade my center speaker say from a polk audio RTi CSi A4 to an RTi A6? or paradigm CC-590 to CC-690


Say that I use my system for 90% movies 10% music

I'm going to put the vertical vs. horizontal speaker alighment issue aside as that's a whole 'nother argument.

If your mains are polk RTi's then stick with polks for your center. They are likely designed to work together. Most movies use the center speaker for dialog any way.

That being said, in a small bedroom, I would get the cheapest speaker in the lineup that accurately reaches 80Hz. I would then use the speaker setup on the receiver to set the center channel to small and redirect the bass (below 80Hz) to the sub or main.

Speaker design is rather an art. There is no such thing as the perfect painting. Likewise there is no such thing as a perfect speaker. It's part science and part personal preference.
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post #35 of 47 Old 06-28-2012, 10:20 AM
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Quote:
Originally Posted by Eyleron View Post


Weak Centers




And it's not just voices coming out of the center. Explosions, orchestral pieces, laser beams, the pounding of horse hooves, etc.
If you use a disadvantaged center speaker versus capable more stereo fronts, you're saying, "I want high output for the front-left and front-right sound channels, but for 60%-80% of the movie (coming from the center channel), I want it to clip, sound harsh and strained and not as loud."

This is rarely an issue if you pick from the same manufacturer lineup. Speakers of the same product line are designed to work together and typically have similar power ratings and frequency response. A doubling of wattage is only a 3dB difference which is barely audible to human ears.

Speaker design is rather an art. There is no such thing as the perfect painting. Likewise there is no such thing as a perfect speaker. It's part science and part personal preference.
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post #36 of 47 Old 06-28-2012, 10:21 AM
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Quote:
Originally Posted by Eyleron View Post

Phantom Centers



For one listener dead center in sweet spot, I don't think a separate center speaker will help to separate center channel content better than a phantom center would, all other things being equal. Meaning, the center speaker must be of the same caliber and positioned as well as the other two front speakers.
 
Unless some dynamic compression is engaged to avoid clipping the now combined channels.

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post #37 of 47 Old 06-28-2012, 10:27 AM
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Quote:
Originally Posted by DigitalGriffin View Post

This is rarely an issue if you pick from the same manufacturer lineup. Speakers of the same product line are designed to work together and typically have similar power ratings and frequency response. A doubling of wattage is only a 3dB difference which is barely audible to human ears.

It depends on the goals of the listener. I have a friend who blows up his center paradigm all the time but his mains just distort at the same level, also paradigms. 3 dBs can be audible if it is the 3 dBs necessary for the speaker to not compress or distort. The center channel has more information than both the Left and right speaker during movies. Every channel has full bandwidth content, if you want to compromise the center that is your choice, but not ideal.
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post #38 of 47 Old 06-28-2012, 10:57 AM
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So you could get some benefit with a big center speaker by using a lower crossover, say 60hz compared to 80hz?? Assuming the center has low enough bass extension.
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post #39 of 47 Old 06-28-2012, 12:12 PM
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Originally Posted by csgamer View Post

So you could get some benefit with a big center speaker by using a lower crossover, say 60hz compared to 80hz?? Assuming the center has low enough bass extension.

Even though bass is directional below 80Hz, the THX std is set at 80Hz and most receivers follow this in their crossover. So unless your receiver has an adjustable cutoff, 60Hz won't do you much good.

Speaker design is rather an art. There is no such thing as the perfect painting. Likewise there is no such thing as a perfect speaker. It's part science and part personal preference.
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post #40 of 47 Old 06-28-2012, 12:14 PM
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Originally Posted by MKtheater View Post

It depends on the goals of the listener. I have a friend who blows up his center paradigm all the time but his mains just distort at the same level, also paradigms. 3 dBs can be audible if it is the 3 dBs necessary for the speaker to not compress or distort. The center channel has more information than both the Left and right speaker during movies. Every channel has full bandwidth content, if you want to compromise the center that is your choice, but not ideal.

Most speaker blowouts are in the tweeter, not woofer. And that's usually the result of transient spikes (clipping) Between the same product line, the tweeter RARELY changes between mains and center.

That vast majority of energy wattage wise goes woofers below the 80Hz range.

And claiming you get compression in the 3dB range being audible is like saying "I can't hear distortion with 1 dynamite stick. But I can sure hear it with that dynamite stick + firecracker!"

Speaker design is rather an art. There is no such thing as the perfect painting. Likewise there is no such thing as a perfect speaker. It's part science and part personal preference.
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post #41 of 47 Old 06-28-2012, 12:22 PM
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Originally Posted by csgamer View Post

So you could get some benefit with a big center speaker by using a lower crossover, say 60hz compared to 80hz?? Assuming the center has low enough bass extension.

Well, that's up for debate, and depends on what you are looking for. Some don't care about hearing anything below 80hz from the center speaker.

And, yes, you could cross over at 60hz or even 40hz. There are center channel speakers that play down into the 20s, but they are large and expensive. Here is my pipe dream center channel speaker:

http://www.legacyaudio.com/products/view/marquis-hd/

And there are others as well.

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post #42 of 47 Old 06-29-2012, 03:00 AM
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If we're crossing the speakers at 60/80Hz, sending the lower frequency to subwoofer, is there still a need to get speakers with woofers larger than 6.5"?
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post #43 of 47 Old 06-29-2012, 05:09 AM
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I will share my experience with you:

My previous speakers were B&W Matrix 805 speakers. I had three identical that I used for left/right/center. These are a well received two way design with a 6 1/2" woofer. I set my HT pre-amp to crossover to the sub at 80hz.

When the opportunity was given to me to purchase a single Aerial Acoustics LR5 (vertical version of the CC5 center) I put it in place to serve as my center channel speaker. I could not afford three new Aerials so I took my old Polk RTA11t towers out of storage to use for left/right to hold me over until i could afford two more LR5's. The match was less than ideal but at least the Polks were comparable in size.

All I can say is "wow". I remember the feeling that this was not an incremental upgrade with diminishing returns, The center channel was so good it even made my old Polks sound better. Is that because of the driver size, the number of drivers, crossover or something else? I don't know but the Aerial provided a night/day difference for the better.

I made no changes to my crossover settings so I never changed from the 80 hz crossover. I did experiment lower at 40hz (my old lexicon does not offer anything between 40,80,120 and large) but preferred the 80hz point.

Comparing the bigger center: even crosssing over at the same frequency the Aerial sounds much better. The sound is fuller with more weight and body. It seemed to add more depth to the soundfield. The Aerial is an amazing speaker. The smaller speaker sounded "small".


So, I strongly disagree with the philosophy that it makes no difference what size speakers you use as long as you are crossing over the LFE to a dedicated subwoofer. Making the move to the Aerial LR5 has been the most significant upgrade to my HT. I am fortunate now to have a complete set of three LR5's for my fronts. Changing out my Polks for the Aerials on left/right made an improvement in panning, but, the overall increase in the performance of my HT was not as significant as when I upgraded the center. I guess this supports the claim that the center channel is the most important speaker in HT.

David Lynch Current Equipment: Marantz AV8801, Proceed HPA3, Parasound HCA-1206, Aerial Acoustics LR5's (LCR), Aerial Acoustics LR3's (sides), RBH in-walls (rears), Seaton Submersive, Marantz VP15s1, 106" Carada BW screen, Oppo BDP-103.
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post #44 of 47 Old 06-30-2012, 04:09 AM
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Great thread - just what i was curious about tongue.gif
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post #45 of 47 Old 07-05-2012, 10:28 PM
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And claiming you get compression in the 3dB range being audible is like saying "I can't hear distortion with 1 dynamite stick. But I can sure hear it with that dynamite stick + firecracker!"

No, you have it backwards. It goes from a negligible value to an exponentially large value. I have watched distortion rise dramatically as I reached limits of speaker and amp. 3db is twice the amp's watts requirement. If you were already near clipping at 120 Watts, and then you ask for double at 240 Watts (by turning up the volume 3db), what do you think the distortion is going to look like?
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post #46 of 47 Old 07-05-2012, 10:42 PM
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Quote:
Originally Posted by Skylinestar View Post

If we're crossing the speakers at 60/80Hz, sending the lower frequency to subwoofer, is there still a need to get speakers with woofers larger than 6.5"?

Really, when one asks about centers in particular, it is starting out with a flawed premise, that the needs are somehow different from the other the speakers.

So if you're asking about speakers in general... Yes, the need exists for volume. When you look at sub reviews you see how an eight inch driver may reach 20 Hz, but at really low volumes. You add inches to get more SPL.

Analogously, a 6.5" driver can only put out so many decibels at 100 Hz. As you get closer to reference level, it will fall short, unless it's beefy and able to handle 500 Watts or something.

This is the reason that people who happily crossover their front speakers to subs will still use front drivers of 8, 10, 12 inches, like the eD Cinema, JTR T8, CHT Sho10, and pro speakers.

Likewise, it is why one would use them for center speakers.
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post #47 of 47 Old 07-07-2012, 12:02 AM
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Quote:
Originally Posted by Eyleron View Post

Really, when one asks about centers in particular, it is starting out with a flawed premise, that the needs are somehow different from the other the speakers.
So if you're asking about speakers in general... Yes, the need exists for volume. When you look at sub reviews you see how an eight inch driver may reach 20 Hz, but at really low volumes. You add inches to get more SPL.
Analogously, a 6.5" driver can only put out so many decibels at 100 Hz. As you get closer to reference level, it will fall short, unless it's beefy and able to handle 500 Watts or something.
This is the reason that people who happily crossover their front speakers to subs will still use front drivers of 8, 10, 12 inches, like the eD Cinema, JTR T8, CHT Sho10, and pro speakers.
Likewise, it is why one would use them for center speakers.
Thanks for the info:)
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