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  1. #1
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    Bi-amping the center channel?

    This is my first post to audioreview though I have been a long time visitor. Best website regarding home theater!

    My question is regarding my Polk CSi5 center speaker. It has the ability to bi-amp, though I am unable to find any receivers that have such an ability. I currently own the Denon 2807 which has a/b for the front left/right. A specific model of Marantz has caught my eye, the 8500. I noticed on the back it has what they call a "Multi-Speaker 'C' Output". Would this receiver have the ability to switch from Surround Back (as labeled below the banana plugs) to a bi-amped center channel connection?

    I'm also deciding if I should purchase seperates instead. I'm not very familiar with pre-amps, do they provide the ability to split a center channel into high and low frequencies for a bi-amped connection? I could very much bi-wire the connection, but I own a 200w max rated speaker; I'd like to use it to its fullest capabilities.

    To those of you with much more experience, i'd like to hear your opinions and help me decide which road I should take.

  2. #2
    Color me gone... Resident Loser's Avatar
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    I may be wrong...

    ...and since I don't subscribe to the laser-totin' mechanical lizardry of HT, isn't the center channel supposed to be matrixed or steered to provide mostly a fixed point for a film's dialog? If that's the case, and since the human voice has a rather narrow frequency response, I can see no reason to bi-amp or bi-wire...in fact don't most center channel speakers contain basically mid-range drivers or at least restrict their FR to freqs within that range?

    jimHJJ(...but that's just an un-educated, questioning guess...)
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  3. #3
    Suspended PeruvianSkies's Avatar
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    You could bi-amp it with two amps, but I doubt that you are really going to get much advantage as for reasons that Resident Loser already mentioned. If you are going to bi-amp anything I would do your left and right speakers and let your center channel be.

  4. #4
    Suspended topspeed's Avatar
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    Save your money. You could bi-amp your cc, but why? In particular, why bother with bi-amping with the same amps in an AVR? Each channel in your standard AVR shares the same power supply, the same transformer. Therefore, all you are doing is increasing the stress to the power supply. Does this sound conducive to better sound?

    The only time I would consider bi-amping is if I was using two distinctly different amps such as a ss amp for the bass and a tube for the highs.

    I own a 200w max rated speaker; I'd like to use it to its fullest capabilities.
    Forget this number. Unless your listening room is inordinately large or you're deaf, most of the time you're only using a few watts. Truth. Consider that most modern speakers are rated for ~ 90dB/w/m. This means for 1 watt they are producing 90dB's of sound pressure measured 1 meter from the speaker. 90dB's is pretty freakin' loud! Max wattage ratings are for marketing, nothing more.

    Hope this helps.

  5. #5
    Crackhead Extraordinaire Dusty Chalk's Avatar
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    I agree with the above opinion. The center channel should be the last speaker you bi-amp, as it usually has very little low frequency information. Well, maybe the surrounds. But if you're going to biamp anything, biamp your front left and right speakers first.

    Oh, and usually, when we're talking about stereo, we say preamp, and when we're talking about HT, we say prepro (short for preprocessor), as the latter does more than just simply act like a multi-channel preamp (decodes Dolby and DTS, nominal bass management, multi-channel speaker setup, etc.).
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  6. #6
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    Thanks for the replies guys. the CSi5 gives the opportunity to seperate its two woofers from its tweeter. as you mentioned, the center speaker is mainly used for dialog. which is why i'd like to have each driver have its own dedicated power. im not worried much about the woofers having enough power, but i dont want them to take away from the power the tweeter needs during an intense scene (honestly I do notice some issues on my THX demos). I already have my RTi8's bi-amped and there was a world of difference. I seriously doubt Polk would go through all the trouble of adding two crossover networks if it wasnt nessicary, there has to be some sort of performance gain.

  7. #7
    Crackhead Extraordinaire Dusty Chalk's Avatar
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    Oh, well then, by all means, do it. How are you biamping your RTi8's? I would do it the same way, if you still can. Perhaps a monoblock, fed from your (center channel) pre out?
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  8. #8
    Forum Regular Woochifer's Avatar
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    Quote Originally Posted by Resident Loser
    ...and since I don't subscribe to the laser-totin' mechanical lizardry of HT, isn't the center channel supposed to be matrixed or steered to provide mostly a fixed point for a film's dialog? If that's the case, and since the human voice has a rather narrow frequency response, I can see no reason to bi-amp or bi-wire...in fact don't most center channel speakers contain basically mid-range drivers or at least restrict their FR to freqs within that range?

    jimHJJ(...but that's just an un-educated, questioning guess...)
    The role of the center speaker heavily depends on how the original mix was done. For movies, most of them are mixed with the dialog anchored to the center. But, you do have exceptions where the imaging of the dialog is panned more actively across the front soundstage. Soundtracks for concert DVDs or multichannel music do not limit the frequency range for the material that gets mixed into the center channel.

    In general, the center speakers will use the same (or at least comparably voiced) drivers as the mains, which means that they would have comparable frequency range as well. Their only deficiency would likely be in the lower frequencies simply because their design limits the amount of internal volume that the cabinetry can have. But, if the bass management redirects the bass through the subwoofer or through the main speakers as with most 5.1 setups, the bass limitations with the center are inconsequential.

    The general rule of thumb with center speakers is that need to voice match the mains as closely as possible. This means that they generally perform the same as a main speaker from about 60 Hz all the way up into the highs.
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  9. #9
    Forum Regular Woochifer's Avatar
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    Quote Originally Posted by tehxeer
    This is my first post to audioreview though I have been a long time visitor. Best website regarding home theater!

    My question is regarding my Polk CSi5 center speaker. It has the ability to bi-amp, though I am unable to find any receivers that have such an ability. I currently own the Denon 2807 which has a/b for the front left/right. A specific model of Marantz has caught my eye, the 8500. I noticed on the back it has what they call a "Multi-Speaker 'C' Output". Would this receiver have the ability to switch from Surround Back (as labeled below the banana plugs) to a bi-amped center channel connection?
    Just because a speaker has two sets of binding posts does not mean that you have to make use of that capability, or that it would even make a consequential difference to begin with.

    Focus your efforts on properly positioning and calibrating your system first. Level matching the speakers with a SPL meter, and aligning the speakers for optimal imaging will go much further towards improving your system performance and won't cost you nearly as much. Only after you've optimized your setup should you even think about amplification and/or cabling upgrades.

    Of all the channels to bi-amp, I would look to the mains first and even then, IMO it's a futile exercise with a receiver for the reasons that topspeed mentioned.

    Quote Originally Posted by tehxeer
    I'm also deciding if I should purchase seperates instead. I'm not very familiar with pre-amps, do they provide the ability to split a center channel into high and low frequencies for a bi-amped connection? I could very much bi-wire the connection, but I own a 200w max rated speaker; I'd like to use it to its fullest capabilities.
    Geez, your receiver is less than a year old! Use it and enjoy it for a while, and get to know all those features and functions that you probably haven't tried yet. With your receiver, you could always just add an outboard amplifier. But, in all likelihood you got other things, such as the speaker alignment, speaker level matching, and room acoustics, that you could work on before taking that step.

    No need to split the frequencies when biamping. You just remove the metal jumpers that connect the two sets of binding posts, and the internal crossovers on the speaker will filter out whatever signal content is not supposed to make its way to the drivers.

    Make note that the center speaker is rated for 200 watts MAX. Your ears will start hurting way before the amp even comes close to 200 watts of output to that channel.
    Wooch's Home Theater 2.0 (Pics)
    Panasonic VIERA TH-C50FD18 50" 1080p
    Paradigm Reference Studio 40, CC, and 20 v.2
    Adire Audio Rava (EQ: Behringer Feedback Destroyer DSP1124)
    Yamaha RX-A1030
    Dual CS5000 (Ortofon OM30 Super)
    Sony UBP-X800
    Sony Playstation 3 (MediaLink OS X Server)
    Sony ES SCD-C2000ES
    JVC HR-S3912U
    Directv HR44 and WVB
    Logitech Harmony 700
    iPhone 5s/iPad 3
    Linksys WES610



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  10. #10
    Forum Regular Woochifer's Avatar
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    Quote Originally Posted by tehxeer
    Thanks for the replies guys. the CSi5 gives the opportunity to seperate its two woofers from its tweeter. as you mentioned, the center speaker is mainly used for dialog. which is why i'd like to have each driver have its own dedicated power. im not worried much about the woofers having enough power, but i dont want them to take away from the power the tweeter needs during an intense scene (honestly I do notice some issues on my THX demos). I already have my RTi8's bi-amped and there was a world of difference. I seriously doubt Polk would go through all the trouble of adding two crossover networks if it wasnt nessicary, there has to be some sort of performance gain.
    The center speaker is not going to draw enough output to ever warrant needing separate amps for each driver. How are you so sure that you'll ever get a power deficiency in your center speaker?

    The rationale behind biamping is often to "warm up" or otherwise refine the sound by using different amp designs for each set of drivers, such as going with a tube amp on the tweeter and a SS amp for the woofers. If you use the same amp for both sets of drivers, then it makes minimal difference compared to other changes that you could make to your system.

    Don't be so sure that there's a performance gain just because a speaker manufacturer splits out the crossover onto two sets of binding posts. Very often, the marketing department has more of a say in what goes into the speakers. Some manufacturers such as Dynaudio and Dunlavy never put dual binding posts onto their speakers because they never believed that biamping or biwiring provides any benefit. Others such as Klipsch and (I believe) McIntosh only included dual binding posts because they did not want to lose any sales. But, all the while, their engineers at some point have said that biwiring and biamping are a waste of money.
    Wooch's Home Theater 2.0 (Pics)
    Panasonic VIERA TH-C50FD18 50" 1080p
    Paradigm Reference Studio 40, CC, and 20 v.2
    Adire Audio Rava (EQ: Behringer Feedback Destroyer DSP1124)
    Yamaha RX-A1030
    Dual CS5000 (Ortofon OM30 Super)
    Sony UBP-X800
    Sony Playstation 3 (MediaLink OS X Server)
    Sony ES SCD-C2000ES
    JVC HR-S3912U
    Directv HR44 and WVB
    Logitech Harmony 700
    iPhone 5s/iPad 3
    Linksys WES610



    The Neverending DVD/BD Collection

    Subwoofer Setup and Parametric EQ Results *Dead Link*

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