Traditional Center vs. Bookshelf on it's side

Discussion in 'Speakers' started by Greg_Ritchie, Aug 7, 2003.

  1. Greg_Ritchie

    Greg_Ritchie Stunt Coordinator

    Aug 10, 2002
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    Not being all that knowledgable about acoustics I'm wondering what the benefit of a traditional center speaker is? Currently I have a JBL N28 on top of my RPTV as a center and I'm pretty happy with it at the moment. Why go with a normal center instead of a bookshelf? I figure there must be a benefit from having the tweeter in the center and the woofers on both ends of the speaker. Does it have better dispersion? And if I'm sitting dead center does dispersion really matter?

  2. Lew Crippen

    Lew Crippen Executive Producer

    May 19, 2002
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    Short answer: if you are happy, don’t change.

    Slightly longer answer: Dolby recommends that all five speakers be the same, so if your other speakers are JBL N28s you are in line with Dolby recommendations.

    Long (and rambling) answer:

    Even though Dolby recommends that all the speakers be the same, there are plenty of valid reasons to deviate from that recommendation. One reason is esthetics. Since many center speakers are placed just below or just above a TV that is likely generally wider than tall or at least mostly square, a horizontal look fits in better with our sense of proportion. Even were that not the case floor-standing speakers could either block the view of the display or place the tweeters well above optimal listening levels.

    Most non-center speakers are not shielded, meaning that a common center speaker placement (on top of the TV) can result in discoloration of the display by the magnets of the center speaker. Most manufacturers shield the magnets of their center speaker drivers—though not all do for the tweeters.

    Most HT mixes place most of the dialogue in the center channel. Many center speakers are designed with this in mind, often including a separate mid-range driver (in addition to a tweeter and a woofer or two). A typical crossover would then be at 400hz or 500hz and maybe 4,000hz, which allows most speech to be directed to a purpose built driver. In theory this might mean that it would be easier to distinguish speech.

    In any case a good many packages, including the less expensive ones, now make their very best speaker the center speaker, because it is the most important (in 5.1 movie mixes). A very good example of this is the Acoustic Research HC6 package, which can be found for less than $400.

    There are some audio experts who can distinguish problems with the dispersion issues you mention, but this is (imo) quite esoteric. And in any case one of the critiqued alignments is MTM (mid/tweeter/mid) model, which is what many center speakers provide—the mids are mid/woofers in this config.

    A very long way of saying, if you are happy, stay with what you have.
  3. Torgny Nilsson

    Torgny Nilsson Second Unit

    Jan 8, 2003
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    I second the response of using the same speaker for a center that you are using for your other speakers. I have tried "center" speakers and I don't think they give you as good an effect. This assumes, of course, that you are using good speakers. If you go with a cheap speaker system, then it may be that a special center speaker is better.
  4. Steve_D

    Steve_D Second Unit

    Nov 28, 1999
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    I use a "regular" speaker for a center, and through 2 rounds of speaker upgrades. No problem in doing so...except maybe magnetic current center channel is a shielded "bookshelf".

    FYI, many designed center channels have inherent problems in their horizontal on-axis W-T-W design at least as serious to the audiophile as laying a traditional speaker on its side.

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