two center channels??

Discussion in 'Archived Threads 2001-2004' started by JakeMcM, Mar 22, 2003.

  1. JakeMcM

    JakeMcM Stunt Coordinator

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    I was reading a manual for some speakers (Rockets...I don't own them) that recommended two center channel speakers in a front projection system. Well am going to have a 92" diag. screen that will be 45" high. Will there be a benefit to having a centerchannel directly above and below, I guess I should say that it would be a cc-370 with paradigm monitor 7 on the sides. The manual said that it will better lock the dialogue to the larger screen. Are they most likely talking about a screen that would be larger and the centers further apart??

    If this is worth trying would I wire them in series or whatever its called or do I need some sort of seperate amplification.

    Is there a wall mount for center channel speakers??
     
  2. Doug_B

    Doug_B Screenwriter

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    I have the same size screen with my center channel about 2 feet below it and angled up a bit (in line with my ears). Thus far, I have not noticed any problems with dialog anchoring to the screen nor with panning. Truthfully, though, I can't say that I have been focusing on finding such problems. Maybe immersion in the movies is "distracting" such observations a bit, but to me this is the acid test; if there are problems, I'd probably notice them anyway.

    I'm also a proponent of not having speakers against the wall, if at all possible (except subs).

    Doug
     
  3. PaulT

    PaulT Supporting Actor

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    You need to be aware that wiring 2 centres in Series (Amp + to 1st Spkr +, 1st Spkr - to 2nd Spkr +, 2nd Spkr - to Amp -) will give an effect impedance of 16 ohms (for 8 ohm speakers) to the amp.

    On the other hand, wiring in Parallel (All + together, All - together) will give 4 ohms for 2x8 ohm speakers.

    With a 4 ohm load (average) you will get even lower impedance to the amp during certain outputs. This could be a problem with some amps.

    Check to make sure the amp/receiver you use will be able to handle the loads.

    Angling a single speaker as per Doug's post would certainly be the easiest.
     
  4. Rob Rodier

    Rob Rodier Supporting Actor

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    I have always read that 2 centers in not a good idea. Huge 100k systems only use 1, I am not sure why there would be a need for more?
    You woulden't double up the left and right channels...

    In addition, it seems as if the wide dispersion of dialog is not what one is ideally trying to accomplish anyway.

    My advice would be to invest in a single higher quality center speaker.

    However, my info is somewhat dated so maybe something has changed and I am completely wrong.

    -rob
     
  5. Ron_L

    Ron_L Second Unit

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    some people claim that 2 centers give a " roller coaster " type effect with the sound panning.
     
  6. Rob Rodier

    Rob Rodier Supporting Actor

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  7. PaulT

    PaulT Supporting Actor

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    What Rob is refering to is if the sound pans from left to right (for example) through the centre channel, if you have a stacked pair (above and below the screen) of centres, the sound would appear to your ears to move like a roller coaster rather than a straight pan left to right across the sound-stage.
     
  8. JakeMcM

    JakeMcM Stunt Coordinator

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    I see, its cheaper and easier to keep just using one with more benefit, thanks for the input.
     
  9. Robert McClanahan

    Robert McClanahan Stunt Coordinator

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    The most important speaker in any home theater is the center channel.I might agree that two centers for a large screen would make sense.The bigger the screen the larger the area of dialogue to be covered.It may sound weird but its about eye and ear coordination.Imagine a huge center channel with a small t.v..It does not work in my opinion.[​IMG]
     
  10. RichardHOS

    RichardHOS Second Unit

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    From other similar questions posted on forums, the general concensus (including input from well respected professionals) is that it is a 'bad idea.'

    I think the reason is primarily that two speakers playing exactly the same signal will be very susceptible to comb filtering effects and destructive interference.

    With left and right channels, the information is not precisely the same, and when it is the interference pattern is intentional. With a "dual center" it would not be. Also something about having two ears left and right instead of "top and bottom" was brought up on several occasions, with some comments about not being able to properly combine two sources vertically separated.

    I know line arrays and ribbon tweeters (long ones) suffer from comb filtering effects, so I'm not sure what makes the two centers that much worse. Perhaps because they are two point sources and not a continuous vertical line source.

    Just passing on some gathered comments on this topic...
     

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