wiring rear center in a 6.1 setup

Discussion in 'Speakers & Subwoofers' started by RogerA, Jul 8, 2004.

  1. RogerA

    RogerA Extra

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    I just bought a cheap reciever (Panasonic sa xr25) 100.00 that has 6.1 capability. I just won an auction on ebay for 2 jbl n24 speakers and was wondering if I could or should hook them both up as center rear. My other sat speakers are also n24's.

    If I do hook them both up, how would I wire them together.
     
  2. Ray Tsui

    Ray Tsui Stunt Coordinator

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    you would basically wire both speakers to the same terminals, but that's going to be a very tough load for your receiver since it's going to drop the impedance in half.

    I wouldn't recommend doing it at all, you would be placing undue strain on the receiver because it's not designed to have two speakers connected to the same terminal.
     
  3. Wayne A. Pflughaupt

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    I must say I don’t get this “thing” people have that about this, “I only needed one speaker but I ended up with two, I feel like it’s a waste not to use them both.”

    Does anyone use all the inputs on their receiver? Hardly, but no one feels like anything’s being wasted if they don’t. Or VCRs. Did anyone, anywhere, ever use all the features those things have?? Ever see anyone wringing their hands over that?

    Just use the one speaker, Roger. I promise it won’t be the end of the world if the other one sits in the closet. [​IMG]

    Besides, if you ever want to get rid of them, you’ll be happy you have the pair. It’s hard to find buyers for a single speaker.

    Regards,
    Wayne A. Pflughaupt
     
  4. RogerA

    RogerA Extra

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    Thanks for the replies.

    I've always lived by the creedo, "if one is good then 2 is better". Honestly though, I can hardly tell the difference when the rear center is on anyway unless I have my ear right up to it when that channel happens to have some activity during the play back of a DVD.

    I'm sure it fills that void between the two R & L surrounds with sound and how did we ever survive without it.

    So I will use only the one speaker and hope that the world doesn't come to a tragic end because of my willful act of waste.

    Which reminds me, I need to get some more components for my HT system. I still have about 6 inputs to fill on my receiver[​IMG]
     
  5. RogerA

    RogerA Extra

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    I forgot to add that I am going to have to ceiling mount this rear center because of logistics of the room. Will it be effective there? Standard 8 ft ceiling.

    If I had to, I probably could put it on a speaker stand if you think that would be better. Room dimensions are 26x16.
     
  6. Aaron Howell

    Aaron Howell Stunt Coordinator

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    Or you could find someone else who is looking for a single n24ii. Like me! What condition is it in? Any pics? How much shipped to 48346? [​IMG] Maybe I'm getting ahead of myself..oh well.
     
  7. Darren_N

    Darren_N Stunt Coordinator

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    Hello all,

    Like Roger, I'm also considering mounting some N24's on the ceiling for my rear surrounds because it would be the best solution due to room layout. However, in the manual for the N24, it states that they are not intended for ceiling mounting. Has anyone tried this with these speakers? Does JBL warn against it because it would affect the sound in some way or is it just because the hardware that comes with the speakers can't be used as a ceiling mount?

    Any opinions? Anyone have first hand knowledge? Thanks in advance.

    Darren
     
  8. Wayne A. Pflughaupt

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    I would assume the latter, as they would be more concerned about safety isses, or physical damage to the cabinet.
     
  9. Phil Iturralde

    Phil Iturralde Screenwriter

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  10. Jonathan Dagmar

    Jonathan Dagmar Supporting Actor

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    `for $100 you have just bought a superb reciever that can compete with other costing 700-800 dollars. It's an old model, so it has been marked down a lot.

    I don't really agree with Dolby's advice here, because it's incomplete. Unless you have a very big wide room, there is absolutly NO REASON to use two speakers for your rear center. Just use one and avoid putting extra load on your receiever, it's not designed for that and it would be a bad idea IMO. Also you mention it is going to be tricky for you to place the rear speaker, why make it even harder on yourself by having to place two of them.

    Once you start getting into using multipe speaker for one channel, you may as well do the same thing for your left and right surrounds too, as is done in the commercial cinema. But for most of use our rooms simply aren't big enough for there to be any benefit to this.

    You can wire them series, as phil describes, but it's probably not necessary, unless, as I say, your back wall and distance between left an right surrounds is really wide. (20+ feet)
     
  11. David Judah

    David Judah Screenwriter

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    I have an XR25 and am running my two back surrounds in-parallel for a 4 ohm load(all the rest are 8). I haven't had any problems even at high levels, so it's definietly no problem at the normal levels I listen at.

    It might not work well with some speakers, but it works with mine, and with no deleterious effects that I've encountered.

    DJ
     
  12. Jonathan Dagmar

    Jonathan Dagmar Supporting Actor

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    it's good that that works for you, but the XR25 is not rated for use with speaker rater lower than 6ohms.

    I don't think what you are doing is very wise...
     
  13. Phil Iturralde

    Phil Iturralde Screenwriter

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    This quick Watts vs. SPL chart shows why ...
    Watt(s)..SPL(dB)
    1w............86 (N24s rating)
    2w............89
    4w............92
    8w............95
    16w..........98
    32w.........101
    64w.........104 (Dolby Digital Home Theater SPL Levels)
    128w.......107
    256w.......110

    If you just mount one JBL N24 then, ... never mind!

    Phil
     
  14. David Judah

    David Judah Screenwriter

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    If you've read some of the threads on the different forums, Jonathan, it's not so much 4 ohm speakers, in general, that give the Panasonics trouble, but one's that have impedance curves that fluctuates drastically.

    There are plenty of users using 4 ohm speakers of reasonable sensitivity with no ill effects. Of course, common sense dictates that one should be careful in such set-ups. In addition, although I don't know from experience, the TI digital solution used in the XR series is supposed to clip more gracefully than traditional SS amps(they are more like tube amps in that regard).

    DJ
     
  15. ChrisWiggles

    ChrisWiggles Producer

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    Well, there *are* legitimate reasons for using dual rear centers, and it's why Dolby, THX, DTS, Lexicon, etc all advocate using a 7.1 setup and *not* a 6.1 setup, even if those dual rears are in mono (as in this case, and as in my setup). The reason has little to do with the size of the room, and everything to do with psychoacoustics. Placing a single speaker exactly on-axis behind your head is the hardest place to image right, and your brain can and will confuse sounds imaged hard there as coming from in front of you, the "reversal" effect. This is very much undesired.

    Hence, I disagree with Wayne on this one, while I see often people want to "take advantage" of everything they buy by turning it up really loud (subs for instance), here is a case where more *is* preferred, and for good reason. Lexicon, for instance, does not even support 6.1 setups with L7 to my knowledge. I recommend using a 7.1 array wherever possible, in accordance with pretty much every big-name audio company out there.
     
  16. Jonathan Dagmar

    Jonathan Dagmar Supporting Actor

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    On the other hand, if you have reasonably good speakers, they can and should put out a fairly diffuse soundfield, so, so long as the speaker is 5ft or more away from the back of your head, the cancelling effect will most likely be minimized.

    Perhaps a dipole would also work nicely for the rear center if you only wanted one speaker.

    For me using two speaker for the rear center is simply impractical. I did try it, as the booksheld speaker i bought only came in pairs, wired in series as was suggested to me a long time ago, and i spent a good couple of hours comparing 1 speaker to two. I really could not notice any difference,if anything it made the rear blend more with the sides to the point of being redundent, and therefore I removed the second speaker.

    I still belive whether you need one speaker or two is determined by the room. My room is small, about 10X17, and the rear speaker is on a short wall.
     
  17. Jonathan Dagmar

    Jonathan Dagmar Supporting Actor

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    I actually think ceiling mounting the RC might be a *good* thing as it would offer a more diffuse sound that might prevent you brain being tricked into hearing the sound as if it were in front of you (which i have not found to be an issue with me anyway...)
     
  18. ChrisWiggles

    ChrisWiggles Producer

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    Although others have mistakenly thought that this was the reason for going dual backs, this is totally wrong. It has nothing to do with cancellation with the fronts, and everything to do with the behind the head on-axis placement of a speaker. Mono-pole speakers will image very well, as you well know from the placement of main speakers if you're experimented with this in the past. Bipole/dipole/omnipole, etc will be much more diffuse, and will likely minimize any reversal phenomenon.

    However, your beleifs are an aside, and there are concrete reasons behind the recommendations for 7.1 arrays, that are not so easily discarded by half-way logic...
     
  19. RogerA

    RogerA Extra

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    Phil Iturralde, I have read a lot of your previous threads and reviews and checked out your homepage as well (very impressive) and I know you are a big JBL fan as am I. I have an all Northridge setup with the fronts ND310's, N-center and the surrounds are N24's and now the back centers will be N24's. I even have JBL subs, a PB12 and an Infinity PS12. They do the job for me and I am very happy with the way they sound. Thanks for the great information in this thread, I would really prefer a 2 center back arrangement, my only concern would it be harmful to my receiver? Even wired in series as you have suggested.


    Jonathan Dagmar, you are right about the sa xr25. It sounds better to me with my room and components than a Yamaha 980W I demoed in my home. That receiver retails for around $800.00. I was skeptical when I bought the sa xr25 because of the low price (it was a floor model) and the weight (around 8 lbs) but I am very happy with the performance I get from it. I wasn't even looking for a receiver when I saw this one for sale but could't resist at least trying it for such a low price.
     

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