Setting up seperate sub w/full range speakers?

Discussion in 'Speakers & Subwoofers' started by Andrew Pezzo, Jun 30, 2003.

  1. Andrew Pezzo

    Andrew Pezzo Second Unit

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    Was wondering how to set up a seperate sub when using full range speakers for the front L/R and center (ones with built-in powered subs). My front 3 speakers are rated to 19Hz (probably more like low 20's though). The sub I am looking at is rated to 14 Hz.

    When adding a sub how should I set my receiver settings? If I choose small for the fronts (currently have it to large since I dont have seperate sub at this point) wont I be losing the benefits of the built-in subs? Should I lower the crossover setting on my receiver?

    This is rather confusing becasue I dont want to waste the full range abilities of my speakers but would like to add some extra impact for movies. Any suggestions?

    My setup:
    Denon AVR3803
    Front L/R Def Tech BP2006TL
    Center Def Tech CLR2300
    Surrounds Def Tech BP2X
     
  2. Lew Crippen

    Lew Crippen Executive Producer

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    If you set all speakers to large, your sub will only be used for the Low Frequency Effects (LFE) channel (or the .1 in the 5.1 system). Which means that the sub will get only the signals in the .1 trrack, while the main speakers will get the full frequencies of their channels.

    For any speakers set to ‘small’, the sub should get both the LFE information and all of the frequencies below the chosen cutoff point.

    Of course this concept can be defeated by placing the sub on the same set of outputs as the mains. The above assumes that the sub is connected directly to the receiver.

    I would suggest setting your surrounds to ‘small’ regardless of how you decide to set your front spearers.

    Just experiment and see what you like best.
     
  3. Andrew Pezzo

    Andrew Pezzo Second Unit

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  4. JohnRice

    JohnRice Lead Actor

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    Andrew, I would leave the surrounds on small. Don't worry too much about missing bass from them.


    I would hook up the sub to the sub output and just experiment with the setting of the fronts, though I would be inclined to leave the center on small regardless. If it is sitting on top of the TV, it will just reverberate in the cabinet anyway. The "subs" on your mains are probably really just powered woofers. I seriously doubt they have any genuine, usable output down to 19Hz. check the manual and see what their crossover frequency is. It is probably a few hundred Hz, which makes them absolutely fine to be run on small. Remember, the crossover out of your receiver is probably about 85Hz, so there is plenty of room in between. Definitive makes nice speakers, but they are notorious (as most manufacturers are) for grossly overstating the low end of their speakers, so leave the real bass to the dedicated sub.
     
  5. Paul.Little

    Paul.Little Stunt Coordinator

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    Andrew,
    I have a pair of bookshelf speakers for my mains (B&W DM601) and I set them to large. By all means, set your main and center (you did say you had a powered woofer in your center, as well?) to large, and set the receiver's cross-over as low as it will go. It should sound great!

    Paul
     
  6. Greg Bright

    Greg Bright Second Unit

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    Paul,
    Does that mean that none of the really low bass being directed to you front mains is being heard at all, since it isn't being re-directed to the sub? Or does your receiver have some sort of compensation circuitry that allows bass being sent to the mains to also be sent to the sub? If (a) then it seems to me that you are depriving yourself of your home theater birthright - full bass from any and all channels!

    Greg
     
  7. JohnRice

    JohnRice Lead Actor

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    Greg, yes that is basically it. I understand people wanting to pump every ounce out of everything they have, but when you set bookshelf speakers to large, the bass for their channel is routed to them. If you set them to small, they get a breather by being relieved of the draining bass frequencies, which generally makes them cleaner sounding and the bass is sent to the sub, which is most capable of reproducing it. You also reduce the chance of the various speakers cancelling each other's low frequencies out.

    Now, some processors do have another sub mode that routes the low frequencies to the sub as well, even when other speakers are set to large. The cancellation issue still exists.

    I have Thiel CS 3.6s, which are quite large, expensive and extremely solidly built speakers with very low frequency response, and I still don't feed them the full range. They do sound better that way.

    I also notice that when it comes to bass, many folks like a constant thudding, which I hate. One benefit of isolating most of the low frequencies to the sub is that it can help the sound explode when it is supposed to, and be more subtle other times.
     

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