What is the LFE's crossover set at?

Discussion in 'Speakers & Subwoofers' started by Christopher_Ham, Oct 7, 2003.

  1. Christopher_Ham

    Christopher_Ham Stunt Coordinator

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    I am running DEF TECH bp8's and a CLR 2002 up front and a set of bp2x's for the sides. I have the whole system set on full range. My fronts are all rated in 22-28 hz range and my rears are 45 hz. Should I turn off my subs crossover and just let the full LFE channel come in, I assume the DD and DTS standard is 80hz, is that right? Or should I set the subs crossover to approx 50 hz, about 5 hz above my bpx2's limits.
     
  2. Lew Crippen

    Lew Crippen Executive Producer

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    A couple of assumptions on your configuration: you have a discreet sub and that this sub is not wired in front of your mains, and is being driven from the sub output on your receiver.

    Under these assumptions, turn off you subs crossover. With all of your speaker set to large, your receiver will only be sending LFE sound to the sub. This also means that your sub is receiving no sound which should be reproduced on any of the other speakers (the receiver only sends some of the sound to the sub when a speaker is set to ‘small’. So the sub should is not asked to reproduce any sounds that are not in its range and none of the sounds being sent to it are being sent anywhere else.

    Therefore if you set a limit on your sub by setting the crossover, you may be missing sound.
     
  3. Christopher_Ham

    Christopher_Ham Stunt Coordinator

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    I am running a Lexicon DC-1 and an ATI 1505 amp. I am only using the sub out. I am running 2 subs, and SVS for LFE and an Atlantic TECh t70.b. The AT sub is used to help my center channel. The center is hooked up to its own sub via an rca split right out of the processor and then set a the same bass out put as the L and R passive speakers, about 75 db's. I set the crossover at about 55 even though the center can go down to about 25 hz( it may go that low, but it does not put out many db's on its own, that is why I am supplementing it with the sub. Should I also run the rears through my extra sub as to get all my speakers to the same bass db output as my mains, and then continue using the SVS as the LFE channel?
     
  4. Lew Crippen

    Lew Crippen Executive Producer

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    If you want to continue with the two sub configuration, don’t use the SVS crossover (this is already covered), as it will only be getting the LFE channel and that channel won’t be anywhere else.

    I don’t know anything about the Atlantic Tech sub, so you need to take this advice with a grain of salt.

    If you believe that there are some low frequencies present in the center channel that your particular center channel won’t reproduce you might consider setting the center channel to small and the receiver crossover to (maybe 80 Hz). This will send center channel frequencies from 20 Hz–~150 Hz to the SVS (the amount decreases above 80 Hz) and from 40 Hz (or so) up to the center channel (the amount decreases below 80 Hz). This ought to allow good reproduction of both the LFE and low frequency center channel by the SVS and at the same time, not asking your center to go beyond its capabilities.

    If you feel that the SVS alone does not have enough SPL, you can add the AT sub to also handle the LFE plus low frequency center channel sound reproduction.

    I would try the same thing with the surround channels. In fact I would try the surrounds first, as they don’t go as low as the center.

    This may not work in your room, but you might want to give it a try and see how you like the results. You may need to experiment a bit with the correct crossover setting and especially the placement of the two subs.
     

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