frequency of my front speakers is 45HZ-20kHZ so my x-over on receiver is 45?

Discussion in 'Beginners, General Questions' started by Dustin Wind, Sep 6, 2003.

  1. Dustin Wind

    Dustin Wind Stunt Coordinator

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    The frequency of my front speakers(JBL N38II) is 45HZ-20kHZ so my x-over on receiver should be set to 45?

    Also i can do a triple x-over with my Harmon 325 so i can set the x-over on each speaker...

    My center is listed as 80HZ-20kHZ so i should i should set my center x-over to 80?

    Then my backs are listed as 65HZ-20kHZ, so i should set it to 65HZ? on my reciver?

    Is this how it works?
    Then i was reading i set my sub to the highest x-over setting my speakers are....so if i my highest x-over speaker is 80HZ then i set the sub to 80HZ.
    Likewise if a speaker was set to 100HZ then i would set the sub to 100HZ.

    Is this correct?

    Sorry for all the dumb questions, just trying to get the most out of my system.
     
  2. Steve Lucas

    Steve Lucas Stunt Coordinator

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    THX specs say that the sub should have a crossover frequency of 80Hz. That's what I'd use. Also, since none of your speakers play down very low to begin with, I'd set them all to small in the set-up on your receiver. If you must supply a crossover point instead of choosing between large and small speakers, I would use 80Hz for everything. This should make it easier to calibrate and blend your sub in with your other speakers.
     
  3. Ted Lee

    Ted Lee Lead Actor

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    it sounds like you think the lowest frequency your speaker can handle is where you should set your crossover?

    as steve already said, 80Hz is where most people start. in some receivers it's your only choice.

    also, don't forget that the cross-over isn't exactly a "brick-wall". it's not like you can chop off the frequency exactly at 80Hz. so, you should make sure that there is "overlap" between the two ranges. otherwise you'll have a gap where no sound is being reproduced.
     
  4. Cees Alons

    Cees Alons Moderator
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    Dustin,

    If the manufacturer state '45Hz', than that may mean one of several things. Most of the time you wouldn't want to trust speakers even close to that frequency anymore. I'd say rather use 80-90Hz than 75Hz, and certainly not 45Hz.
    As Ted said, the cross-over frequency is where the sound level on both channels is 3db down, so it really extents at least another octave on both (half the figure on the higher channel, twice on the low channel).

    Cees
     
  5. John Garcia

    John Garcia Executive Producer

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    Set your sub to IT'S highest point, so it's x-over does not interfere with the receiver's x-over.

    You can tailor the x-over to each of these speakers, but you as noted, you want to figure on about 1 octave, or a little less, above the speaker's -3dB point (when a response range is given, these should be -3). So for 45hz, you would want roughly 90Hz, and 80Hz will probably work just fine. X-over the center at 100Hz, or as high as you can, and the surrounds also around 100Hz.
     
  6. Dave Poehlman

    Dave Poehlman Producer

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    If you're going with the manufacturer's specs.. generally, the manufacturer skews them in their favor. They'll tell you 45Hz, and your speakers might make some noise at that level, but wont tell you at what dB or if there's any distortion. It's like when you buy a car that says it gets 40 Mpg... that's only if the wind is right and you're going downhill. [​IMG]

    So, as stated above, start with 80Hz. You usually want some "breathing room" between the speakers and sub anyway.
     

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