Crossover on sub or amp??

Discussion in 'Speakers & Subwoofers' started by BrettisMckinney, Apr 10, 2003.

  1. BrettisMckinney

    BrettisMckinney Second Unit

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    I never thought about it much before but after doing some reading i think im a bit confused.
    I've set all my speakers to small and i have a manual crossover on my sub that i set at around 80-85. Now i hear that if the amp has a sub crossover at 85 then that is all that will be sent to the sub..but if i turn my x-over on the sub up..it definately works..it gets boomy and higher.

    So what am i to do?
     
  2. Nater

    Nater Extra

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    Set the X-over that you want on your amp. Then set the sub's higher than that so that you make sure it "receives" everything that the amp "sends". If you don't like it sounding boomy and higher then adjust the setting on the amp, and keep the sub's setting higher.
     
  3. HowardGjr

    HowardGjr Stunt Coordinator

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    Bettis,

    By turning the crossover on the sub up, you are effectively "disabling it" and only using the crossover in the receiver. Your sub will handle all frequencies under 80 Hz.

    FWIW...the crossover it the receiver is digital and the one in the sub most likely is analog.

    After your happy with your subs crossover, make sure you take the time to recalibrate the system. Hopefully, that will reduce the "boomy" character of your bass. If it doesn't and the the bass performance bothers you, plan to spend a lot of time chasing down room effects.

    Take care
    Howard
     
  4. BrettisMckinney

    BrettisMckinney Second Unit

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    THanks for your help guys. I cant change the crossover on the amp though so im not sure what it automatically sets it at? I just keep my sub at around 85, but i do know that if i turn it up then it goes up and gets boomy.
     
  5. PaulDF

    PaulDF Second Unit

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    A crossover does not act as a brick wall. The lower frequencies being sent to the subwoofer are gradually decreasing, just as the higher frequencies being sent to your other speakers are gradually increasing... The rate at which the levels rise or fall depends on what types of filters are used. (I have found its not as steep a slope as I used to think!). If you saw this on a line graph, the sub response line and the main speaker response line would cross each other (hence the name crossover). Hopefully with as smooth and level a transition as posible.

    It might help to find out what your receiver's crossover setting actually is. Typically leaving the sub amp's crossover set as high as possible leaves you with the best transition. (Assuming your receiver performs the crossover duty properly). If you are still not happy with it, then you'll need to pick up an SPL meter to make some measurements. This way you can use your Sound Pressure Level meter along with some 20 to 200 hz tones to measure your frequency response throughout the crossover transition. This is an accurate way to make sure all is well and that there are no missing frequencies, or exagerated frequencies (booming).

    There are also excellent setup DVDs out there to use along with an SPL meter to get the most out of your system. These discs have many different tests to setup everything you need to. I have AVIA and Sound & Vision Home Theater Tuneup. They are both well worth the money.
     
  6. BrettisMckinney

    BrettisMckinney Second Unit

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    I've got the Ultimate DVD platinum and it does have some test tones so i'll play with that. I'll definately check what my amps crossover is set at. For music though, you couldnt leave you subs crossover at full could you? Thats just asking for boominess!
     
  7. PaulDF

    PaulDF Second Unit

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    If your receiver is doing the crossover funtion properly, there should be no dips or peaks in the frequency response during the crossover from mains to sub...

    Also, other issues come into play too, such as phase, and room effects. This is where the SPL meter will come in handy. It'll tell you the numbers so you know for sure whats going on.
     

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