Subwoofer that will accept passive speaker-level inputs? Does such a thing exist??

Discussion in 'Speakers' started by KyleT, Sep 13, 2004.

  1. KyleT

    KyleT Stunt Coordinator

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    To summarize my setup in short: I have a whole-house audio system setup. I have a big dedicated 2-channel amp (Rotel 1090) in my wiring closet going to a distribution block. From there 8 pairs of speaker cables go throughout the house to volume control switches (100 watts RMS max per channel per pair). So in the end I have whatever pair of speakers connected directly to the wall where they directly fed power that is moderated by my volume switch.

    To summarize what I want in short: For parties and such, I'd like to get a little more bass output from the speakers in the 'party' area of my house. They already have 8" drivers built in, and produce moderate and very clean bass, but being in a large open area, they just don't put out bass I can feel.

    And the problem is: I have no way of getting a dedicated preamp signal to a sub in this area of the house... especially not one that is synchronized with what the amp is playing upstairs in my wiring closet.

    So my question is: Are there any subwoofers out there that are capable of taking a full-powered audio signal that is destined for a speaker (or pair of speakers), mooch off just enough power to get a satisfactory "preamp" feed, and then pass the power along to the speakers themselves, all without making any noticable difference in the sound quality of the sub and/or the speaker(s)?
     
  2. BrianWoerndle

    BrianWoerndle Supporting Actor

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    Almost all subs have that and it is usually called High level speaker inputs.
     
  3. KyleT

    KyleT Stunt Coordinator

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    So they will not only get a good clean signal from the speaker cable, but will go on ahead and pass it along to the speakers with no problem?[​IMG]
     
  4. KyleT

    KyleT Stunt Coordinator

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    I don't have the choice to run seperate cables. So which would sound best and would it even be worth it at all considering the potential loss of sound quality? Splice into one of the channel's cables and run it to the sub, or run the entire cable from one or both channels through the sub?
     
  5. Edward J M

    Edward J M Cinematographer

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    Yes, some HPF's can degrade the signal, but for a party application (where absolute fidelity isn't the first priority) I certainly wouldn't sweat it.

    Some of the Velo's come with a defeat switch for the high pass filter (so the speaker gets a full range signal). If the HPF is enabled, it's usually at 80-100 Hz, with a 1st or 2nd order slope.

    Even if the speaker gets a full range signal, you're just looking to add more bass for parties anyway, so overlapping the sub with the mains on full range shouldn't be that big of a deal, particularly if you set the low pass filter on the sub somewhere in the 50-60 Hz region (where the mains are probably starting to fade in a bigger room anyway).

    Clear as mud, right?
     
  6. Wayne A. Pflughaupt

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    For this application that’s the way I’d do it: Spice into the speaker wires. That way the sub can get it’s input signal, but the main speakers don’t see the sub’s high pass filter. Sure the mains will still be getting a full-range signal, but as Ed noted it shouldn’t be hard to blend in the sub with it’s variable crossover capabilities.

    Regards,
    Wayne A. Pflughaupt
     
  7. Dr. Anthony Rosalia

    Dr. Anthony Rosalia Stunt Coordinator

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    An addendum to Jack's post:

    Make sure you get the polarity correct when you splice into both sets of wires. If you reverse one set (+/-) you may damage your speakers, the sub and the sub amp. Putting two sets of line levels into your sub in inversed phase will dramatically reduce your subs output as most base is monophonic and cause havoc in the rest of the system. The bass will cancel itself out.

    Rule of thumb: + to + - to - always. I say this just to prevent a costly mistake not to insinuate you don't know + from - [​IMG].
     

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