Subwoofer wiring

Discussion in 'Speakers' started by Erik.Ha, Mar 12, 2004.

  1. Erik.Ha

    Erik.Ha Supporting Actor

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    Is there any advantage/disadvantage to splitting the RCA to a sub and plugging it into BOTH (L/R) RCA inputs?
     
  2. Alex_P

    Alex_P Stunt Coordinator

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    plugging both L/R inputs will give you 3db louder...
     
  3. Erik.Ha

    Erik.Ha Supporting Actor

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    Why 3Db? My intuition (which I trust is wrong) tells me it should be "double or nothing"???
     
  4. GrahamT

    GrahamT Supporting Actor

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    3dB is double
     
  5. Erik.Ha

    Erik.Ha Supporting Actor

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    Wait... how can 3 db be double??? Its putting out like 100 Db+...

    Explain?
     
  6. PaulT

    PaulT Supporting Actor

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    The decibel scale is logarithmic. A doubling of the power (or voltage in this case; from the receiver going into the LFE inputs) increases the output by 3db.

    Here's a link:
    http://www.phys.unsw.edu.au/~jw/dB.html
     
  7. Dan Halchak

    Dan Halchak Stunt Coordinator

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    Uhmm, to be honest with you, when you split the signal it does a whole lot of "not much." Most amps when connected to a single speaker will average the input and send it to the speaker.

    To test this for yourself, plan a 30 second sine wave and yank the plug, there is virtually no change on the SPL meter. You might notice a 3db increase, but I didn't. At least if your amp is good anyways.

    The only REAL thing splitting the signal does is give the "auto on" feature an easier time recongnizing a signal is incoming.
     
  8. Kernel X

    Kernel X Extra

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    Dan is right, the only thing that connecting to both L & R jacks is give you a better signal for your on/off function.
     
  9. John Garcia

    John Garcia Executive Producer

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    The reason the signal sensing function works better with both connected is due to the higher input voltage. That increase in voltage means the sub will have a slight gain by using both inputs, though it will not be 3dB because we are talking about input voltage not amp power, the wattage of the amp has not been increased in this case. The two inptus are summed back together and fed through the same amp inside the sub. Once calibrated, you will essentially have the same thing you started with, though you may be able to lower your sub's gain a bit, allowing for some additional headroom. IMO, use both inputs.
     

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