wiring speaker volume controls

Discussion in 'Home Theater Projects' started by RonSAR, Oct 5, 2004.

  1. RonSAR

    RonSAR Extra

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    I want to wire two sets of 8 ohm outdoor speakers and need help with an impedance question. I intend to wire to a A, B, and A+B selector switch. Then wire an impedance matching volume control to the A set of speakers and an impedance matching volume control to the B set of speakers.

    At times the A set will be on or the B set will be on, and, at times, both A and B sets of speakers will be on.

    What impedance setting should I use?
     
  2. Bob McElfresh

    Bob McElfresh Producer

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    Are you asking about the "impedence setting" on the back of your amp/reciever?

    In theory - it should not matter. Your reciever that does the A,B,A+B will assume you DONT have a volume control and will prevent the A+B setting from running in parallel (and looking like a 4 ohm speaker). Your volume control will likely also look like a 8 ohm load so I think you will be safe.

    Or did I miss something about your setup?
     
  3. RonSAR

    RonSAR Extra

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    Bob:

    Thanks for your response. I guess I did not make myself clear.

    I want to control two sets of 8 ohm outdoor speakers and intend to run one line from the B side of my receiver to a separate A or B and A+B selector switch (one device that allows either or both sets of speakers to be on line). That selector switch will determine whether the speakers on my deck are on or the speakers on my patio (two different locations) are on, or whether both sets are on.

    I want to install impedance matching volume controls between the selector switch and each set of speakers and want to know what impedance setting (on the volume controls) should be used. I assume the receiver will read different impedance values depending on whether one set of speakers or both sets of speakers are on at the same time. How do I correct for that?

    (I would draw a diagram if I knew how).

    Thanks for your patience.
     
  4. Bob McElfresh

    Bob McElfresh Producer

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    First - the speaker selector switch usually takes care of this problem by making sure the receiver does not ever see all the speakers in parallel (which would look like a 2 ohm load).

    If your volume control has the option, set it for 8 ohms. This is the safest setting to use. Think of it this way: the closer you get to 4/3/2/1 ohms - the closer you are to a short-circuit.
     
  5. RonSAR

    RonSAR Extra

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    Thanks for your fast response. I also appreciate the comment regarding the drop in ohms getting closer to a short circuit. I had not thought of it that way.

    If I set each volume control at 8 ohms what is the net result when one set (each set being left and right 8 ohm speakers) is on line and when two sets of speakers are on line. What ohm value(s)does the receiver/amp read?

    Thanks again for your patience.
     
  6. Dean_S

    Dean_S Second Unit

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    You don't need the a+b switch if you use impedance matching volume controls. I use the Niles controls and the lowest volume control setting is off (or at least you can't hear any sound).
     

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