Please Help with Connection for Subwoofer

Discussion in 'Archived Threads 2001-2004' started by Mike_Camden, Apr 7, 2002.

  1. Mike_Camden

    Mike_Camden Auditioning

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    Hi. This is only my second post on this forum; I'm a home theater newbie, so please forgive my lack of knowledge in the below questions.
    My issue is that I need to to know if I can (and if so, how) hook up an RCA 100 watt powered subwoofer that only has speaker wire inputs to a JVC RX-6020VBK DD/DTS receiver with only an RCA output for the subwoofer. The only answer I've received is that I can plug my subwoofer speaker wires into the receiver's speaker wire outputs for the L/R front speakers. If I do this, will I lose bass and/or sound quality? Isn't there anyway to convert the speaker wire from the subwoofer to an RCA input without damaging my equipment?
    If anyone is interested in how I ran into a problem like this, I've posted my negative experience with an RCA Home Theater in a Box here.
    Thanks for any help,
    Mike C.
     
  2. Bob McElfresh

    Bob McElfresh Producer

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    Hi Mike.

    A "traditional" subwoofer/Sat system sends the full-range L/R audio to the sub. The sub then takes what sounds it wants, and passes the rest to some outputs. You run more speaker wires from these to your L/R speakers.

    No, you dont loose anything by wireing this way.

    Let me explain the 2 levels audio signals in your system:

    - RCA Plug: This puts out/takes in what are called "line-level" or un-amplified signals. They cannot drive a speaker or produce sound without going through an amplifier.

    - Speaker Connectors (5-way binding posts or clips): These put out/take in AMPLIFIED signals carrying POWER. The energy is enough to drive a motor.

    You never want to mix these two.

    Something about your post confuses me:

     
  3. Jimmy P

    Jimmy P Stunt Coordinator

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    The answer you received was correct,run speaker wire from the receiver (main L/R) to the sub,then run speaker wire from the receiver (main L/R) to the sub,set the receiver so the mains are large,center small,rear small,no sub,the only sound that you will miss will be the inability of the RCA speaker package.Try it out,see what you think and go from there.I did edit the above after reading the RCA manual,I think you would be better off if you could at least buy a different sub,then you could realize the benefit of your upgraded receiver.
     
  4. Vin

    Vin Supporting Actor

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    Mike, run speaker wire from your receiver's main channel outputs to the sub's speaker level inputs. Then run speaker wire from the sub's speaker level outputs to your main (left and right) speakers.

    In your receiver's set up menu, set the mains to LARGE and sub to OFF and all other speakers to SMALL.

    With this configuration, all low bass (below your receiver's crossover) for speakers set to SMALL (in addition to the LFE channel) will be routed to your mains (which should be set to LARGE as noted above). You would then use the sub's low-pass crossover to adjust the upper limit of the sub's frequency response. For movies you'll probably want to set this higher than you would for music listening because the LFE channel on DVDs can contain info as high as 120 Hz.

    The sub's high-pass speaker outputs (probably fixed somewhere between 80 and 100Hz) will send anything above this point to your mains.

    Hope this helps,

    Vin
     
  5. Mike_Camden

    Mike_Camden Auditioning

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    Gents,
    Thanks for the responses and the detailed explanations. I appreciate the help.
    Bob, I'm pretty sure that the subwoofer only has a single pair of speaker wire inputs and no RCA jack. I'm away from home for the next three weeks though, so I'll have to double check it when I get back. The subwoofer doesn't have a power cord. I did a little more checking, and it seems that while RCA advertises the package as having a 100-Watt Powered Subwoofer, the amplifier is actually built into the receiver that came with the package (which is the part I've replaced). I take it that this probably means that the subwoofer is passive and must be hooked up via speaker wire vice an RCA connector to receive power as well as the audio signal. The RCA product page is here. It's not very helpful though because it gives very limited info on the subwoofer.
    Thanks again everyone,
    Mike C.
     
  6. Bob McElfresh

    Bob McElfresh Producer

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    I went to the web site and looked at the manual. You are right. The receiver from the kit has a dedicated 100 watt amp to drive the PASSIVE subwoofer.

    Looks like you should buy the Sony SMA 40 as an alternative, or if you have a spare receiver you can use it to drive that sub.
     

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