Subwoofer connection - novice question

Discussion in 'Archived Threads 2001-2004' started by SteveKNJ, Jan 27, 2003.

  1. SteveKNJ

    SteveKNJ Stunt Coordinator

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    I currently have an inexpensive RCA 2600 HTIB system. The receiver has burned out and I am looking to replace it with a better one. The subwoofer that came with my 2600 is connected using 2 wires, just like the front and surround speakers. Most of the receivers I have looked at only have an RCA composite connection, is there any way to connect this sub to a receiver like this? I would prefer not to have to buy a new sub at this point and save up for a decent one. I know the sound won't be great, but it will do for the time being if I could manage this.

    Any help would be appreciated. Thanks
     
  2. Bob McElfresh

    Bob McElfresh Producer

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    Hi Steve.

    There are 2 traditional ways to hook up a sub:

    - Run L/R speaker-level signals to the sub. Then more speaker wires from the sub to the L/R speakers. The sub will strip off the signals it wants to handle, and pass the rest to the main speakers.

    - A coaxial-cable from the LFE output of the receiver.

    Does your sub have L/R OUTPUTS? If so, you can hook it up to nearly any receiver as I have described above.
     
  3. SteveKNJ

    SteveKNJ Stunt Coordinator

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    That's correct, L/R outputs, nothing else. So how would I hook those up to a receiver that only has L/R inputs to the 5 main speakers and the only connection for the sub is via RCA? For example, I was looking at the ONkyo TX-SR500 and did not see anywhere to input L/R cables for a sub.

    Thanks
     
  4. Bob McElfresh

    Bob McElfresh Producer

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  5. Mathew Shelby

    Mathew Shelby Second Unit

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    As an alternative to the Sony, many people have also highly regarded the DLS 10" for ~$100 plus shipping from www.partsexpress.com. Unfortunately, they are on backorder till the first of the month (as I am waiting for one as well).
     
  6. Allan Jayne

    Allan Jayne Cinematographer

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    It depends on whether the sub is "powered" (plugs into an AC outlet) or not.

    A non-powered sub with a single set of terminals is connected up to either the amp/receiver left or right channel speaker outputs or a "subwoofer" speaker output if any. The amp must be rated to feed speakers with half the impedance of the sub if a regular left or right speaker is also connected to the same amp output. Don't connect both the amp left and right speaker outputs to the sub unless the sub has two sets of terminals, one for each amp output.

    A powered sub can also be connected to either the amp left or right channel speaker outputs but speaker level controls must be put in between. Provided it works with the speaker level controls no more than 1/4 the way up, you can connect both left and right speaker outputs through separate level controls to the same input on the sub. Here the amp impedance only need match the impedance of the regular speakers connected to it. The powered sub can also be connected to the amp left or right VCR output or audio output RCA jacks, if any. It is possible that due to some idiosyncrasy (not enough amplification within the sub for the input signal furnished) this method doesn't give much sound volume.

    Video hints:
    http://members.aol.com/ajaynejr/video.htm
     
  7. SteveKNJ

    SteveKNJ Stunt Coordinator

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    I meant outputs...silly me!!! I will look into the subs that were suggessted. The price isn't TOO outrageous!!
     
  8. Bob McElfresh

    Bob McElfresh Producer

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  9. SteveKNJ

    SteveKNJ Stunt Coordinator

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  10. Micheal*Johnson

    Micheal*Johnson Auditioning

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    you wrote:
    =============================================
    Run L/R speaker-level signals to the sub. Then more speaker wires from the sub to the L/R speakers. The sub will strip off the signals it wants to handle, and pass the rest to the main speakers.
    =============================================

    My new JVC receiver has 2 sets of front speaker outputs. Can I just run one set of front outputs to my front speakers and the other front outputs to my subwoofer? Is there some disadvantage to not running wires first to the sub and then from the sub to the front speakers?

    Logistically and aesthetically I’d prefer to only run wires in (and not out) of my sub, unless there’s a noticeable difference in sound quality using this method.
    (note: I have an old, unpowered Corwin Vega subwoofer. It has l/r wire inputs and l/r wire outputs, no RCA jacks).

    2 related issues:
    Subwoofer condition- my sub has apparently disintegrated a bit (due to age I guess). A 2-inch piece of the speaker has fallen off on the outer edge. Does this render the speaker useless? Is it even worth hooking this up, or can I still get something out of it?
    Speaker wire gauge- I have a JVC 100w receiver and Sony SSM-FM600 front speakers. I bought 18 gauge speaker wire- am I o.k. with this gauge?
     
  11. DaveVan

    DaveVan Extra

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    Steve:

    I have the previous model, the RCA RT2500.
    The passive sub output has the crossover built into the reciever, so hooking up the sub to a full spectrum output is not the best idea.
    If the sub you have is still the model with dual 5" drivers, you will really notice the difference with a decent (10" or bigger) powered sub.
    Also the sub (for mine anyway) was rated for 200w @ 3 Ohms impedance. Hooking up a 3Ohm load by itself may damage the amp.
     
  12. Allan Jayne

    Allan Jayne Cinematographer

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    >Receiver/amp has two sets of terminals each for front left, front center, front right speakers. Normally used for speakers in different rooms and a switch on the amp chooses which.

    >Sub has two sets of terminals, one for input, one for output. The amp output is connected to the sub and the sub connected to the regular speaker.

    In both of the above situations, unless you know for sure otherwise, the sub and the regular speaker hooked up to the same amp channel must each be twice the lowest impedance the amp is rated for, as an example a 4 ohm amp output needs both the sub and the regular speaker to be at least 8 ohms. This is because both the above situations are probably equal to two speakers connected in parallel. The exception is if the sub has a good crossover and its instructions contradict what I said and you use the second method above.

    If a speaker has a hole in its cone or a portion of the cloth or foam around the cone rim is missing so you can see what is inside the cabinet, the sound will be noticeably degraded.

    The 18 gauge wires may result in noticeable degradation if they are more than ten feet long and you turn the volume way up.
     
  13. Micheal*Johnson

    Micheal*Johnson Auditioning

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    you wrote:
    =========================================
    In both of the above situations, unless you know for sure otherwise, the sub and the regular speaker hooked up to the same amp channel must each be twice the lowest impedance the amp is rated for, as an example a 4 ohm amp output needs both the sub and the regular speaker to be at least 8 ohms. This is because both the above situations are probably equal to two speakers connected in parallel. The exception is if the sub has a good crossover and its instructions contradict what I said and you use the second method above.
    ==========================================

    Allan, thanks for this detailed info. Unfortunately, being a newbie I have virtually no idea what crossovers, ohms, amps and impedance mean. I will try to find out what these specs mean, but even then I wouldn't have any idea what the specs are on my nearly 15 year old Corwin Vega sub (owner's manual is long gone). I'm not sure I could even determine the model of this sub because I don't think there's a number displayed on the unit. So, my situation is I don't know anything about my sub, but I'd still like to try to use it.

    I'm still not clear on whether it's absolutely necessary to run wires from my sub to my fronts, or whether I can run wires from my receiver to the sub and fronts separately, using the two separate sets of front outputs on the receiver.




    Any further suggestions would be appreciated
     

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