wired speakers to sub-no sound, why?

Discussion in 'Archived Threads 2001-2004' started by dan levatan, Nov 5, 2002.

  1. dan levatan

    dan levatan Extra

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    I just purchased a vtf-2 sub and 2 frnt def tech 350's
    2 rear def tech bpx and the c2 center chnl.
    i wired the frnts and rears directly to the sub but got no sound. I then wired them to the receiver Denon 1803 and got great sound. I have 2 questions.

    why no sound when wired to the sub?
    If they are not wired to the sub I suppose I can't use the x-ovr on the sub can I?

    Any help would be appreciated.
     
  2. Bob McElfresh

    Bob McElfresh Producer

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    Hi Dan.
    How did you wire the sub to the receiver? Did you use a cable connected to the LFE output or did you send the full-range speaker outputs to the sub?
    I suspect you just used a single cable. This cable only carries the ".1" and low frequency sounds so there would be nothing to pass onto the speakers.
    You need to send the speaker-level output to the sub, then it will strip off what it wants and pass the rest onto the the other speakers.
    (Does that sub actually take 4 sets of speaker inputs & outputs? Most subs only take 2. Dan - did you really wire 2 speakers to the sub outputs, and 2 more speakers to the sub INPUTS? [​IMG] )
     
  3. dan levatan

    dan levatan Extra

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    Bob you know your stuff.

    I did wire 2 spkrs to the inputs and 2 spkrs to the outputs.
    My mistake, hey Im new. Good excuse uh?

    Now, do I wire 4 speakers to the outputs and leave the inputs alone or do I need to run wire from inputs to the receiver as well. I already have a single monster cable running from sub to receiver.

    Thanks
     
  4. Bob McElfresh

    Bob McElfresh Producer

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    Ok, there are 2 different ways to wire a sub:
    A) You run Speaker Level L/R signals with speaker wire to the sub, then more speaker wire from the sub to your L/R speakers. You tell your receiver that your L/R speakers are LARGE, and all others are SMALL and subwoofer to NONE. This will force the receiver to send the ".1" signal, and all low-frequency signals for every channel to your L/R speakers. The internal power supply for the sub is not really used, but you do get to use the crossover adjustment on the sub.
    B) You run a single cable from the LFE port on the receiver to the LFE port on the sub. You tell your receiver that all your speakers are SMALL and that you have a subwoofer.
    Hookup B is the simpler and prefered connection. Yes, this means the receiver is doing the crossover function. Some receivers have adjustable crossover settings. Check your manual.
    PLACEMENT: (This is usually the next question)
    You get a LOT of sub sound from nearby wall reflections. So you want to place your sub in a corner with the 2 longest, un-broken walls to let it reflect the lowest, gut-wrenching frequency.
    Disconnect your speakers, fire up a bass-heavy CD or movie track in a A->B repeat loop and put the sub in place of your central listening position. Go to your target corner and crawl along the floor in both directions and listen to the boom. Some areas will sound boomy/loose, and other spots the bass will sound smooth and tight. Mark the locations that sound smooth & tight with masking tape (or a can of beer) [​IMG]
    Put the sub in the first/best position and sit back in your primary seat. Does it still sound good? Now move to your left/right (where others would be sitting). Does it still sound good? If not, try another spot. Keep doing this until you find a spot for the sub that sounds good in all the main seats. (You may have to move the sub as much as half-way along one of the walls to get this.)
    Moving the sub an inch or so can make a big difference so be patient. Having some friends over can make the process go quicker and be more fun.
    FINAL STEP: Re-connect your speakers, put a Radio Shack analog SPL meter on a camera tripod in place of your primary listening position and level-adjust your speakers AND the sub. If you use a setup DVD like AVIA or Video Essentials, adjust all the speakers to 75 db but adjust the sub to:
    Video Essential: 85 db
    Avia: 83 db
    Now you have a properly placed and calibrated HT system.
    Is this a lot of work? - No...this is a hobby. You start by throwing the sub in a corner and just enjoying. Then you do all this adjustment/calibration when you have a free afternoon on a weekend.
    And if you catch yourself listening for flaws/problems with every movie - back off. Many of these adjustments are nuance/judgment calls. It will never be perfect, it can always be better. Just give it your best shot and then enjoy the music/movie.
    Good Luck.
    PS: Congratulations on the choice of the HSU sub. You have obviously done some homework or gotten some good advice.
     
  5. Ole

    Ole Stunt Coordinator

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    Bob,
    I already have the DIGITAL Radio Shack SPL meter, will it also do the job?

    I just set my system up last night, and after setting the SPL of each speaker per Yamaha instructions and after watching Braveheart, noticed I wasn't getting much in the way of surround effects.

    Can I get a good setup using the test sound sweep coded in my Yamaha RX-V730, or should I get a setup DVD, if so where is a good source for the DVD?
     
  6. Bob McElfresh

    Bob McElfresh Producer

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    The Analog SPL meter is a bit easier to judge, but the digital unit will work just fine.

    Also, there IS a bit of volume difference between the receiver test-tones and a setup DVD, but as long as you are adjusting all the speakers with either the test-tones, or a setup DVD, you should get darn close.

    A setup DVD does have a few advantages:

    - The setup DVD has test-tones for the subwoofer. Yamaha does not include subwoofer tones (at least my older units dont).

    - A setup DVD keeps the sound running to each speaker for a long time. This gives you a chance to fumble through the menu to get to the level-adjustment. The internal test-tones go to each speaker for a few seconds, then switch. Kind of a pain when you are first learning how to do it.

    - The setup DVD talks you through how to setup the speakers, test for polarity, and use the sound meter.

    - A setup DVD also has video brightness/contrast test patterns for the video, and tutorials on how to adjust the major parameters.

    So while you can use the internal test tones, there is a lot to be said for the Avia disk. See if your local stores will rent it to you, or put it on your Christmass list. At under $45, it's a nice little gift.

     
  7. Ole

    Ole Stunt Coordinator

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    Thanks. I calibrated last nite at 70 db. I will try again at 75 to see if there is any difference. I will also see if Netflix has the test DVD.

    My other problem is that my speakers are designed for a wall mount and I had to do a ceiling mount so they are a bit hard to aim right now. When I get a chance I will make a angle bracket to mount them in the correct position.
     

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