Help with Subwoofer Wiring

Discussion in 'Speakers' started by GregBe, Jul 9, 2003.

  1. GregBe

    GregBe Second Unit

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    Please forgive me if my terminoloy is wrong. I am new to this.
    Because I have satellite speakers for my fronts and my Denon receiver has a fixed 80Hz crossover, it has been recommended that I use the speaker level inputs as opposed to the line level inputs to my subwoofer. This makes sense to me, because I don't want to lose out on the signal from 80 Hz to 120Hz.
    My big concern is loss of signal using speaker wire vs a good quality sub interconnect. The run from my receiver to my sub is very short, only 5-10'.
    Is this the right setup, and is does it matter what type of speaker wire I use?
    Also, if I do set it up this way, does it matter if I go from my receiver to my sub to my satellites; or should I wire both my satellites and my sub to the same post on the back of my receiver?
    Thanks for your help.
     
  2. Harry Lincoln

    Harry Lincoln Stunt Coordinator

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    I'd connect the sub through the sub out rca connector. set the sub crossover at the highest point and let the receiver's crossover do the work. The bass from the 5 main channels will be crossed over to the sub at 80hz and the full range lfe signal will be sent to the sub (20hz - 120hz). (you wont be able to achieve this using the speaker level inputs.)

    The only time I would use speaker wire connectors to the sub is if your receiver didn't have a sub out jack. Using the speaker level inputs wont allow your 10db headroom extension over the other channels.
     
  3. Ryan Schnacke

    Ryan Schnacke Supporting Actor

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    I understand why you're tempted to try the speaker-level connection. You're worried about gap between the crossover point (80Hz) and your satellite speaker's low end response (120Hz).

    But you've got to remember that the crossover is not a brick wall. Your sub will still have some fair amount of output up to 120Hz. And likewise your satellites will output at some level down to 80Hz. I'd try the line-level hookup first just to see if there really is a noticeable gap. This is such a more elegant solution. Just remember to set all speakers to small.

    Wiring multiple sets of speaker wire to and from the sub is just a mess. And besides, you could only use the speaker-level crossover for your 2 main speakers since the sub only has 2 speaker-level inputs. Your center channel and surrounds will still have to rely on your receiver's crossover. Plus the subwoofer's crossover is typically not as good as the receiver's. Usually a 2nd order instead of a 4th order. And the crossover frequency knob only controls the low-pass side. The hi-pass is usually fixed at around 100Hz or 120Hz.

    I'd only use speaker-level connection as a last-resort.
     
  4. GregBe

    GregBe Second Unit

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    Thanks for the advice
    O.K., Maybe I am insane, but I keep reading this article, and they make it seem so obvious to set it up through the speaker level if you have satellite speakers that only go down to 120. If I set up the sub out of the fronts, set the fronts to large, and turn off the sub setting in base management, doesn't that in effect route ALL of the LFE channel to the front. Also set the center and surrounds to small, won't the same thing happen. If I don't set it up this way, the artilcle keeps saying that I will have a hole for all sound between 80-120
    Help please I just want to set this thing up the right way.
    Thanks

    polkaudio.com/home/faqad/advice.php?article=bassmanage
     
  5. Edward J M

    Edward J M Cinematographer

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    The low pass filter rate for most subwoofers is 24 dB/octave, which pretty much IS a brick wall.

    The high pass filter rate for the surround speaks is 12 dB/octave, which of course is half as steep and will allow the surround speaks to play well below the selected filter point.

    Regardless, if Greg is using tiny sats, they are rated at -3 dB at 120 Hz and they can't possibly be expected to play at 80 Hz or even lower.

    Furthermore, if they are Polk sats, (and I suspect they are) they probably have a built in filter at 120 Hz to prevent them from playing any lower and damaging the tiny mid range driver.

    Yes, the sub cable is more elegant and easier to use, but if he is stuck with a fixed 80 Hz subwoofer crossover on small, he will experience a HUGE hole in the FR between 120 and 80 Hz and it will sound like hell.

    In this case, he is far better off setting his L/R mains to large, the rest of his speaks to small, the sub to off, and hard wiring the L/R mains output to the subwoofer and setting its filter to 120 Hz and then wiring back to the L/R sats.

    Yes, it is a mess and a PITA, and that's why most enthusiasts eventually gravitate away from tiny sats to much larger bass-capable speaks all around that can easily tolerate an 80 Hz crossover via the bass management circuit in the AVR.

    To answer your question, any decent 14 gauge speaker will will do the trick. No need to get fancy at this level.

    Regards,

    Ed
     
  6. GregBe

    GregBe Second Unit

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    Thanks Ed,

    So if I do it this way, am I correct in saying that all of the sound from the LFE channel will be routed to the fronts, so as not to miss anything.
    If so does this work with both Dolby Digital as well as DTS.
     
  7. Edward J M

    Edward J M Cinematographer

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  8. Steve_D

    Steve_D Second Unit

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    Yes you are correct and yes,it will work on all modes.
     
  9. Geoff L

    Geoff L Screenwriter

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    Hi Greg

    Ed got you taken care of, I'm sure your happy to know for sure now how it has to be set-up...

    The reason why everyone was looking for you to go the usually way was:
    ~{You did not make clear your Mains, Center, & Surrounds speakers only went down to 120Hz in extension}~.

    Had the other posters "known that critical point" in your first post instead of your 3rd, it would have made it much easier for the proper answer to your question to coe much quicker.

    It all worked out in the end so your good to go![​IMG]
    Your Denon is a very nice receiver, but the fixed 80-Hz crossover dose Bite (in just your type situation)!

    Hope you get it up and running now so you can finally ENJOY your toys!

    CURIOUS:
    =======>
    If they are brand new, could you take them back for a refund and put that toward speakers that play below 80-Hz??
    =======>
    Is it a speaker size thing with the better half or are they not new???
    =======>
    It would certainly make for a much easier set-up/install opposed to the way these have to be set up.....

    Regards
    Geoff
     
  10. MichaelJL

    MichaelJL Auditioning

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    I came across that same article from Polk which had me wondering about the connection as well. I think....well I know...I got a tad lost in your descriptions.

    I'm planning on getting a SVS 2+ sub and either a Denon 3803 or H/K 7200. Haven't quite made up my mind. I'm upgrading from an old H/K AVR 30. Front speakers are B&W 805 Matrix (small bookshelf type), and 3 rear surrounds are Paradigm Reference ceiling speakers.

    If I go with either of these receivers (3803 or 7200) is the subwoofer connection any different?...would I use the sub out or go the route that Polk recommends?
     
  11. Harry Lincoln

    Harry Lincoln Stunt Coordinator

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    Dont know about the HK but the denon has adjustable crossover points from 40hz - 120hz, so use the sub out rca connector.



    ---------
    ~{You did not make clear your Mains, Center, & Surrounds speakers only went down to 120Hz in extension}~.
    Had the other posters "known that critical point" in your first post instead of your 3rd, it would have made it much easier for the proper answer to your question to coe much quicker.
    ---------

    Spot on Geoff.
     
  12. Ryan Schnacke

    Ryan Schnacke Supporting Actor

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    "I'd try the line-level hookup first just to see if there really is a noticeable gap."

    I stand by this statement. At this point you probably already own everything that's needed to give it a shot. So it will cost you nothing except time and not much of that. If you don't like it, switch to speaker-level.

    80Hz to 120Hz is half an octave. Yeah, your sub will be 12dB down at 120Hz but your speakers will only be, what, 3dB down? Anechoically you wouldn't lose more than 10dB. That's no worse than most room modes. Who knows, you might be pleasantly surprised.

    I'm a firm believer that experimentation is always worth the effort. Especially when there is no cost.
     
  13. GregBe

    GregBe Second Unit

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    Sorry about the confusing initial posts :b
    I tried different connections, and it worked best with the speaker level hookup. At some point, I intend to upgrade to larger fronts that reach down to 80, but for now, I am pumped about my new setup.
    An example of the difference is in the T-Rex Scene from JP. I was getting most of the deep base, but the part where the goat part goes thud on the windshield sounded like a tennis ball hitting the windshield. When I went through the speaker level it had its proper thud and startle effect.
    One last question, and I will stop bugging everyone. The back of my Denon has Front Left and Right preamp outputs. Is there any advantages and/or disadvantages of using these to my sub, and setting up the front sats normally through the speaker outs.
    Thanks for everyones help [​IMG]
     
  14. Derek N

    Derek N Agent

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    I have had this question myself and the answers are great. Now I have an additional one (as long as its not considered hijacking the orginal question).

    I have Polk satelites as well (RM6700) and read the same article. I had my system hooked up with the speaker line inputs. I just upgraded through CC my PSW202 for a Velodyne CHT-10 (i realize there are other options in this price range but this way I did not have eat the cost of the psw202 as the full refund is put towards the upgrade).

    Now that I am doing the hook up all over I was looking into this issue again and along came this thread letting me know I was not the only one wondering about this.

    The sub out is certainly the cleanest hook-up and because I have a HK AVR-325 I have variable crossovers for all speakers built into the receiver. This should take care of the above issue.

    Now the question (finally) - What about Stereo output? As in Stereo direct or non-digitized output. Will it still output to the sub or will it now only be the L and R which are set to small and not ideal for this application. I have read the manual and it is not clear on wether the sub gets a signal in plain stereo mode.

    Derek
     

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