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Cabling 2 x subwoofers. Advice please.

Discussion in 'Subwoofers' started by Messiah, Feb 6, 2004.

  1. Messiah

    Messiah
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    I have 2 subwoofers which are currently connected with the first being cabled to the amp (Denon A1SR) via a 15m cable and the second being wired from the output of the first via another6m cable.

    My question is whether I would be better splitting the output at the back of the amp with a Y cable and running 2 separate cables, 1 to each sub.

    As I have to lengthen the cable from sub 1 to sub 2 (to re-route it) I was just wondering whether there is a better way to cable them.

    Thanks.
     
  2. Zone

    Zone
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    Sorry can't answer your question Messiah but the way you are proposing to hook them up mean's you'll be getting mono bass from 2 subs yes? Isn't there a way to hook them up so you get stereo performance?
     
  3. Messiah

    Messiah
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    Sorry, don't undertstand. I will have them both connected to the LFE output of the sub. That is the correct way I understand.

    My alternative (AFAIK) is to wire each of the respective front speaker and make the necessary changes in the amp setup. Cabling would certainly be a lot easier but just not sure if that is a better or worse way.

    Thanks.
     
  4. chips

    chips
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    If you did that, you would lose all of the information contained on the DD/DTS LFE (.1) channel, which is mono.
     
  5. Messiah

    Messiah
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    OK guys. Maybe you can advise which of the following 3 options is best then.

    1. Take cable from Amp LFE output to first sub and then a second cable from sub output to second sub. (as now)

    2. Split the LFE amp output using a Y splitter and cable each sub independently from the amp.

    3. Take the existing front speaker cables and connect to the High level inputs on each sub then take the HL output from each sub to the respective front speaker.

    All above making the necessary changes in the amp setup and sub adjustment dials.

    Ideas? Many thanks. Does my head in all this audio stuff :)
     
  6. Ian J

    Ian J
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    Somehow I don't think that option 3 is a good idea.

    I don't know the answer to your question but I would guess that a feed directly from the LFE output of your amp to each sub would be the best bet as daisychaining the subs together with long signal runs and utilizing a passthrough on one sub must degrade the signal but I don't know whether the degradation would be significant enough to be audible.
     
  7. Messiah

    Messiah
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    Thanks Ian. I'll give it a go splitting the LFE output at the sub (shame the A1SR only has one LFE out :mad:)

    Thanks all for advice.
     
  8. Dutch

    Dutch
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    Messiah,

    SVS say in the manual for the 20-39PC+, that a "Y" splitter should be used to feed 2 subs from one LFE output. Hope this helps.

    Steve
     
  9. Messiah

    Messiah
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    Great, thanks Steve :)
     
  10. Stellavision

    Stellavision
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    Point 3 I wouldn't do, as you would lose your .1 channel on multichannel sound, as chips already said.
    Point 1 would work, but I've never heard of it done before, and I beleive using a Y-splitter to be the reccomended method by most sub manufacturers.
    Just guessing here, but I think that using a Y-splitter would potentially give a cleaner sound, less chance of distortion and avoid reducing headroom on the 2nd sub. With the second sub wired from the output of the first, I imagine the output volume on the first sub to also act as the output gain for the second sub. While taking two feeds directly from the amp you only have the one output gain to worry about for both subs.
     
  11. Jase

    Jase
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    Option 2. Simple & effective. ;)
     
  12. thackl

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    It all depends what needs to be achieved.

    option 1 & 2 are very much the same and as long as there is a line level output on the first sub the same signal is sent to the second. The option that achieves a shorter cable length for sub 2 would be the preferred. Sound quality would more depend on what type of cable is being used. Above all with option 1&2 you rely on the frequency x-over in your amp rather than the subs.
    option 3 will give you better control to blend each sub with the corresponding speaker, especially for music. You will not lose the .1 channel as long as you can set your amp to divert it to the main channels.

    The final choice would depend on the quality and flexibility of amp & subs x-overs.

    Cheers
    Tom
     
  13. Messiah

    Messiah
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    Thanks. Now I'm even more confused.

    Amp is a Denon A1SR
    Speakers are Celestion C series. (C1's for front)
     
  14. Ian J

    Ian J
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    Why - we have (almost) all agreed on option 2 with the sub crossover being handled by the amp.
     
  15. Stellavision

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    I can see the confusion about the .1 channel, I made a slip saying you would lose the .1 channel using your described option 3. As thackl said, you could divert the .1 channel to your mains by selecting 'LARGE' and no sub on your amp. This would divert all LFE to your mains, and of course your sub connected to them. The big draw back with this is your amp needs to cross over below your mains cut off frequency. If some of the lfe is allowed to pass through your mains as well as the sub you may risk damaging your main speakers if used at loud listening levels with no bass peak limiting.
    As an example, my Mission M74i's have a suggested frequency response down to 44Hz. I tried sending the lfe to them once and tested them with Attack of the clones first scene. The result was they flapped big time and the drivers were busting a gut. If I were to wire a sub with each of my Missions, my Pioneer will only cross over down to 50Hz, so I would expect potentially damaging lfe to be allwed to pass through my mains as well as the sub.
    Souldn't be too bad for music, but I wouldn't reccomend it for films, particuarly at fairly loud levels.

    If you are happy with the results you are getting now then why change it. However, I think we are all agreed that option 2 is the most conventional way.
     
  16. chips

    chips
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    I'm not so sure this is correct. My understanding is that if you set speakers to small the amp will divert any frequencies below the crossover point to the sub channel, these frequencies are added to the LFE (.1) information. However, I dont think that the LFE is diverted to the mains when you select large. I could be wrong on this, but I believe that's the way most amps manage bass.
     
  17. Stellavision

    Stellavision
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    I just tested out the .1 thing by using my pc's 5.1 test tones. With my sub turned off and speakers set to large I get no tone output from the mains. This probabaly is suggesting that you will only get .1 when fed from your amps sub out.
     
  18. hornydragon

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    I am with chips, setting fronts to small and crossover on the amp will send it all to the subs but set fronts top large, no sub it should send LFE to both fronts hence one sub connected to the high level ioutputs of the sub, sub will filter bass with its internal crossover (hence accurate setup needing to be done manually with an SPL more work but i think could lead to a better sound with 2 subs.

    Sorry if i have confused you messiah.
     

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