Placing mains on top of sub?

Discussion in 'Speakers & Subwoofers' started by DonnyD, Jun 16, 2004.

  1. DonnyD

    DonnyD Screenwriter

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    A few years ago, I actually had one of my mains on top of a box type sub and never noticed any problem. Changing to a cylinder SVS, I eliminated that option but now I'm about to pull the trigger on a PB2+ but my available space to locate it is limited unless I can use it as the "base" for my bookself right main.

    Anyone doing this and would you think it may affect the operation of the main or "shake" it off or something? An alternative placement will take it out of a corner load position......
     
  2. DonnyD

    DonnyD Screenwriter

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    A few years ago, I actually had one of my mains on top of a box type sub and never noticed any problem. Changing to a cylinder SVS, I eliminated that option but now I'm about to pull the trigger on a PB2+ but my available space to locate it is limited unless I can use it as the "base" for my bookself right main.

    Anyone doing this and would you think it may affect the operation of the main or "shake" it off or something? An alternative placement will take it out of a corner load position......
     
  3. BrianWoerndle

    BrianWoerndle Supporting Actor

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    The vibrations from the sub will vibrate the cabinet of the bookshelf and will cause sound to resonate inside the bookshelf. It could create undesireable sounds.

    But you really will just have to to and see for yourself.
     
  4. BrianWoerndle

    BrianWoerndle Supporting Actor

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    The vibrations from the sub will vibrate the cabinet of the bookshelf and will cause sound to resonate inside the bookshelf. It could create undesireable sounds.

    But you really will just have to to and see for yourself.
     
  5. SkiingNinja

    SkiingNinja Second Unit

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    Another issue to consider is that position may not yield the best frequency response. Typically along the long wall is best but that all depends on the room. Can you post a photo of the room so we know what you have to work with?

    Sean
     
  6. SkiingNinja

    SkiingNinja Second Unit

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    Another issue to consider is that position may not yield the best frequency response. Typically along the long wall is best but that all depends on the room. Can you post a photo of the room so we know what you have to work with?

    Sean
     
  7. DonnyD

    DonnyD Screenwriter

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    Update....

    I sent an email off to Tom at SVS and he reported back that as long as I placed something between the sub and the bookshelf to eliminate possible rattles, there should be problem with it. My primary concern was teh lamp that would be sitting on the bookshelf that we use for backlighting to accent the area and the HDTV.... it was my Mom's and is about 55 years old... don't want it falling!

    I'm gonna pull the trigger on the PB2+ and try the mounting. Under the right bookshelf is actually only 1 ft out of the corner.... if that doesn't work, I just have to relocate the entire entertainment system to the left about a ft to give enought room for the sub....

    Thanks guys..... I'll post results... in layman's terms when it's all set up.
     
  8. DonnyD

    DonnyD Screenwriter

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    Update....

    I sent an email off to Tom at SVS and he reported back that as long as I placed something between the sub and the bookshelf to eliminate possible rattles, there should be problem with it. My primary concern was teh lamp that would be sitting on the bookshelf that we use for backlighting to accent the area and the HDTV.... it was my Mom's and is about 55 years old... don't want it falling!

    I'm gonna pull the trigger on the PB2+ and try the mounting. Under the right bookshelf is actually only 1 ft out of the corner.... if that doesn't work, I just have to relocate the entire entertainment system to the left about a ft to give enought room for the sub....

    Thanks guys..... I'll post results... in layman's terms when it's all set up.
     
  9. Ted Lee

    Ted Lee Lead Actor

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    wouldn't all the bass waves (from the sub) interfere with the sound waves from the bookshelf? especially since they're in such close proximity?

    just curious....

    "bass waves" -- that may be the most untechnical term i've ever used.... [​IMG]
     
  10. Ted Lee

    Ted Lee Lead Actor

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    wouldn't all the bass waves (from the sub) interfere with the sound waves from the bookshelf? especially since they're in such close proximity?

    just curious....

    "bass waves" -- that may be the most untechnical term i've ever used.... [​IMG]
     
  11. Aaron Gilbert

    Aaron Gilbert Second Unit

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    Ted,

    There will be intereference between the bass waves (unusual term, but not technically improper) regardless of where the subwoofer is located, unless your room is just enormous. This is due to the frequencies involved. For instance, the length of an 80Hz bass wave is about 14', while 20Hz is about 56'. The way to avoid this is to set all the speakers to small so that there isn't duplication of bass waves between the subwoofer and satellite speakers.

    That said, my system actually sounds better with all the speakers set to large and duplication of the front L/R bass in the subwoofer. So even though there is quite obviously interference between my speakers, the net result is an improvement. Each room is different and plays a HUGE part in the overall result.

    But on to the original question - I don't see a problem placing a main on top of a subwoofer, as long as there's something in between to physically isolate the two. My first thought would be some thick stick on or screw on rubber feet, or for something a bit less permanent and perhaps more stable, a solid sheet of rubber or neoprene.


    Aaron Gilbert
     
  12. Aaron Gilbert

    Aaron Gilbert Second Unit

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    Ted,

    There will be intereference between the bass waves (unusual term, but not technically improper) regardless of where the subwoofer is located, unless your room is just enormous. This is due to the frequencies involved. For instance, the length of an 80Hz bass wave is about 14', while 20Hz is about 56'. The way to avoid this is to set all the speakers to small so that there isn't duplication of bass waves between the subwoofer and satellite speakers.

    That said, my system actually sounds better with all the speakers set to large and duplication of the front L/R bass in the subwoofer. So even though there is quite obviously interference between my speakers, the net result is an improvement. Each room is different and plays a HUGE part in the overall result.

    But on to the original question - I don't see a problem placing a main on top of a subwoofer, as long as there's something in between to physically isolate the two. My first thought would be some thick stick on or screw on rubber feet, or for something a bit less permanent and perhaps more stable, a solid sheet of rubber or neoprene.


    Aaron Gilbert
     
  13. Ted Lee

    Ted Lee Lead Actor

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    so aaron -

    i guess what i was thinking was that with two speakers in such close proximity that the waves would "collide" closer to eachother (since the drivers are physically closer) and that would color the sound coming out of the main speaker?

    with a sub farther away, the main speaker has had it's "chance" to reproduce the sound without this big-arse bass wave in it's face???

    yes, i'm sticking with my non-technical terms here... [​IMG]
     
  14. Aaron Gilbert

    Aaron Gilbert Second Unit

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    Ted,

    In order to introduce distortion into the main speaker output from the subwoofer, the subwoofer would need to be producing sound pressure in the 'above the threshhold of pain' category. In other words, you'd want to use hearing protection. [​IMG] I've heard of some ridiculously crazy home systems, but I don't know that I have heard of anyone actually playing at sustained levels about 125-130dB in their house, unlike what's common in cars.


    Aaron Gilbert
     
  15. Ted Lee

    Ted Lee Lead Actor

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    130db in the house? isn't a jet engine around 140db? [​IMG]

    no thx!
     
  16. Chu Gai

    Chu Gai Lead Actor

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    What's the other speaker going to sit on?
     
  17. DonnyD

    DonnyD Screenwriter

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    I'll be building a stand that matches the SVS PB cabinetry in size and finish.
    BTW: Being a former cabinet builder, I've always built my own entertainment centers, stands, etc. Recently I've been using 12" concrete forms (hollow tubes) with routed form-fitted feet and marble tops for speaker stands. Concrete forms come in various diameters and, according to how you finish them, they're pretty neat and very contemporary....
     
  18. DonnyD

    DonnyD Screenwriter

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    I'll be building a stand that matches the SVS PB cabinetry in size and finish.
    BTW: Being a former cabinet builder, I've always built my own entertainment centers, stands, etc. Recently I've been using 12" concrete forms (hollow tubes) with routed form-fitted feet and marble tops for speaker stands. Concrete forms come in various diameters and, according to how you finish them, they're pretty neat and very contemporary....
     
  19. ScottCHI

    ScottCHI Screenwriter

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    huh?

    [​IMG]

    i learn something new here everyday!
     
  20. ScottCHI

    ScottCHI Screenwriter

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    huh?

    [​IMG]

    i learn something new here everyday!
     

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