Subwoofer behind the listening position?

Discussion in 'Speakers & Subwoofers' started by David Payne, Mar 26, 2006.

  1. David Payne

    David Payne Stunt Coordinator

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    Hi. I'm in the middle of reorganising the layout of my furnitre, and as part of the changes, I'm thinking of putting my DVD player AV unit and subwoofer behind me, as this would make more sense space wise. I know placement of the subwoofer shouldn't matter too much, but I was just wondering if anyone whos done this has noticed any difference? I tend to think of bass as being something strong that comes from the front of the room. I don't know if this is my mind playing tricks with me, or if it's just because my front and centre speakers produce a lot of bass on their own (or even if it's because I can roughly make out the direction of the subwoofer). I know my system does use the sub sparingly, as it should, and as with any half-decent system, I generally don't know how much of the bass is coming from the sub or the other speakers. But still, I'm a little bothered by the idea that my viewing experience could be changed from what I'm used to.

    And I will miss the little breeze I can feel coming from the sub sometimes! [​IMG]
     
  2. SethH

    SethH Cinematographer

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    If your sub is crossed over at 100Hz or below you shouldn't be able to localize the sounds it produces.

    However, placement of the sub still matters. Not necessarily for the direction of the sound, but rather with the way the sub interacts with the room. By moving the sub, you could excite different room modes or find new nulls that were not as problematic in your other location. Certainly give it a try and make sure you calibrate the sub.
     
  3. gene c

    gene c Producer

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    Up front somewhere between the left and right speakers is supposed to be the preferred spot but I put mine under the left end table next to my couch so I could keep the volume low (close neighbors). But being so close, it was obvious where the bass was coming from so I bought another one to put under the right side end table. Now all is well. A little less so if you are not sitting in the "sweet spot" though. Not the ideal location(s) but some of us have to compromise. I can "feel" the bass better too. In my everyday viewing room I have a single sub behind me and to the right. Localization didn't seem to be much of a problem in that room so I'm using just one sub there. That room is also smaller and I sit a little to the left.
     
  4. John Garcia

    John Garcia Executive Producer

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    I agree with SethH - choosing a spot based on where you think it should go may not yeild the best results. You'll have to try the sub out in a few spots (hopefully you have a few to try) to and see which gives you the best sound. Ideally you would take measurements and see which spot gives you the flattest response. Gene's right too, sometimes you don't have much choice. In my room, I pretty much have one spot, and fortunately, that spot works well for my sub (passive 15" Tempest). A lower crossover can help reduce localization as well.
     
  5. David Payne

    David Payne Stunt Coordinator

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    ^Yeah that's pretty much the same for me as well. I don't have (or want) a very long coax, so the subwoofer has to go somewhere near the AV unit! I didn't spend much time picking a spot last time, I just put it in the most convenient possible spot in terms of the room layout (which was still a very awkward place), and taht's always been fine. The only thing I'm worried about is that I could end up in a worse situation than I'm used to, since moving it from front to back seems to be a very big shift.
     
  6. douglas-b

    douglas-b Stunt Coordinator

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    The closer you can have it to the listening position the better....preferably the closest corner.
     
  7. Cees Alons

    Cees Alons Moderator
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    David,

    My sub is located behind the listening position: it sounds awesome. People tend to ask where the sub is, if any (the sound is located by the higher frequencies, so even the deepest bass seems to come from the fronts - or wherever the sound is supposed to come from) and when I point it out, finally, most of my friends are flabbergasted, especially the technical not-so-challenged ones (the others simply accept it).

    Now in my case, the spot I chose was also one of the best ones in relation to the room modes, reflections, etc.

    The best way to find this place (such places) is to place your sub at your listening position (in the "owners chair") and walk around the room, listening where it sounds best (don't forget to get close to the walls and listen at lower positions as well, i.e. at the height of the sub). Make sure you don't smother the speaker hole (or a vent outlet), especially if you happen to own a down-firing sub.
    Now, the place(s) where it sounded best (loudest, generally) is the (or a) place to put your sub. Hopefully, the place you had in mind appears to be such a spot.

    No complicated measurements necessary, this is the most refined technique available.

    Good luck.


    Cees
     
  8. Brian Sheldon

    Brian Sheldon Auditioning

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    agreed with several of the above, experimentation is the only and best solution. try it you might like it behind the seating position. goog luck
     
  9. ChrisWiggles

    ChrisWiggles Producer

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    Sub placement behind you should not be a problem, assuming that the sub is a quality sub and doesn't have resonances that are audible in higher frequencies that would help you localize the sub, port chuffing etc, and that it is crossed over low enough.

    Several of the recommendations for sub placement above seem misinformed.
     
  10. David Payne

    David Payne Stunt Coordinator

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    Okay, I'd just like to thanks everyone who posted above. Most of it was useful advice. Sorry I abondoned my own thread and didn't reply back, but I've just been really busy lately (but I have been reading your posts).

    Anyway, to cut a long story short, I went ahead and put the sub behind me. Actually ended up putting it at quite a high place behind the listening postion, and the effect is great. I only wanted to rearrange my room to free up space (now have my DVD player, AV unit and sub behind me), but I think I've managed to find a better suited spot for the sub! I think it may be because it's now looking straight down the room, instead of being at an angle at the site. I'm actually further from the sub now than I was before, but found myself turning the sub level down because it was too much! (never thought I'd find myself doing that!). And my fears of localising it were unfounded. It still feels like the bass is coming out of the movie. I guess your mind plays tricks with you, and bass really is difficult to localise.
     
  11. Cees Alons

    Cees Alons Moderator
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    David,

    Given the size of a normal room, and the wavelength of bass tones under 100Hz, all your sub can do is increase-and-lower the pressure in your room. It's like a pump. There's hardly any direction to those waves. In fact, there's hardly a wave.

    The perceived direction is determined by higher frequencies (including the start/stop percussion effects of the notes), hence by the other speakers.

    Glad you found a great place for your sub!


    Cees
     
  12. Jerome Grate

    Jerome Grate Cinematographer

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    I got two, 8 inch sub in the front and 12 inch sub in the back and I love it. No issues on where the bass is coming from, it fills the room. The nicest thing about the sub in the back is that it actually shakes the couch a little when the bass is intense.
     
  13. David Payne

    David Payne Stunt Coordinator

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    Yeah, I've been having some fun switching the sub off and on while playing music, just to see exactly what the effect is. It's weird how I can "hear" the bass coming from the front even though I know it can't be because the sub is behind me (it was this effect that had me worried initially, since I wondered if my ears were actually localising some bass!). I've also noticed I can localise the front speakers better with the sub off. I'm guessing this is because it's easier for your ears to find a sound with no non-directional sounds in the way. That's why it's pretty weird to hear the difference when the subs off! But, I suppose most of you already know that. I'm just finding it interesting because I've never messed around like that before. [​IMG]
     

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