Does it matter where the subwoofer is placed in relation to the two speakers it supports?

Question

I am in the process of re-arranging my house, and part of that process is upgrading my speakers. I am leaning towards wall-mounted speakers, in the interest of space. With those speakers comes a sub-woofer, and the way the room is laid out, it would be next to impossible to center the sub-woofer directly between the speakers. It would almost certainly be placed closer to one or the other speakers.

I can't imagine this would cause a very noticeable difference in the sound output, but I'd like to verify this before I progress. The speakers haven't been purchased yet, and if they will sound off-balance, etc, then I will explore other options. I have a subwoofer for my PC speakers, but it just so happens that I am able to place it in the center of the two.

This is a very naive question, but I appreciate any feedback. I've never heard or read that subwoofer placement makes a difference, but I'd like to know for sure.

Answer 1

Even though bass is omnidirectional, the problem with one subwoofer is that you are going to experience what is called null voids, or empty bass spaces.  So placement is key to minimize those null voids.

Now if your main speakers can handle a decent lower Hz frequency, this will help to some degree, but main speakers will never get that deep impact that a dedicated sub will get.  I used to have a pair of mains that handle bass pretty well and a subwoofer all along the front wall, sub was just on the outside of the right main speaker.  But I was getting null voids in bass in the main sitting position, because of sub placement and this is not what you want.  So I moved the sub in the back of the room and although bass was great in the sitting position, I was now getting less bass in the front of the room (where all the action on screen was taking place.

Solution was to buy a pair of mains that had built in subwoofers (Def Tech BP7001sc, each with 10" subs and 1,500 watt amps)  This cured all null voids and I now after calibration had overall bass coverage.

Granted most don't have the budget to accomplish multiple subs, but I always suggest that at minimum you have two subs to help conquer all null voids.  Just place on opposite sides of a room, but if one is all you can manage, then placement is going to be key (along with a fantastic subs like SVS, Hsu, Epik or Elemental Designs subs).

I suggest you have a Friend who is willing to help you move the sub around the room and have them adjust the phase and gain levels while you listen in the main sitting position to make sure you get the bass sound with minimal null voids.  And if at all possible think about buying another sub to give you that overall deep bass impact.

Also corner placement is not always the best solution, as it will increase the "boominess" of the lower end of the frequency spectrum, but will also drown out the mid bass frequency response.  You want to find a placement that is giving you the full bass effect all along the lower audio spectrum, so that you hear more than just the real deep bass.  You will also hear a 3 db increase in a corner placement which may enhance the audio distortion.  Again room dimensions and acoustic treatment and decorations will cause each room to be different.  So corner placement may work in some rooms and be a detriment in others, so please place sub with caution.

Sub placement and calibration is the hardest of all the speakers to get "tuned in" but once you have proper placement and have it calibrated to achieve 15Hz (if sub can get that low) to 80Hz while blendng in with the speakers, you will get an experience that is jst mind blowing and realistic.

Answer 2

Yeah you'll be fine. You may find that a corner location gives you more bass. The best thing to do is move the sub to several different locations and see which sounds best. In my room, it would have been the center of the room but that not practical so I chose a corner which gave me the second best sound. The sound is fairly omni-directional so centering it isn't necessary. Some people even prefer it behind the listener (but I'm not suggesting that).

Answer 3

Bass is NOT omni-directional. This is a myth.

What really happens is you get a lot of the subwoofer sounds from wall reflections.  This is what fools people into thinking you cannot tell where it is coming from.

For this reason - you dont care where the sub is in relation to the speakers.  You care where the sub is in relation to the long walls of the room.

There is a concept called "Corner Loading" for the sub.  Find the corner of the longest un-broken walls. Measure in 2/5 to 1/3 along the wall and put the sub here.  This is usually the best place to avoid over-emphasized reflections, but still take advantage of the room acoustics.

Search the internet for "Corner Loading", "House Curve" and "Subwoofer positioning" for more discussion of this topic.

Hope this helps.

Answer 4

the sound-wave from bass is non-directional.  Therefore, sub oofer placement is of little importence. You should just make sure that the ventilation port doesn't fire directly into an obstruction.  

My personal preference is to have the subwoofer placed away from a corner (reflection off of corners tend to lead to distortion), port firing forward, woofer firing down into the floor.  But, to each their own.

Answer 5

Subwoofer output is fairly omnidirectional. That is it can be placed anywhere any you can't tell where the sound is coming from.

What will impact the sound of the sub is what's called room modes and room reflections. If you place a sub in a corner (corner loading) you will get more bass output because of the reflections off the 4 surfaces (floor, walls, ceiling). It can make the bass boomy and muddy sounding.

A cool trick is to place your subfoofer in your seating position and then walk around the room to see where is sounds the best. When you find that spot put the sub there.

That might be less than idea for your room setup however so really anywhere on the front wall will work.

Answer 6

Bass is pretty non directional which gives you the ability to 'hide' a sub.  The closer it is to a wall, the better but it does not need to be near the other speakers for you to notice a difference.  An example of non-directionality is the 'boom' you hear from a car stereo.  Initially, it is hard to determine which car has the bass.