Home Audio Speaker Placement
Common Sense and Livability
No matter what we say here regarding room treatment and speaker positioning, keep in mind that a home theater system is supposed to enhance your life, not take it over. If any of our advice conflicts with common sense, or your sense of aesthetics (or would interfere with the normal function of the room) just ignore us. What difference does it make if your system sounds 5% better when you're always bumping into an ill-placed speaker? Do what makes sense.
General Home Theater
If possible, place the five mid/high (non-subwoofer) speakers on the circumference of an imaginary circle whose center point is the main (your) listening position (figure on right). At very least, left, right and center speakers should be the same distance from your main listening position. Find the placement that makes the main speakers sound best, then relocate the other components (seating position, center speaker/TV, and surround speakers) to fit the equal distance rule.
If you can make this work, fine. But if practical or aesthetic considerations get in the way, don't worry, the "time delay" or "speaker distance" function of your surround processor or receiver will compensate.
Stereo (Front L and R) Speakers
Since the left and right front channels are responsible for bringing music as well as movies to life, the stereo pair requires the most careful setup. For best performance, the speakers should be placed at least two feet from room boundaries, such as large pieces of furniture, walls and especially corners (see figure on right). Placing a speaker closer to room boundaries increases bass, but may result in a "boomy" or bass-heavy sound and degradation of stereo imaging. Try varying the speakers' distance from the rear walls, side walls, and corners until the best balance between low frequency extension and clarity is achieved. If your system has a subwoofer, chose a main speaker placement that provides the best imaging and most natural midrange balance, usually far from room boundaries. If you cannot get the speakers at least two feet from the room boundary, treat the adjacent room boundaries with absorbing or diffusing material (refer to Optimizing the Sound of Your Room.)
Place the main speakers at least a few inches in front of the front of your TV. Unless a large projection screen monopolizes your wall, don't place the speakers too close to the sides of your television, as such placement constricts the width of the stereo soundstage.
Compact speakers are designed to provide good sound when placed on a wall and often come with wall mounting brackets. But, as with other types of speakers, you should avoid placing the satellites within two feet of side walls. Since wall mounting satellites precludes placing them in front of the TV screen, place wall mounted satellites higher than the top of the TV.
Further Placement Tweaking
To minimize the effects of standing waves, we recommend as a guideline the Rule of Odds. Measure the width of the front wall (the wall the front speakers are on) and the length of your room and divide any odd number (3,5,7,9 etc.).
For example, let's say your room is 144 inches wide by 192 inches long. Divide the room width by three and get 48". Now divide the room length by 3 and get 64". These calculations suggest placing the speakers 64 inches or 5'4", from the front wall, 48" from the side walls and 48" apart. For most people 5'4" is too far into the room and 48" is too close together to support a wide stereo image. Keep dividing your room dimensions by ever larger odd numbers until you come up with a placement that makes sense for you.
To continue our example, divide the length by 5 and you get 38.4", a more workable distance. Divide the width by 5 and get 28.8". So in this example a practical speaker placement that will yield good a result is 28.8" from each side wall and 38.4" from the front wall (see the figure above).
Always use the center of the woofer as your reference point. If you calculate that your speaker should be 3 feet from the side wall, measure 3 feet from the wall to the center of the woofer cone.
Avoid symmetrical placement. A speakers' distance from the front wall should not be within 33% of he distance from the side walls. For example if the speakers are 24" from the side walls, place them at least 32" from the front wall. In our example, we did not divide room length by 7 as that would have placed the speakers 27.5" from the front wall, too close to the 28.8" side-wall distance.
With floorstanding speakers, assume that the designers have mounted all drivers at the proper distance above the ground. Bookshelf and satellite systems, on the other hand, must be elevated to bring the tweeter to seated ear level, meaning the tweeters should occupy the same height as the listeners' ears when those listeners are sitting. This can be accomplished either by placing the speakers on dedicated stands, or mounting them on a shelf or wall bracket. If the shelf is well above seated ear level, use a door stop wedge under the back edge of the speaker cabinet to point the speaker slightly downward (be careful not to make the angle so severe as to make the speaker unstable). On-wall speakers often have brackets (supplied or optional) that allow aiming of the speakers.
Once the speakers have been properly positioned, they should be adjusted to provide the sharpest possible image. This is accomplished by a process known as toe-in. Your goal is to obtain the sharpest possible image by aiming the speakers at the listener, as if you were focusing binoculars on a distant object. Start with the speakers pointing straight ahead, while listening to a CD of a solo vocalist. Rotate each speaker a couple of degrees inward, toward the listening position, until the voice seems to come from a point directly between the speakers, rather than from the speakers themselves. But beware: too much toe-in will compromise the natural width of the soundstage. Try to find the best balance between image focus and soundstage width.
Your listening position will also influence the sound of your system. The best spot is at two-thirds of the length of the room. If that isn't practical, continue to divide by odd numbers as you did to determine speaker placement. In many rooms, the main listening position is on a couch up against the back wall. This position will yield very loud, and possibly boomy bass. In this case, be sure to place your main speakers and subwoofer as far away from wall surfaces as is practical.
Since the main purpose of a center channel loudspeaker is to fix all sounds associated with on-screen action to the screen, this speaker needs to be as close as possible to your television, either directly above or below it. Just like the stereo pair, the center channel sounds best when its tweeter is mounted at seated ear level; unfortunately, this position is normally occupied by the television itself. No problem: you can achieve proper treble balance by tilting the speaker up (if it's below the screen) or down (if it's above) to aim the tweeter directly at the audience. Using rubber feet of different thickness, raise or lower the front of the speaker until you hear the most extended and detailed high frequencies. Polk even produces some center channel speakers that have an adjustable "foot" on the back of the cabinet. (I just can't avoid a "plug" when it's that good an idea!)
Unlike the front three speakers, that must produce sharply focused images, the job of surround channels is to envelop the audience in diffused sound known as ambience. To excel at this job, rear speakers should not (with the exception of localized 5.1 channel effects) call attention to themselves as sources of sound.
For these reasons, surround speakers work best when elevated at least two feet above the seated listeners' heads (a height of six to seven feet above the ground is considered normal), and mounted on the side walls in line with or slightly behind the audience (figure on right). If you are using front firing speakers, they should face each other so that the sound is projected over the listeners' heads.
If your seating area adjoins the rear wall, or if you cannot place speakers on the side wall, you'll have to position the speakers on the rear wall. In this case, bi-directional (bi- or di-pole) speakers are recommended, since they will produce the most diffuse effect. If you use front-firing speakers, do not aim them at the audience as one would a front speaker, but point them straight forward so the sound projects past the audience (figure on right). Another option is to mount in-wall speakers in the ceiling, aiming them downward at the listening area.
Low frequencies (below about 80 Hz) are non-directional, which means that, in theory, a subwoofer should sound the same whether it is located at the front, rear or sides of the audience. In reality, however, bass quantity and quality are influenced by subwoofer placement. As with the stereo pair, moving the speaker closer to room boundaries increases bass, while moving it into the room reduces output. For the greatest amount of bass output, place the sub in or near a corner of the room.
If you have a standing wave problem and the bass is very uneven throughout the room (especially at your listening position), try this old trick. Place the subwoofer at your main listening position (move the chair). Play a movie or CD with deep, sustained bass. Walk around the front half of the room until you find the spot with the best bass. Place the subwoofer there. Now you can have your chair back.
To some extent, you can compensate for room acoustics by adjusting the subwoofer's level control, but it's still advisable to experiment with various placements. Play CDs and movie soundtracks with extensive bass content, and fine tune the volume until you achieve a seamless blend with the main channels. If your sub is equipped with an adjustable crossover and your stereo speakers have sufficient low bass capability, try lowering the frequency to the 70-80 Hz region. Use the lowest frequency setting that combines powerful bass with the best stereo image and a smooth transition to the main speakers. Finally, use the phase control to maximize bass output: if your subwoofer is placed along the same wall as your front channels, set the phase to 0 degrees, if it is behind the listening position, try 180 degrees. It helps to hear phase differences if you sit in your listening position while a friend switches back and forth. As always, experiment until you find the setting that delivers the clearest and deepest response.
For more information on subwoofer placement, please read this article.
Polk speaker owners are welcome to call Polk Customer Service/Tech Support at (800) 377-7655 Option 1 for more customized placement help.
This article was last modified Dec 6, 2013