Layout Advice
When you are laying out a home theater, remember that the goal of all speaker placement for movie soundtrack playback and multichannel music reproduction-even stereo - is a smooth, consistent and unbroken soundstage across the front, coupled with a sense of envelopment in the ambient surround effects. In other words, you're after a sense of location, whether that is suggested by what's on-screen, by the recording venue or even the dry, intimate acoustic of many pop/rock studio recordings.
| 5.1 Channel Dolby Digital/Dolby Pro LogicII |
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| Fig 1. Standard Dolby Digital 5.1 / DPL II Setup |
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| Dolby Digital EX/Dolby Pro LogicIIx/7.1 channels |
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| Fig 2. Dolby Digital EX 6.1 and Dolby Pro LogicIIx 7.1 channel Setup |
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| Fig 3. Suggested Corner Arrangement of Dolby Digital 5.1 Channel Setup |
Let's deal with the standard Dolby Digital 5.1 setup first (fig.1) since it represents the mandatory standard for current DVDs and for High Definition TV broadcasts. Assuming you are centered in the middle of your couch, facing your TV display and center-channel speaker at 0 degrees, then your left and right main front speakers should be within a 22- to 30-degree angle to each side, viewed from your seat.
The main left and right surrounds should be to the respective sides of the listening area, above ear level if possible (2 - 7 feet) at an angle of 90 to 110 degrees from the front center. Fig. 3 gives you suggestions for corner setups.
Increasing numbers of movie soundtracks are encoded in Dolby Digital EX, which adds a sixth mono channel at the back. Although a mono channel, the back channel is better realized by using two rear speakers, at angles between 135 and 150 degrees to the front center (fig. 2). Directly behind you would be 180 degrees from the front center, and that isn't recommended because of how our ear/brain interprets sounds originating from directly behind us. We sometimes confuse such rear-emanating sounds and place them in front of us. This dual-rear arrangement also serves perfectly for Dolby Pro LogicIIx (7.1 channels), which synthesizes separate Left Back and Right Back signals for increased realism and more dramatic rear/front or front/rear flyover effects.
Subwoofers
Since deep bass isn't directional (the sound travels in every direction, not just where the subwoofer is pointing), the subwoofer can go just about anywhere on the floor, but corners will give you the greatest enhancement of deep bass, at the risk of it sounding boomy. Moving a subwoofer or a floorstanding full-range speaker away from any intersecting room boundary will reduce the tendency to boom or to have too much bass. In either case, you will have to experiment to achieve smooth and extended deep bass. Adding a second subwoofer will help smooth out the bass for all listening locations. Look in the A/V Tips and Axiom Digital Library for more detail on subwoofer placement tricks.
If your room doesn't look like any of the examples above, send your room layout to our team of audio experts and they'll be happy to help you!
