Dolby Laboratories Home Theater Speaker User Manual

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Home Theater Speaker Guide

Optimize your sound system that includes Dolby® technology with this step-by-step guide to

the best speaker setup, including room considerations and other valuable tips.

90º

110º

22º 22º

30º 30º

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110º

2.1

5.1

2 Speakers

5 Speakers 1 Subwoofer

1 Subwoofer

5.1-Speaker Room View

1. Seating Position

2. Left and Right Speakers

3. Center Speaker

4. Left and Right Speaker Angle

5. Subwoofer (the “.1”)

6. Left and Right Surround Speakers

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Fine-Tuning

Once you’ve done your basic speaker setup, you’re ready to enjoy the home theater

entertainment experience. Keep in mind, however, that every room is dierent; you may

be able to further improve the sound by going beyond the general guidelines and ne-

tuning the speaker placement within your room. You could, of course, hire a professional

installer; however, with just a little time and some careful listening, you can do it yourself.

Your Environment

An Ongoing Experiment

There is no objectively “perfect” setup. All speakers, no matter how good, are bound by

the laws of physics. What you can do is put them in the best locations to take maximum

advantage of their capabilities, both individually and within the total system. Remember

that the best sound is what sounds best to you. It’s your system. If you’ve set it up and it

sounds great, you may not need to read any further.

However, if you’re not hearing any bass, or there’s no sense of spaciousness and depth, or

something seems to be missing, some ne-tuning may be in order. Even small adjustments

in placement can have clearly audible eects. And that goes for your furnishings as well

as your speakers.

First, do some extended listening. Do you hear a convincing sonic “image” between

your main (front left and right) speakers? This is the soundstage, and you want to

maximize it for depth and richness. Ideally, the speakers will “disappear,” and the sound

will ll the space between them. Focus on dierent types of sounds—voices, motion,

music, sound eects—in turn. Individual vocals or instruments, or eects such as

footsteps, should be precisely placed across this space.

Now try positioning your main speakers farther apart and then closer together and listen

to the results. Move the speakers in small increments, a few inches at a time. Generally,

the greater the distance between your main speakers, the wider your soundstage; the

closer they are, the more centered the sound. If the speakers are too far apart, they will

start to sound like separate speakers rather than a coherent system.

Similarly, when ne-tuning the placement of the surrounds, keep the idea of the

coherent system in mind. Surround sounds should emanate from within a general area

(covering the sides and rear of the room). Even if the surround sounds can be localized,

the localization should be from within this overall area and not just from an individual

speaker. The sonic image should be a single entity or environment.

Many of the more full-featured A/V receivers include a calibration microphone and can

generate test tones for each speaker individually, then automatically calibrate distance,

levels, and other settings. An increasingly popular receiver feature goes further, providing

full and automatic room equalization. These features greatly simplify setting up your

system properly.

Be aware of standing waves in your room, which are caused by sound waves reecting

o the walls. Because the reections can overlap, the waves will cancel each other out at

some spots (dips or null points) and reinforce each other at dierent spots (peaks). All

rooms have standing waves, and they’re most noticeable at low frequencies in smaller

(and especially squarer) rooms. Play some music with strong, steady bass, and walk

around the room. If you hear very little bass in some spots and lots of it in others, then

you have a standing-wave problem, and you want to be sure that your listening spot

HOME THEATER SE TUP GUIDE

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is not in a peak or dip. If it is, rst try moving your subwoofer—even a few inches can

make a dierence. Similar shifts in the main speakers, or in room furnishings—even

moving your listening spot—may help.

Let Nothing Come Between You and Your Sound

You want a clear path for the sound between your speakers and your listening position.

If you have furnishings blocking your view of the speakers, you can be sure they’re also

blocking sound. The only exception here is the subwoofer, whose low-frequency sounds

are omnidirectional and do not follow the “line of sight” rule.

Room Geometry

Room shape, ceiling height, and ooring material all contribute to your room’s acoustics,

its unique sound signature. While you probably can’t redesign or rebuild your room,

there are some things you can do to make the most of it.

First, try to minimize the areas of bare walls and oors, although that doesn’t mean

you need to cover every square inch. Keep the aesthetics of your room and the sound

benets of wall and oor coverings in balance. The idea is to have as much of the sound

as possible reach your ears straight from the speaker—not from o your oor and walls.

Reected sounds reach your ears together with those coming directly from the speaker,

reducing clarity. So the placement of rugs and wall coverings is as important as their

coverage. Also, furnishings don’t have to be soft and absorbent to minimize reections.

Bookshelves, for instance, can serve the same purpose by diusing reections.

Some of the biggest acoustic problems are caused by rooms that are perfectly square

or have one dimension exactly twice another. These are the geometries that tend to

generate standing waves that cause clarity and level issues. If this describes your room,

you may need to perform extra experimentation with speaker and furniture placement to

defeat the geometric odds.

The Multipurpose Home Theater

If, like most of us, your home theater room also is your living/family/workout room,

then you may have to make a few allowances for your speakers. But sound can still be a

top priority.

To avoid shaking and rumbling the whole house or disturbing your neighbors, you

can place your subwoofer on rubber, dense foam, or neoprene pads to isolate it

from the oor. (Many companies sell pads and platforms specically for subwoofer

isolation.) Also, make sure all your speakers are far enough away from intersecting

room boundaries (wall and ceiling, wall and oor, and especially corners) to reduce

“boom”—these areas naturally reinforce bass frequencies.

To ensure a home theater experience that isn’t dominated by dramatic sound eects at

the expense of dialogue clarity, be sure to set the proper volume level for your center

speaker. Turning up the overall volume to compensate for dialogue that’s too soft will

often overpower you with everything except dialogue. Most movies and TV shows are

mixed with the bulk of the dialogue in the center channel, and proper level setting will

keep it loud and clear.

All in all, your home theater can deliver great sound while still accommodating the other

activities in your home.

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A Bit About the Visual

Audio’s not the only part of your home theater you’ll want to calibrate. Most TV sets

will need calibration as well. Most TVs have been factory calibrated to look good in a

retail showroom, whereas your lighting conditions and preferences are likely to be very

dierent. Your furniture and decorations aect how you see your TV picture, too, so it’s

important to calibrate your visual settings—like brightness, contrast, and colors—for

your room. As with audio, this can be done by a professional installer, for a fee. For much

less, you can buy a calibration DVD to help you. These are available from a number

of dierent manufacturers—ask your A/V equipment retailer or check the web. This

calibration will probably take half an hour to an hour, which will be time well spent.

For the optimum viewing experience, check out the recommended viewing distance for

various screen sizes and resolutions when choosing a TV set. Most manufacturers oer

guidelines on this.

Basic Speaker Math

Five from Two

Even if most of your TV and music is in stereo, you can still take advantage of a multichannel

surround system using all your speakers, thanks to Dolby technologies. Enable Dolby Pro

IIx for your stereo content (there’s usually a control for this on your receiver), and

Logic

you’ll hear very natural surround sound. Dolby Pro Logic analyzes the stereo signal and

creates the surround channels based on directional cues in the signal.

Distribute Your Frequencies Properly

If you have a subwoofer, don’t ask your other speakers to try to reproduce low-frequency

bass. Receivers with Dolby Digital technology can be set for “large” or “small” speakers.

Set it for “small,” and the subwoofer to “on.” Now the bass frequencies will be sent only

to the subwoofer, and your sound dynamics will open up as your other speakers are freed

from reproducing low bass.