August 2003

Speaker Choices for Home Theater

People who want home-theater systems but who aren’t necessarily big-time hi-fi enthusiasts often get railroaded into a particular type of home theater by whoever has them in their sights. These people end up with a home theater, but it might not be what they were hoping it would be. Stereo enthusiasts may want to have a home theater the whole family can enjoy, but the room has to remain functional for other uses as well. Whether you’re an enthusiast of good sound or not, you can influence the ultimate performance and satisfaction of your home-theater system if you understand the range of speaker products that are available to you.

There are three major types of speakers you find in home-theater systems: in-wall speakers, on-wall speakers, and conventional freestanding speakers. In-wall speakers have the guts of the speaker inside the wall cavity, with a grid or grille that fits flush with the wall. On-wall speakers mount on a wall using a special type of bracket that is included with the speakers. Conventional freestanding speakers are placed well away from walls -- like traditional stereo speakers.

Conventional freestanding loudspeakers

Most everyone is familiar with these from the "stereo" days. Freestanding speakers offer the best sound quality and the best bang for your performance buck. You can put them anywhere in the room and turn them toward or away from the listeners. Speaker cables can be laid on the floor, so there’s no concern about installation in walls or under carpets. Conventional speakers are the most portable -- you can pick up your speakers and move them to your next home rather than having to leave them behind.

Installation is simple enough for most people to do by themselves. If the speakers are small, you’ll need an appropriate stand or other supporting surface to hold the speakers. Most people won’t run really good speaker wire in the walls of their home, but many will purchase good-quality speaker wire for their conventional speakers, knowing that, when they leave, they can take with them not only the speakers but the wires as well. The quality and construction of the speaker cable does affect the sound you hear -- not as much as some other factors, but it is a detail that should be dealt with appropriately. In this case, "appropriately" is almost always tied to a budget.

In-wall speakers

About the only reason for the existence of in-walls is the fact that they are the most invisible speakers available. For many, that single characteristic overrides all their shortcomings. In the last five years, a staggering variety of in-wall speaker designs have emerged -- everything from seven-foot-tall panel speakers, to amplified conventional speakers, to models with drivers mounted on pivots so they can be aimed as needed. Your choices need not be limited to bottom-of-the-barrel, "contractor grade" in-wall speakers; you can do much better than that.

Spouses and decorators are responsible for the sale of more in-wall speakers than any other factor. Non-enthusiasts love in-wall speakers because, unlike conventional speakers, they can be made almost invisible. Many in-wall speakers come with paintable grilles so that they can be matched to the wall color for near-perfect camouflaging. The wires for these speakers are usually run through walls, which keep wires off the floor and out of sight.

However, technical issues with in-wall speakers compromise their sound when compared with similarly priced conventional loudspeakers. It’s difficult to design a good-sounding speaker with a large front baffle -- the flat surface the drivers mount to. Some of the best-sounding speakers money can buy strive to make the front baffle as small as possible. When the speaker is mounted in the wall, the entire surface of the wall becomes part of the front baffle -- exactly the opposite of what some believe is a condition critical for quality sound.

The stud walls and wallboard or plaster in your home were not designed to be good loudspeaker materials. When you mount in-wall loudspeakers to wall studs, the speakers will cause the studs and wallboard to resonate at certain frequencies. This resonance was not part of the original recording, so the sound you hear in the room will be altered to some degree. Some of the better in-wall speakers include installation materials designed to isolate the speaker from the studs and wallboard, to minimize the resonance transmitted from the speaker to the walls themselves. This is definitely a step in the right direction.

The least-expensive class of in-wall speakers has an open-back design that relies on the wall cavity to make five sides of the speaker enclosure. Open-back in-wall speakers transmit the most sound and resonance to the wall. While this cheaper type of in-wall speaker tends to have poorer sound quality, the lower cost makes it perhaps the most common in-wall design used by builders in new construction, where the main goal is keeping the price of the sound package low.

Some in-wall speakers are semi-sealed, which means they may have a port that vents into the wall cavity. The rest of the speaker is closed, so midrange and high frequencies don’t leave the speaker through the back and sides; only bass frequencies pass through the port into the wall cavity. The port will extend the bass response of the in-wall speaker at the expense of exposing the wall materials to those bass frequencies. That will cause some resonance, but they will be low-frequency only. This is definitely preferable to full-range sound being projected into the wall cavity.

A sub-set of the ported in-wall speaker places the port on the front of the speaker so it fires into the room rather than into the wall cavity. This type of design has the advantage of extending the bass response of the in-wall speaker without introducing bass energy into the wall cavity. Careful design of this type of speaker can avoid bass-cancellation problems that could come from having the woofer and the port on the same side of the speaker.

The final type of in-wall speaker is the sealed enclosure -- similar in construction to a ported speaker, but without a port. This type of speaker should sound the best, but they tend to cost the most and have the least amount of bass power and extension for the money, even if the bass they do reproduce is arguably the best quality of all three types of in-wall. You can go for a somewhat larger sealed speaker to get deeper bass response, but that will increase the speaker’s cost.

If you live in a very cold or very hot climate, you may want to consider not installing in-wall speakers in any outside walls. The speaker will displace some or all of the insulation in the part of the wall it will occupy. This will expose the speaker itself to very cold or very hot temperatures, and the drivers used in loudspeakers do not perform well when not kept near room temperature. Because wall insulation is partially or completely displaced by an in-wall speaker, there can be problems with condensation and resulting water damage -- to the wall, the speaker, or both. If in-wall speakers must be installed in an exterior wall, you should ask all kinds of questions about how the installer will prevent the various problems that can be caused by "holes" in the insulation. Remember -- just because someone has installed 100 in-wall home-theater or whole-house sound systems doesn’t mean they actually know what they’re doing. Installation of in-wall speakers adds significantly to the cost of the speakers -- something people tend to underestimate.

There isn’t space in this column to completely address all of the issues involved in positioning in-wall speakers for the best sound. But placement is very critical for in-walls -- except for some limited aiming available in a few models, once installed, an in-wall can’t be rotated or tilted. Not only that, in-wall speakers will lock you in to a single furniture arrangement. If you want to rearrange the furniture, your entire setup could become unbalanced. If your designer didn’t know that the couch needed to be two feet farther back, your in-wall speakers could end up being installed in the wrong locations. You’d still get sound, just not the sort of sound you thought you paid for when you bought your home-theater system.

On-wall speakers

On-wall speakers are a good compromise when there is pressure not to have freestanding speakers, but there is a desire for better sound quality than is possible with in-wall speakers. On-walls don’t require large holes to be cut in the walls; their mounting brackets attach to the wall with two to four fasteners. The speaker is then hung on the bracket, the back of the speaker contacting the wall. Most relatively handy people can handle this part of the installation. Wires can be concealed in the walls, floors, or under carpets. If the on-wall model you choose is paintable, you can match its color to the wall. Like in-wall speakers, you can’t aim on-walls unless the design incorporates tiltable drivers, and most lack that feature. But if you want to rearrange the room, on-walls are far easier to relocate than in-walls.

Most on-wall speakers tend to be sealed-box designs, or perhaps have forward-firing ports to extend bass response. On-walls will have an additional degree of isolation from the walls compared to in-walls. The arrangement of the on-wall speaker away from the wall makes the effective baffle size smaller for high and midrange frequencies. Assuming the on-wall is well designed, that means it will give you better sound than a comparable in-wall. On-wall speakers won’t disturb the insulation in exterior walls, so there are no concerns about condensation, or the speakers getting too hot or cold from being in an under-insulated wall cavity.

Conclusions

If you want the best possible sound quality, the most portability, and the most flexible room-placement options, conventional freestanding loudspeakers are still the best choice. On-wall speakers can be very close to conventional speakers in sound quality, but they offer many of the advantages of in-walls. In-wall speakers are the darlings of the custom-installation business, but there are often issues with them that potential buyers are unaware of until months or years later, when they notice the sound quality is not that great, or discover that condensation has damaged a wall or speaker.

 ...Doug Blackburn
db@hometheatersound.com

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