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Optimizing Front LCR Speaker Placement, Configuration and Performance

by July 20, 2015
Triad Speakers Closeup

Triad Speakers Closeup

originally published: 2/23/15

Random tips, hints, musings, and thoughts from a grizzled industry veteran

Integrating main loudspeakers into a home will always involve at least some compromise. Even a dedicated home theater or two-channel venue will mandate some give and take, maintaining balance between sound quality, aesthetics and other variables. Let’s assume here that we’re concerned with rooms where music and/or movies will be the primary activity, rather than rooms where sound quality is incidental.  Subwoofers and surround speakers deserve their own dedicated articles, so we won’t be discussing them here. I hope these thoughts on integrating front speakers are helpful…

Buy the best main speakers you can afford.

Hopefully, you’ve selected appropriate speakers for your particular application. Once again, we have the inevitability of compromise. I can’t stress strongly enough that you should buy the best main speakers you can afford, short of donating an organ or cashing in a term-life policy, because speakers determine the sound quality of your system about as much as any other factor. (The other two most-important factors are room acoustics and program material.) Once you choose your speakers, choose the proper amplifier or receiver to drive them. Match the speakers to the room; match the amp to the speakers. 

Front 3 LCR Speakers Triad

Matching Front Triad  InRoom Gold Monitors (left, center, right)

 

 Optimizing Front LCR Speaker Placement YouTube Video Discussion

 
When placing speakers, symmetry with the listener is important.

When positioning speakers, symmetry with the listener is important. If at all possible, be seated at the same distance from the left and right front speakers. In a two-channel system, many manufacturers recommend an equilateral triangle, with the left speaker, right speaker, and the listener at each corner of the triangle. I prefer this configuration for stereo listening, but it isn’t always practical. You may also want to toe-in the speakers, as many speaker companies recommend. I’ve experienced good results, depending upon the particular speaker, with aiming the speakers directly at the money seat, aiming the speakers at a point about three feet behind the money seat, or even having the speakers face straight ahead. Some speakers are as much as 3 dB hot in the treble on-axis and meant to be positioned facing directly forward. Consult the manufacturer and do your own experimenting. With the majority of speakers, there is only one “best” listening position, in the center. Secondary seats are more of a compromise, and friends or family members who are ambivalent about sound quality should be banished to these seats. There is one caveat on symmetry: Avoid placing a speaker where the woofer will be the same distance from the floor, side, and/or back wall. This will cause the piling up of “bounce” in the bass, resulting in peaks and nulls. Asymmetry is preferable here.

In a home theater with multiple speakers and multiple seats, placement issues are somewhat different. You still want symmetry, especially with the front three speakers. And then there’s the physical disruption known as the video display. More about that elephant-in-the-room in a minute.

Because of the surround speakers in a home theater, and because of the processed or encoded surround signal, a wide enveloping soundstage can be created. Side surrounds are often fed information that has been mixed hard to one side, and the perceived image will be to the left of a left front or to the right of a right front speaker. Surrounds create a wider image, and because of this, your front speakers’ physical separation may not have to be as great. What is more important is having the left and right front speakers positioned where the sound will correspond with the visual cues on the screen. The left and right fronts should be positioned in proximity to the edges of the video display or screen, especially if the video display is large. If you have a 60” television in a room that’s 16’ wide, the last thing you want to do is have the left and right speakers in the front corners. The soundstage will be exaggerated, too wide, and not tied to action on the screen.

Probably the biggest compromise in speaker type and placement in a home theater is often unavoidable. I am speaking of the dreaded “horizontal center channel speaker.” Nearly all horizontal centers, even the better ones, have the wrong dispersion pattern. When the drivers are horizontally configured, the speaker tends to have narrow horizontal dispersion and broad vertical dispersion; the opposite of what is ideal. People sitting 45 degrees off axis will notice reduced high frequencies and a lack of detail and clarity. The higher the frequency, the more an audio signal will “beam,” like a flashlight. There are a few ways to ameliorate this, but they usually involve spending more money. The best way to deal with this dispersion anomaly is to vertically configure the midrange and tweeter…

See: Horizontal vs Vertical Center Channels and Horizontal vs Vertical Center Channels - Alternative Perspective

Placing a speaker under a screen is never ideal and can be especially problematic for viewers in multi-row seating.

There are center channel speakers with multiple horizontally-configured drivers that also have a vertically-aligned array consisting of a midrange driver and tweeter. This doesn’t solve all the problems, but it improves off axis response by having a better horizontal dispersion pattern. A few larger center channel speakers have been designed with a vertically-aligned mid/tweet/mid array. This configuration yields wider horizontal dispersion and controlled vertical dispersion that is similar to vertically-aligned left and right speakers. As a footnote, your center speaker ideally should be the same brand and series as your left and right fronts, for consistent performance, smooth pans, and similar voicing.

A mistake I’ve noticed (with appalling regularity) is the use of a horizontally-configured center channel speaker under a video display in a room with elevated second or even third rows of seating. The ideal level for a tweeter is around 40”, or at typical seated ear level. Placing a speaker under the screen is never ideal, and that problem is exacerbated by having viewers in the second row an additional 8” higher. It’s not uncommon to see a home theater where the tweeter in the center channel speaker is aimed at the listeners’ ankles and blocked by the first row of seating. As I look at pictures of high-end custom theaters in professional A/V publications, I see this all the time.

Front 3 LCRs Triad

Front Three Matching Triad Gold Monitors

The solution; and not an especially inexpensive one; is to use three identical front speakers positioned at the same height with at least the center (or all three) behind an acoustically-transparent screen with a front projector. This configuration absolutely nails the action and dialogue to the picture being displayed. A center-channel version of a speaker, even with the same drivers, will sound different due to its (lower) placement under a screen. Even an absolutely identical speaker (placed vertically) under a screen will have a different sonic character because of its different placement than the left and right speakers.

Front Triad w Screen

Front Three Matching Triad Gold Monitors at Same Height with Motorized Drop Down Screen

There are reasons cited not to use an “AT” screen, many of which are incorrect and based upon the state of the technology when it first appeared years ago. Sometimes installers will eschew an AT screen because of fear of audio degradation, not thinking that placing the speaker below a fixed screen degrades the sound much more. A proper modern AT screen will drop the audio level no more than 1.5 dB above 5–10 kHz, and the audio is not degraded. I have heard perforated screens work well, but typically they require more EQ than a woven screen, and there’s more audio loss. Newer woven screens also offer excellent video quality that approaches the quality of solid screens. I have recently read about fabric screens that tout their ability to work with 4k projectors, although I have not yet seen the combination. Because the center channel often carries 60% or more of the front soundstage, a center channel speaker shouldn’t be trivialized. It’s important, and if you want the best soundstage, you might want to consider a projector and acoustically-transparent screen. The quality of acoustically-transparent screens and excellent projectors has improved immensely and come down in price dramatically over the past decade, so this solution is often within reach for us commoners.

Pulling speakers out into the room sounds better because of the higher ratio of direct to reflected sound it produces.

The conventional wisdom of most audiophiles (and, yes, I are one) is that front speakers will sound better if they’re pulled way out into the room. They will sound better, but not because they “breathe,” or necessarily because they have more space around them. They sound better closer because 1) the ratio of direct to reflected sound at the listening area is greater, and B) they’re simply louder when they’re closer. Every time you double the distance away from a speaker, the level drops approximately 6 dB (3-4dB in reflective rooms, 6 dB anechoic). This is known as the Inverse Square Law. With line source or planar speakers, that drop is less, more in the neighborhood of 3 dB-4.5 dB. There are some excellent high-end in-wall speakers for those of you who want a stealth installation, but because they’re farther away from the listener, they may have to be pushed harder. You can overcome these two issues with more power and with acoustical treatments to damp reflections. Treating your room is a whole other topic, but you can dramatically improve the focus of your sound by killing first reflections with acoustical panels adjacent to the baffles of your left and right front speakers, especially if your room is narrow and the speakers are close to the side walls. The “mirror technique” is very useful here. A reflected signal mixed with the direct signal causes a blur and lack of focus due to the signal reaching the listener a few milliseconds later in time. By definition, this is distortion and should be eliminated. Without an engineered acoustical treatment solution, I would at the least recommend acoustical panels next to and behind the speakers on the front wall to help kill the reflections from the midrange and lower, and using carpeting and padding on the floor. Hardwood floors are lovely, but they don’t work well for audio. You want your room to “reproduce” sound from the source and not “produce” sound by mixing room reflections, decay, and slap echo into the audio.

Conclusion

Hopefully, you've selected the best front speakers you can buy, you've appropriately treated your room, you have positioned your video display (or screen) properly, and you have adhered to some of these tips for placing your front speakers optimally. With some common sense, pragmatism, and attention to detail, you can greatly enhance the enjoyment you'll get from your components and your room. And isn't that the reason we do this?

Please share pictures of your home theater LCR set up in our related forum thread and let us know what compromises (if any) you had to make in your layout for it work in your particular listening space.

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