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Chapter 4. Playing with Hardware >  Place Your Speakers Properly

Hack 39. Place Your Speakers Properly

With the right home theater equipment chosen ( [Hack #38] ) and in hand, your next step to great console gaming sound and video is connecting everything. This can be quite complex, but following the following guidelines will lead you to success. Here's how to connect your audio equipment for the best possible experience.

4.6.1. Check Your Wiring

When first setting up or reviewing a system, start by checking the wiring. Don't be afraid to disconnect everything. While you're verifying your connections, you have the chance to straighten and untangle your wires. Do it! This is a great time to label all of your system wires. Do it! You can buy small plastic labels, but masking tape works fine. You'll feel better about your system if everything is neat, labeled, and connected correctly.

To avoid confusion and tangles, run your components one at a time. To confirm that you've connected the inputs and outputs in the right direction, consider where the signal flows.

If you're connecting a Dolby Digital-compatible component to a DD 5.1 receiver, the receiver's display will often indicate the presence of a 5.1 signal. This helps to determine a good connection.

If you're connecting your console or DVD player to a surround receiver with a Toslink or coaxial digital cable, set the device to Dolby Digital mode in its audio menu. (They're usually set to two-channel analog by default.) Some devices also have a PCM mode. Although this is a digital mode, it supports any two channels, so switch to Dolby Digital to send a 5.1 surround signal to your receiver.

Speaker wires are always marked somehow from one side to the next (positive versus negative). Usually, there is a bit of writing or imprinting on one of the two wires. I follow the writing-equals-negative convention, but you can go either way, as long as you're consistent. You must connect the positive lead to the positive side of the speaker and amplifier. Reversing one of these sets produces out-of-phase sounds that will kill your speakers' imaging properties; one speaker's cone will travel outward while the other travels inward.

Test and setup DVDs, such as the Avia Guide to Home Theater (http://www.ovationmultimedia.com/), allow you to determine correct wiring through sound checks, but it's easier to do things right the first time.

4.6.2. Speaker Placement

Unlike subwoofers, which play sound frequencies so low that the human ear can't determine the speaker's location, normal full-range audio speakers readily reveal their position. It's important to place your speakers in the right spots and position them correctly.

The main two left and right speakers should form an equilateral triangle with the prime listening position, directly front and center of the screen. In other words, the viewing distance from the speakers to the front row of seats should equal the distance between the speakers. Point your front three speakers directly at this position, as precisely as possible.

Some people use masking tape or even fancy laser devices to make a perfect triangle and correct their aim. You can do well without that work, as long as you understand that you won't have much imaging if your speakers fire directly ahead into your couch.

You can improve the sound of your system quite a lot by reaiming your speakers. This is the best free tweak I can tell you about: do this right away. Align the main speaker's tweeters at the height of your ears in your seated listening position. If your speakers sit on the ground and fire into the furniture, raise them to the correct level. You don't need expensive stands; just be creative and set your speakers at a better height.

This advice also applies to the center-channel speaker. Wherever you have this speaker mounted, point the tweeter directly at your head when you're watching a movie or killing zombies. Use an empty CD case or two AA batteries taped together to tweak the center channel up or down correctly. Surround sound speaker placement

Surround speakers are more complicated. Many new formats benefit from specialized setups. Some receivers even have provisions for multiple types of speakers that deploy under certain conditions. I'll concentrate on the bread-and-butter Pro Logic and Dolby Digital 5.1 formats used by consoles today. In a perfect world, you'd own dipolar surround speakers, which help create a null area of no sound from the cabinet sides. By design, they fire equally to the front and rear to mimic a movie theater's surround array, creating an enveloping sound field at the rear of the room.

Many people simply use a spare pair of small speakers for surround channel sound. This is fine until you can upgrade to a set designed for home-theater use. These speakers produce unidirectional sound. You can spread this out by reflecting it into a corner first, instead of directly at your head, like the front three. You may like it this way a lot more, especially for movies. This method will create multiple reflections that will approximate a dipolar speaker, but you'll need to experiment a bit with positioning.

If you listen to a lot of multichannel music, you may appreciate a configuration in which you can switch back and forth between reflected and direct-fire modes. If you have the space, place the speakers themselves above and behind the prime listening position by about three feet in each direction. If your couch is right up against the back wall, at least put them to the sides, not in front of the couch. The corner trick applies here as well.

You can reinforce the bass output of your main speakers greatly by putting them very close to the walls or corners of the room, but this placement will affect only one or two frequencies, according to the dimensions of your room. This kind of bass reinforcement sounds muddy if the speakers are too close together and isn't very pleasing to the ear in the long run. Pull each of your front speakers at least a couple of feet out and away from the side and front walls if possible. Rearrange your room

One of the biggest factors in your sound setup is your room and its orientation. If you can't position your speakers as I've described, consider a room makeover. Some people insist on placing the TV in the corner of the room, which is a nightmare for sound. Aligning the sound along a diagonal axis makes reflection problematic, volume inconsistent (especially bass), and imaging poor overall. Set up the screen and speakers on the square axis of the room—along a main wall instead of the corner—to maximize the potential of the room to reinforce the speakers' loudness and bass.

4.6.3. Reducing Noise

You will find that 60-Hz noise is inherent in and around AC power line cables, so people commonly want to reduce it. Start by routing the AC lines away from the interconnect cables as much as possible. Especially avoid running them parallel to each other! I've found that bunching the AC lines together does cancel out noise somewhat.

Hands down, an incorrectly wired subwoofer is the biggest hum and noise generator. This often comes from a ground potential difference. In short, the subwoofer connects, via a grounded plug, to a different outlet than the main system, and the differences in the ground wire lengths cause a hum. One easy fix is to defeat the subwoofer's ground altogether with a ground cheater plug, though it may leave you open to damage.

If you are experiencing ground hum from another source, such as cable or a satellite connection, try running a separate ground wire to reground coaxial cable lines. The best place to do this is from the splitter, because there are often ground wire connection screws. If this doesn't do it, you will need an isolation transformer (available at Radio Shack). See the Curing Ground Loops site (http://www.siber-sonic.com/broadcast/GLoopFix.html) for more information.

Do-It-Yourself Grounding

Attach your ground wire to a cold-water pipe, not a gas pipe. I know it seems elementary, but please, please check thoroughly. Attaching to the house's main ground rod is your best option, because it will eliminate ground potential differences. The outside surface of the fuse box or circuit breaker is also an acceptable bonding point.

If this kind of home wiring sounds complicated and dangerous, that's because it is. If you are not comfortable with this kind of work, you should call in the cavalry: a licensed professional electrician.

4.6.4. Hardware Settings

Now that you have everything wired, placed, and grounded correctly, let's talk about hardware settings. Even though I fly solo on Christmas morning when I put together my little nephew's Lego set, when it comes to my gear, I read the instruction manual to save myself time and frustration. Do the same for your surround processor and TV.

People often overlook the bass management setting in their surround processors. Dolby Digital systems have different speaker settings, including Large and Normal (or Small). This affects the bass output of the receiver and the bass load it places on the speaker. Bass management is smart enough to reroute any bass you take out of the center channel to the main speakers, subwoofer, or both. Remember to set the speaker profile to match your system.

Large center channels are still rare, though growing in popularity, so check your speaker's specs to see if it can handle loads below 80 Hz. If not, set it to Small. The same rule applies to your surround speakers and subwoofer. The sub setting has three modes: off, on, and both. Use "both" when you have large mains that can also handle deep bass and a subwoofer. The low-frequency effects (LFE) channel is the .1 in 5.1; it's automatically routed to wherever you have sent these bass signals. If you don't have a sub, set your subwoofer to "off/no" to route the LFE signals to your mains instead. Subwoofer settings

The subwoofer has settings on its back panel to help determine its location. First, wire your sub with the line-level or single interconnect (RCA) wire to take advantage of the receiver's digital bass processing. Your sub might also have speaker-level connections—actual connectors for speaker wire inputs and outputs—but this is a very inefficient and costly way to connect your sub.

The sub may also have a "crossover" setting on the back to determine where it starts to reproduce the bass signal. Ideally, you'd like it to pick up where your main speakers leave off. To set this correctly, you'll have to find where the speakers stop producing a strong bass signal. Usually, you can find this in the documentation, but magazine reviews from reputable publishers are also great sources of independent and unbiased information.

If your mains roll off at 40 Hz, set the sub for about 40 Hz. If they're small, play with settings from 80 to 120 Hz. It may sound complicated, but it is really that easy. A little time spent experimenting will pay off in the long run.

Let's talk about placement again. Consider where you set the sub to start making bass. The lower the frequency, the less directional the signal is. Not all subs can go this low; if you have smaller main speakers, you'll need to make more mid-bass at higher frequencies. The higher the frequency, the better your ears can locate it.

If you have your sub set up to complement smaller speakers by producing higher-frequency (mid-bass) sounds, you're better off placing it in the front of the room near the mains to reinforce them. This way, the entire audio spectrum will sound as though it all comes from the main speakers. If your mains don't need reinforcement, and the sub reproduces only the low-frequency channels from about 20 to 80 Hz, feel free to experiment by placing it anywhere in the room. For maximum effect, I recommend first trying a spot closer to your listening position, perhaps just to the side.

Finally, let's discuss level settings. Again, in a perfect world, you'd have five speakers with identical sound properties and matching timbre. When you don't, it's impossible to control the volume precisely because the sound character changes so much from speaker to speaker. One of the best investments you can make is an analog Radio Shack sound pressure level (SPL) meter. This tried-and-true device will help you dial in the perfect volume level for each speaker. Using the test tones from the receiver, you can equalize the speaker volumes with accuracy not possible using your own ears. This makes for smooth transitions around your room and maximizes your immersion as sounds fly from speaker to speaker.

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