A. Speakers perform best when the listener's head is directly in front of the speaker and at the same height as the drivers. The sound response where the driver is pointing directly at the listener is called the on-axis response. When you move off-axis (to either side or a different height), the speaker will not sound as loud.

A. The rear speakers in a home theater system have a greater diffusion than you would get with stereo speakers. Sometimes, rear speakers have drivers firing in multiple directions. This causes a lot of reflection against the walls and makes the rear echoes sound like they are coming from a wide area.

A. The center channel is the most important speaker in a home theater system. It produces all of the voices that come from actors on the screen. Without a center channel, the voices would be coming from the corners of your room.

A. Years ago, the word subwoofer meant a speaker that produced sounds deeper than a regular woofer. A subwoofer driver would have to be at least 12" wide to produce these frequencies. Now, the term has come to mean the largest driver in a system, regardless of whether the system has a woofer or not. In some small speaker systems, especially computer multimedia systems, a subwoofer can be 6" or smaller. A subwoofer of this type is completely useless in a good home theater system.

A. Some people believe that you must have the same exact speakers for your front and rear channels, with a center channel using shielded versions of the same drivers minus the woofer. Although this is an ideal situation, it is expensive when the speakers are full range. When using smaller speakers for the fronts with a powered subwoofer, it might be a good idea to get 4 of the same speakers. If not, you will still want to get all of your speakers, with the exception of the subwoofer, from the same manufacturer. Make sure that are designed to work together as a home theater set. Usually, this means they use the same drivers for the mids and highs. This gives the speakers the same sensitivity and sound quality.

A. Dolby Surround and Pro Logic use 4 and 5 speakers respectively. Surround Sound adds rear speakers to the main front pair, and Pro Logic adds an additional center channel. Although these systems use 4 or 5 speakers, the original input signal is still 2 channels: left and right. The 5 channels of sound are encoded into these 2 channels, stored on disc or tape, and then decoded by the home users Dolby decoder. This encoding is done to maintain backward compatibility with older 2 channel systems. A Dolby encoded source will still play correctly when using only 2 speakers without a decoder. The rear and center channels in a surround or pro logic system are not full range. The standard bandwidth for rear speakers is 70Hz to 8kHz, although some soundtracks will contain information as low as 50Hz.
Dolby Digital 5.1, also know as AC-3 because it is Dolby's 3rd audio code, uses 5 separate channels for encoding the 5 speakers, plus 1 separate channel for a subwoofer. The .1 subwoofer channel is for LFE (Low-Frequency-Effects), and is basically a deep bass channel. The 5 main channels will all have a full range signal. Most Dolby Digital processors will have a function that allows the bass from the 5 main channels to be redirected to the subwoofer if desired. This allows for having bass in a system even when using small surround speakers.
Dolby Digital 5.1 encoding is used primarily in DVDs and newer Laser Discs. There are other mediums that use a 2 channel Dolby Digital format, such as CDs, TV satellite, digital cable, video games, and older laser discs. Although it is Dolby Digital, it is not the 5.1 encoding. The 2 digital signals are decoded into a 4 channel surround sound signal. This is used by companies that use a digital signal to save bandwidth or increase quality, but have not yet upgraded to the full Dolby Digital 5.1 system. Dolby Digital does not necessarily mean 5.1 encoding.

A. When Dolby Surround and Pro Logic came out, the typical home theater receiver had less power for the center and rear channels than it did for the fronts. Since the rear speakers were not full range speakers, this wasn't much of a problem. With Dolby Digital, all 5 speakers have their own full range channel. Many recordings are now designed for systems that have the same power for all 5 speakers. It is suggested that you get an amplifier with equal power to all channels.
The subwoofer in a Dolby Digital system usually has its own amplifier built into the sub. Since a single 15" or 18" sub can require 400 watts of power, it makes sense for a sub to have its own amp. Although powered subs come with many features like built in crossovers and polarity switches, a regular sub with a dedicated amplifier can work just as well.

A. The terms bipolar and dipolar both refer to speakers with drivers that are fired in two different directions. With dipolar speakers, the two sets of drivers are on the sides of the speaker aimed in opposite directions and are in reverse phase causing a cancellation of sound waves in front of the speaker. This is usually done in rear speakers that are mounted on the wall, where the front of the speaker is aimed at the listening area. This causes all of the sound to bounce off the walls before it is heard. This makes it almost impossible to determine where the speaker is, causing a true surround sound effect.

A. Ideally, the listening area should be in the center of the room at equal distances from all speakers. If this is not possible, then there are ways to improve the situation. If the listening area is near the back wall, then put the surround speakers high on the side walls facing each other. If dipole speakers are used, then the can be mounted further forward in the listening area and lower on the wall, as long as the front of the speaker is aimed toward the listening area.

A. This is up to the individual's tastes. Most likely, there will be some music that sounds better in a surround mode, and other music that sounds outright horrible. When experimenting with playing music on a Dolby Digital system, try it with and without the center channel.

Televisions LCD FAQs

Q. Is a LCD TV considered a plasma TV? A. No. Both Plasma and Liquid Crystal Television offer slim profiles, but use different technology. Plasma televisions employ neon and xenon gases which are trapped between two thin layers of glass to create a digital image. Plasma TVs usually feature larger screen sizes, so most people put them where they intend to keep them for a period of time. Sharp AQUOS televisions use advanced LCD technology and are the first portable flat screen televisions on the market. This makes it easy to have vivid, crisp television, wherever you want it. Q. What are the advantages of LCD Displays? A. It's easier to watch. Flat  panel TV displays like LCDs and Plasmas are significantly brighter and feature higher contrasts than traditional CRT sets. Which means that an LCD TV will perform exceedingly well under most ambient light conditions. A brightly lit room won't wash out its picture, nor will lamplight cause a glare on your television screen. The beauty of these flat screens is that you don't have to turn out the lights to see the image clearly and easily. Nor do you have to worry about eyestrain, since neither LCDs nor Plasmas flicker the way old-fashioned TVs do. And, you can watch TV from almost anywhere in a room since flat-screen LCD television displays can have up to a 160° viewing angle, which means your TV will look good when viewed from any point 80° in either direction from the center of the display.  One issue affecting the overall quality of the picture reproduced on LCDs has to do with dot pitch. This term refers to the distance between subpixels of the same color in adjoining pixel triads. The closer these "dots" are to one another, the sharper the resolution will be. This is especially true when displaying computer signal images and graphs. And the picture in  front of you will be more realistic and detailed. Higher dot pitches also increase the viewing angles of LCD panels. Since dot pitch is measure in millimeters (mm), a good rule of thumb is this: Smaller dot pitches make for sharper images. You generally want a dot pitch of .28mm [" 10,000 pixels/in2 of your display] or finer. Note: Plasma TV displays have long been touted as having wider viewing angles than comparably sized LCD monitors. But recent improvements in quality have made LCD televisions and monitors comparable to Plasma TVs with respect to their viewing angles. According to Sharp, a leading manufacturer of LCDs, the newest generation of LCD displays have just as good viewing angles as plasma sets, but this is only true of the better brands. In any event, even the best LCD monitors have yet to achieve the breadth of viewing angles found on typical Plasma monitors. You can watch your new television right out of the box because the tuner is included. LCD TVs generally come with tuners and speakers already built in, so they're more or less plug-and-play devices. Since most LCD TVs don't require external tuning devices, they are ideal for smaller applications, where space is at a premium (like bedrooms and small living rooms) or where clutter is inconvenient (like crowed kitchen countertops). Note: Some LCD televisions have outboard media receivers, though many-like Toshibas-don't. Always inquire about extra hardware before you buy: You won't always see your LCD monitor pictured with an external receiver (even if it has one), so it's up to you to find out whether there is any "extra" hardware you need to know about.  The picture is smooth, colorful, and (best of all) wide. LCDs have none of those annoying scan lines that conventional sets do. This owes to the fact that each subpixel has its own transistor electrode, which creates smooth, evenly lit images across the entire surface of the display. It also enables these displays to reproduce images that are saturated with color. [256 shades of red x 256 shades of green x 256 shades of blue " 16.8 million different colors!] Note: All this requires an enormous number of transistors-upwards of 2.4 million for displays supporting a typical resolution of, say, 1024x768. This means that, if there is a problem with any one of these transistors, a subpixel will be affected, which causes the pixel associated with it to fail. Dead pixels will emerge over time and with use. In general, though, the number of dead pixels affecting a given display will be few enough so as to go virtually unnoticed by the average viewer. Recent advances in LCD technology have markedly increased the response time of these displays, resulting in even smoother on-screen presentations. One way to think about response time is in terms of the amount of time it takes a pixel to "refresh" itself-i.e., to go from being active to being inactive, which is to say, ready to be re-activated). Response time is measured in milliseconds (ms), with the best LCD monitors now clocking in with response times under 20ms. Slower response times (>20ms) can cause the image on the panel to lag and appear jerky, an effect known as "streaking" or "trailing." Another phenomenon associated with slower response times is "ghosting." This occurs when the display is made to switch quickly from light to dark states (or vice-versa). In these instances, on-screen images may appear to stay on the screen belatedly. LCD displays come either with a 16:9 aspect ratio (i.e., 16 units wide to 9 units high), the proper one for viewing HDTV and for watching DVDs, or with a 4:3 aspect ratio, the norm for most broadcast television shows. If you opt to go with a widescreen (16:9) display, does this mean that you'll have to watch some shows where the image is distorted or stretched unnaturally? No. When displaying a "normal" or 4:3 picture image from satellite, VCR, or cable TV, the image can be viewed in a number of ways-in its original format (with black or gray bars on the sides of the screen), or in "full" mode (where the image is converted or "stretched" using specially designed algorithms to reduce the visible stretch marks as much as possible). Again, the quality of the picture produced under such circumstances depends largely on the quality of the television with which you scale-up 4:3 pictures or scale-down 16:9 ones. Nevertheless, this is only a temporary dilemma: Since HDTV is shown in widescreen, this is the format of the future for much of broadcast television. The display is multi-functional and long-lived. An LCD is a television monitor, capable of displaying HDTV, regular TV, and home video. It's also a computer monitor. In fact, it can accept any video format. LCD displays typically include inputs for (a) composite video, (b) S-video and component video, and (c) one or more RGB inputs from a computer. Because of the high resolution of LCDs, text and graphics look especially sharp when viewed on them, which makes them the best solution for displaying data and web-based content.  Note: Some LCDs (including many by Sharp) do not come with RGB inputs. If you plan to utilize your LCD display as a computer monitor, be sure to check out the specs of the unit you're thinking of purchasing.  You can expect to use your LCD monitor in many capacities for many years: The average lifespan of one of these displays is 60,000 hours. If watching TV was your full-time job, and you did it 24 hours a day, it would take you almost 7 years to wear out your LCD display. With more normal viewing habits of, say, 8 hours per day, you can extend the lifespan of your TV by a decade or more (to about 20 years)! Note: The lifespan of an LCD display is generally longer than that of similar-sized plasma displays. Some manufacturers claim that their LCDs can last upwards of 80,000 hours when used continuously under controlled conditions (e.g., in a room with "standard" lighting conditions and 77° temperatures throughout). Just how realistic such claims are is debatable. After all, whose living room has no windows and remains at a perfectly comfortable 77 degrees year-round? A more immediate concern is the actual lifespan of the light source in your LCD. This is perhaps THE critical component of your display unit. It is particularly important for maintaining a proper white balance on your TV. As these florescent bulbs age, colors can become unbalanced, which could result in too much red, for example, in your picture. So, it pays to buy name-brand displays. You will definitely pay more for better LCD display brands like Sharp, Toshiba, JVC, or Sony than you will for cheap Chinese or Korean variety knock-offs, but you'll get a backlighting bulb of higher quality and, in the end, a TV whose colors will stay truer longer. In some cases, the warranty for this particular feature can be shorter than for the display as a whole. This means you might have to buy a whole new LCD monitor because the coverage on its backlight has expired. Moreover, some bulbs can be replaced, while others are built in to the unit itself. You should definitely do some research on the backlighting system, how it's configured, and how it's warranted.

Televisions Plasma FAQs

Q. Why go plasma in the first place? A. Because the technology is there. In 1996, the Federal Communications Commission (FCC) enacted legislation compelling the nation's 1600+ television stations to change the way they broadcast their programming-i.e., to start transmitting it digitally. Thus began the rise of digital television (DTV) in America. For now, the FCC has allocated an additional channel spectrum to the media. This has allowed the media to offer digital broadcasts in parallel with their existing analog ones, giving consumers the opportunity to watch regular TV while they make the switch to DTV. Once the transition to digital is complete-by 2009 or by the time 85% of US households get digital feeds, whichever occurs later-the federal government will auction off the original analog channel spectrum. And DTV will be the new standard in broadcasting. Sure, you'll still be able to watch your favorite shows in analog like always, but you'll need to "update" your existing TV with a device that converts digital signals into analog ones. All of which begs the question: Why not just go with the digital flow? Q. What's the bottom line? A. Broadcasters now can offer free, over-the-air television of higher resolution and with better picture quality than ever before. DTV is a reality-if you've got the right TV to see it with. The technology behind plasma TVs has been around since the mid-60s, but the first displays were nothing more than points of light created in laboratory experiments. Recent advancements in high-speed digital processing and high-tech manufacturing processes have made compact, full color plasma displays possible, not to mention increasingly affordable for the average consumer. Q. What exactly is plasma TV? A. Most people know plasma TVs as those unbelievably thin display monitors that can be hung on your wall just like pieces of video art. (To give you an idea of the space-saving advantages of plasma technology, consider this: A 40-inch TV may be two feet deep and weigh upwards of 150 pounds, while the same size plasma display might have a depth of, say, 6 inches and weigh half as much.) But this isn't your average slimmed-down television set. The display itself consists of thousands of "cells," which are individual glass compartments injected with neon-xenon gas suspended in plasma-hence the "plasma" appellation. These cells are the basic elements comprising the picture you see on your TV screen. When the gases are electrically charged, they strike red, green, and blue phosphors. Just like that, an image (which is nothing more than the sum of the aforementioned colored elements, commonly known as "pixels") is born. Q. Besides leaving space enough in your living room for, well, living, what are the advantages of having a plasma TV? A. It's easier to watch. A plasma TV will perform exceedingly well under most ambient light conditions. A very bright light does not "wash out" its picture, nor does backlighting cause a glare on your TV screen. The beauty of these flat screens is that, unlike front view projections screens, you don't have to turn out the lights to see the image clearly and easily. Moreover, you can watch TV from almost anywhere in a room, since flat screens have a 160° viewing angle. The picture is smooth, colorful, and (best of all) wide. Plasma TVs have none of those annoying scan lines that conventional sets do. This owes to the fact that each pixel cell has its own transistor electrode, which creates smooth, evenly lit images across the entire surface of the display. Many of the newer plasma displays also have built-in line doubling to improve the image quality of even low-resolution video signals. And they are saturated with color; some high-end plasma TVs are capable of displaying 16.77 million colors! Plasma sets offer superb color realism and exceptional gradations among colors. In fact, these color-saturated images are what give plasma displays an edge over other types of video displays in the eyes of many consumers. Plasma displays have a 16:9 aspect ratio (i.e., 16 units wide to 9 units high), the proper one for viewing HDTV and for watching DVDs. But most television shows are still broadcast in the more traditional 4:3 aspect ratio, the one that more closely approximates the dimensions of conventional TV sets. Does this mean that you'll have to watch some shows where the image is distorted or stretched unnaturally? No. When displaying a "normal" or 4:3 picture image from satellite, VCR, or cable TV, the image can be viewed in a number of ways-in its original format (with black or gray bars on the sides of the screen), or in "full" mode (where the image is converted or "stretched" using specially designed algorithms to reduce the visible stretch marks as much as possible). This is only a temporary dilemma, of course: Since HDTV is shown in widescreen, this is the format of the future for broadcast television. The display is multi-functional and long-lived. A plasma display is a television monitor, capable of displaying HDTV, regular TV, and home video. It's also a computer monitor. In fact, it can accept any video format. Plasma displays typically include inputs for (a) composite video, (b) S-video and component video, and (c) one or more RGB inputs from a computer. You can expect to use you plasma display in many capacities and for many years: The average lifespan of one of these displays is 60,000 hours. That's about 7 years of 24/7 usage! If watching TV was your full-time job, and you did it for 16 hours a day, it would take you more than a decade to wear out your plasma display. Q. What do you need to consider before you buy your plasma or flat screen TV? A. Determine the right screen size based on the floor plan of your home-entertainment room. Plasma monitors are measured diagonally across the screen, just like any other television set. You can typically choose from the following sizes: 42", 50", 60", or 71". Bigger is not always better, especially when you're buying a plasma display to serve as the focal point of a home entertainment center. To get the most out of your investment, remember what your mother always said about sitting too close to the TV-that it's no good for your eyes. For the optimal viewing experience, you need to maintain the right distance between your viewing area and your television screen. The right distance depends on the size of your TV: For 32 to 37-inch TVs, you should sit back 6 to 10 feet from the screen itself. For 42 to 46-inch TVs, you'll need 10 to 14 feet between you and the screen. 50-inch plasma displays look best when viewed from 12 to 16 feet away. You'll need at least 15 feet of space between you and a plasma scree that's larger than 60 inches. In determining the appropriate size TV for you, you should also consider the space required to install the unit itself. When recessing a plasma display unit, allow at least 3 inches of open space at the top of the unit and adequate ventilation space-at least 2 inches-behind it as well. Remember, too, that most plasma displays do not have built-in speakers, so you'll need to allow space enough to attach speakers (if you're not using a separate surround-sound setup) on each side of the TV. These speakers usually measure between 3 and 6 inches apiece. Know your audio options. Some manufacturers incorporate speakers into the frame structure of plasma televisions. Other manufacturers offer optional speakers that can be attached to the side of the display unit. Of course, you might also choose to use your own bookshelf or satellite speakers, in which case they'll need to be hooked up to an external amplifier/receiver component. Decide if you really want an HDTV and whether it's worth paying extra to have one. What?! Plasma TVs aren't all hi-def? The answer depends on what you consider "hi-def." All plasma screens are considered HDTV compatible or HDTV ready insofar as they will display high definition signals. High-definition televisions (HDTVs) are always more expensive than enhanced-definition sets (EDTVs). Whether a high-resolution monitor actually offers a better picture than an EDTV depends-on the quality of the signal input and on the manufacturer make. It also depends on what you're using the monitor for. If you're watching regular cable or DVDs, for example, EDTVs may produce a better picture simply because they more readily display lower-end video signals. If, on the other hand, you're one of the 55+ million households sitting astride cable systems that can carry HDTV, you might opt for the slightly better (10-15%) picture you could get from a higher resolution unit displaying HDTV broadcasts. Aside from the minor increase in quality one might expect when watching hi-def broadcasts on an HDTV, the real reason (some) people pay more for a high-definition plasma display is because higher resolution allows for markedly better displays of XGA signals from your computer. This is especially true of static images and numerals like those you would find on an Excel spreadsheet. So, if you intend for your plasma display to do double duty as a TV and as a monitor, you might spend a bit extra for a bit better resolution. Tip: To learn more about the availability of HDTV broadcasts in your area, or for a lineup of programs shown in hi-def, consult the Consumer Electronic Association's website <http://www.ce.org/publications/books_references/dtv_guide/default.asp> . Determine how you're going to install your plasma TV. Plasma technology affords consumers new options when it comes to the physical placement of their TV displays. Gone are the days when you had to configure a room around the television set. Now, you can incorporate the TV into almost any decor, if you give a little thought to the matter beforehand. There are half a dozen ways to install your new plasma TV, which virtually ensures that you'll find the right way to fit one in your home: Flat Wall Mounts allow you to maximize the space-saving benefits of plasma technology. This option is generally the least expensive, and it adds just under two inches to the monitor's total depth.  Tilt Wall Mounts enable you to place your TV above eye level, keeping it out of the way though readily viewable from anywhere in the room. This mounting option is typically used to install plasma displays above fireplaces and in bedrooms. The tilt wall mount adds from 4 to 6 inches to the depth of the mounted display. Table Stands are another popular way to display plasma units. Realize, though, that these units are not one-size-fits-all appliances. Each plasma display has its own custom-fitted table stand. Sometimes one is included with the monitor itself; other times, you have to purchase the stand separately.  Plasma TV Carts are typically used for business applications, but the benefits of a mobile display unit are in no way limited to the boardroom.  Articulating Wall Mounts make use of swivel arms to render the plasma unit flush with the wall-and out of the way-when not in use. Pulled out, this mounting device allows you to turn the display 120° to either side and as much as 10° up or down.  Ceiling Mounts enable you to mount your TV where you want it-in the event that a wall isn't handy. This option is generally coupled with a tilt mount, so that the display can be adjusted downward for easier viewing.  Lengths of ceiling mount poles vary according to customer needs, though the standard lengths are from 24 to 43 inches. ArtScren with the touch of a button, ArtScreen transforms your plasma television into a breathtaking work of art that enhances any room decor. Inside an elegant hardwood fram, an ultra-quiet motor raises the artwork to fully reveal the viewing screen. When turned off, your tv disappears as the ArtScreen is lowered into the picture frame.