Of course, the picture — especially the big-screen picture — provided by HDTV content shown on HDTV-capable displays is the number-one, numero-uno attraction. But — and we think this is a big but — high-quality audio reproduction comes in a close second when it comes to making HDTV more of a “you’re-there” experience. In other words, good audio (particularly, good surround-sound audio) lets you become more immersed in the HDTV experience — the audio helps make your HDTV viewing seem more like that proverbial window on the world. In this article, we give you good, quick info on the confusing specifications and terms that you’ll deal with when trying to understand the capabilities of an audio system. Some audio manufacturers fling bovine byproducts when they describe (dare we say overstate?) their audio capabilities, so you need some knowledge about what’s actually what in your audio systems. We also help you dig through the maze of surround-sound standards, to understand which speakers perform what function. We also cover the built-in audio systems found on most HDTVs. Grasping Audio Basics Before we get into any specifics about particular systems or audio components, indulge us by reading a few paragraphs about audio specifications. Yes, we know, reading the specs themselves is bad enough — now we want you to read about reading the specs? Yikes! Trust us, though; we have a method underlying our madness. Audio specs are some of the most misused numbers in the world. There isn’t really any enforced standardization in how manufacturers measure and report the numbers behind their audio — we’re talking mainly about audio power specs (watts). For example, two manufacturers may both claim that their systems put out 50 watts per channel (a decent amount). Neither manufacturer is actually lying when it states this specification — but one system may be much more powerful than the other. How is this possible? Well, the simple answer is that there are different ways of measuring the same thing (watts, in this case). Brand X’s watts may not equal Brand Y’s. Here’s an explanation:

-  Watts: The most basic measurement of an audio system — the number that gives you some idea of how loud the system is — is the power rating in watts. All else being equal, a system with a higher wattage rating should be able to play more loudly. Wattage is measured in watts per channel (or speaker). Keep in mind that it takes a large increase in watts to make a truly noticeable difference in volume. To make a system play twice as loud, you have to increase the wattage by approximately four or more times.

-  THD: Audio-system wattage is measured at a certain level of distortion (noise introduced by the audio amplifier system) called THD (total harmonic distortion). As audio systems are pushed closer to their limits (in terms of volume), they tend to produce greater amounts of distortion. Manufacturers can make a system seem more powerful “on paper” by measuring watts at a higher THD. Look for receivers that meet your wattage requirement when measured at low THDs, like .02 percent, rather than higher ones like 0.2 percent or even 1.0 percent.

-  Full-bandwidth power ratings: Another gray area in power ratings is the frequency range at which watts are measured. The human ear can hear audio signals between 20 and 20,000 kHz. It’s best if the system’s power is measured across this entire range. Some manufacturers provide wattage ratings at only one frequency (such as 1000 kHz), which can create an artificially high power rating. Try to find specifications that cover the full 20-to-20,000-kHz range to make true comparisons.

-  Ohms: The number of watts a system can produce is also affected by the impedance (or resistance) of the speaker being driven. Manufacturers generally measure impedance at 8 Ohms, but sometimes you’ll see wattage measured at lower impedances, such as 4 or 2 Ohms. It’s good that a receiver can drive speakers with such low impedances (not all can), but the wattage measured at 4 Ohms is higher, so it shouldn’t be compared directly to wattage measured at 8 Ohms.

-  Power handling: This rating (also measured in watts) relates to the speakers in an audio system, not the amplifiers. This is simply a measure of how many watts the speakers can take before they start to shred themselves into confetti. Power handling is not — we repeat, not — in any way a measure of how loud the system is. The main speaker measurement regarding loudness is the sensitivity of the speakers — a measure of how much volume the speakers put out with a certain wattage of input from the amplifier. The bottom line here is to make sure that you’re comparing apples to apples as you look at audio systems — either built into an HDTV, or in a separate home theater receiver system. To go back to our earlier example, two manufacturers may have 50-watt systems, but one may be measured at a limited bandwidth, at a high THD, and on a lower-Ohm impedance — and may be significantly less powerful than the other. Surround-Sound Mania The profusion of surround-sound standards is a confusing area in the audio arena. Surround sound is multichannel audio designed to produce spatial audio cues — sounds from all around you, in other words — relating to action on the HDTV’s screen. It’s usually described by the number of channels (or speakers) that a particular system uses to envelop you in sound: -  5.1- audio actually has six channels:

• A center-channel speaker (located directly above/below your HDTV) that reproduces dialogue on your screen.

• Two front (or main-channel) speakers, which reproduce most of the musical soundtrack, plus left and right spatial cues (like someone walking into the room from one side or the other).

• Two surround speakers, located on the rear side walls of the room, that produce spatial cues behind you, and also provide diffuse (not easily locatable) sounds to help create an audio atmosphere.

• An LFE (or low-frequency effects) channel that uses your system’s subwoofer (if you have one) to reproduce the very deep bass notes and sounds (like cannons exploding). The LFE channel, because it contains only a small portion of the full spectrum of audio frequencies humans can hear, is the “.1” of 5.1 (or any x.1 system). -  6.1-channel systems add one extra speaker — a rear surround that is usually located on the back wall of your HDTV viewing room, and that provides an extra level of surround-sound detail. -  7.1-channel systems that add two extra speakers, mounted on the back wall of the room. -  It can be encoded in a DVD or HDTV program discretely (each individual channel is recorded on its own channel within the audio soundtrack). This is the best way to accurately produce surround sound — when the director wants you to hear that spooky footstep right there, discrete surround sound gives you the best chance of hearing it there! -  It can be matrixed in along with other audio channels. Typically, matrixed surround-sound signals are mixed into normal twochannel stereo soundtracks. If you’re listening in stereo, you don’t even hear the surround-sound cues, but if you’ve got a surround-sound system, these “hidden” tracks are extracted from the stereo soundtrack.

-  Sometimes there is no surround sound (discrete or matrixed) for an HDTV program. Perhaps the movie was filmed in 1942, when there wasn’t even stereo! Well, surround-sound hardware can often create its own best guesstimate of surround sound, using a regular two-channel stereo input. If you’ve got a piece of physical media (such as a DVD), you can usually figure out which surround-sound format (or system) is being used by looking for labels (we’ll discuss the different formats in the following section). If you’re watching a broadcast (HDTV or standard-definition), you might see a label or description on an onscreen program guide (or in the paper or TV Guide). Luckily your surround-sound decoder — the device that “reads” the encoded surround-sound signals and turns them into sounds you can hear — usually detects surround-sound formats automatically. Introducing the formats Two companies dominate the surround-sound system market: Dolby Labs (www.dolby.com) and DTS (www.dts.com). Dolby is the market leader, but both are common on DVDs and other source material. These are the most common surround formats:

-  Dolby Digital/AC-3: The most common surround-sound format, Dolby Digital (also called AC-3) is part of the HDTV standard itself! Dolby Digital is a 5.1-channel, discrete surround-sound format, and in addition to HDTV programming, it can be found on most DVDs, and some digital cable and satellite TV programming. Dolby Digital doesn’t have to be 5.1 channels. It’s possible to use Dolby Digital for two-channel stereo or even mono (one-channel) soundtracks — which is often the case for older material filmed/recorded before the advent of surround sound.

-  Dolby Digital EX: As Dolby’s 6.1-channel solution (with the extra “rear-surround” channel added in), Dolby Digital EX provides 5.1 channels of discrete surround sound, but then uses a matrixed system for the rear surround.

-  Dolby Pro Logic II/IIx: Pro Logic II (a newer version named Pro Logic IIx is starting to appear on some audio/video gear) is Dolby’s system for decoding the matrixed surround sound found on some older TV sources — like VHS VCR tapes and some stereo NTSC TV broadcasts. Pro Logic II/IIx can also create relatively realistic-sounding surround sound from true two-channel sources like CDs or stereo TV broadcasts.

-  DTS: DTS is DTS’s equivalent to Dolby Digital — a 5.1-channel surround-sound format. You mainly find DTS on DVDs.

-  DTS-ES: DTS-ES is DTS’s equivalent to Dolby Digital EX; a 6.1-channel system. Found on DVDs, DTS-ES differs from Dolby Digital EX in that at least some DTS-ES soundtracks use a discrete rear-surround channel. Not all do, however — look for the DTS-ES Discrete logo on the DVD case, otherwise assume you’ve got a matrixed DTS-ES soundtrack.

-  DTS NEO:6: Not content to have equivalents to only Dolby Digital and Dolby Digital EX, DTS also has a system equivalent to Dolby Pro Logic II — DTS NEO. DTS NEO:6 takes twochannel audio input and magically creates multichannel 5.1 (or even 6.1 or 7.1) surround-sound soundtracks.

-  Proprietary encoders: Some HDTVs (and other surroundsound gear) have a surround-sound system from someone other than Dolby or DTS — these systems typically provide functionality similar to Pro Logic II or NEO:6, creating multichannel audio output from two-channel input. So why should you care? Well, you have two issues here: -  Be sure your system can decode the right audio formats. -  Buy the versions of audio that are most compatible with your system (or else know what you aren’t getting when you buy). In an ideal world, your audio-playback capability would support all these formats, but you want at least Dolby Digital. Most systems support both Dolby Digital and DTS. As far as the 6.1 or 7.1-channel systems go, that’s a matter of personal taste — there’s very little content out there for them, so they aren’t requirements. You can tell what encoding was used to create the audio by looking on the back of the DVD or CD.

Dealing with Built-in Audio

Most — but not all! — HDTVs have a built-in audio system. TV audio systems have never been known for their audio fidelity, but you’d be amazed at how good some of these built-in audio speakers sound. Even if you have a fancy home-theater audio system, you might find that the built-in audio system on your TV is good enough for casual viewing — such as watching the evening news, or listening in to The Today Show while cooking breakfast in the kitchen. In fact, there are times like this when it’s probably preferable to just fire up the HDTV and use its built-in speakers, rather than warming up the mondo complicated home-theater system. When using the TV with a surround-sound system on, the TV’s speakers usually assume the role of a center front speaker. Here’s what we think you should look for when you evaluate the built-in audio in an HDTV system:

-  Amp power: While amplifier power ratings for TVs are sometimes all but useless (see the following tips), you should look for a system that puts out 10 to 20 watts per channel, if you’re going to rely only on the TV’s audio system. Check out the THD (see the preceding section, “Grasping Audio Basics” if you aren’t familiar with THD) and other power rating factors when you examine this number. TV wattage ratings are often measured at significantly higher THD levels than “real” audio equipment is. So that “50-watt” TV system may be equivalent to a 10-watt home-theater receiver, powerwise. Some manufacturers claim “x” watts, but they aren’t talking about individual channels, but the sum total of all amplifier totals. You certainly can’t compare this number to the wattsper- channel rating of an external audio system.

-  Number of speakers: Most HDTVs include two speakers — left and right, in other words. A few have some additional speakers that you can place throughout the room — but this feature is increasingly rare, particularly in light of the low prices of hometheater systems these days.

-  External speaker attachments: Some HDTVs don’t have extra speakers, but have amplifiers that can power external speakers. In this case, you attach your own speakers to the back of your TV with some standard speaker cables. (Another rare option.)

-  Built-in surround-sound decoder: True HDTVs — those with built-in HDTV tuners — include a surround-sound decoder that can decode the Dolby Digital signal used by HDTV broadcasts. Most HDTVs only have two speakers, so they won’t create surround sound from an HDTV broadcast. The decoder is just there so the HDTV can turn the surround sound into two-channel audio, or feed surround channels to an external system.

-  Special two-channel surround modes: Many HDTVs include special audio circuits that can help create the illusion of surround sound from the two speakers built into the TV. (See the sidebar titled “Creating surround sound from thin air!”)

-  Connectivity to home-theater receivers: If (when, in our opinions) you decide to move beyond the two speakers built into your HDTV, you’ll want to connect your TV to a home theater receiver. If you have an HDTV with a built-in HDTV tuner, it needs a digital audio output to connect to your receiver. (Article 3 covers digital audio outputs.) This connection is almost standard equipment for any true HDTV, but you should make sure. Look for either Toslink (optical) output or coaxial digital output.

Creating surround sound from thin air!

You need at least 5 (.1!) speakers for real surround sound in a viewing room, but your brain can think you’re surrounded by speakers when you aren’t. For example, the folks at Dolby Labs have a couple of systems (which you may find in some HDTVs’ audio systems) that make two speakers sound like 5.1 or more! These systems (like Dolby Headphone, which reproduces surround sound for headphones, or Dolby Virtual Speaker, which does the same with two conventional speakers) use computer horsepower to modify the sound going to your two speakers (or headphone transducers) by adding echoes and delays. These echoes and delays are designed to reach your listening position so your brain is fooled into thinking that there are more than two speakers. Are these systems any good? They aren’t bad. Dolby Virtual Speaker and SRS Labs’ TruSurround can do a good job of fooling you. If you aren’t installing a real surroundsound system, look for an HDTV with a system like these. We don’t think you can substitute these “virtual” surround-sound systems for even a small, inexpensive “real” surround-sound system (such as a $200 “Home Theater in a Box” system). But if you don’t have the room or budget for 5.1 speakers, give virtual surround sound a whirl and see what you think.

Thin Is In Flat-panel TV technology — super-thin HDTVs that you can hang on the wall like a painting — have really taken a prime place in the popular zeitgeist. A big-screen, flat-panel plasma or LCD TV has become the status symbol of the ’00s — not just in the living room, but in hotel lobbies, retail stores, and even in the back of cars. There’s a good reason for this mania — flat panels provide a large viewing area with almost no intrusion into your HDTV viewing room. If that was all they did, they’d be pretty cool — but they can offer a very high-quality HDTV picture as well. In this article we talk about flat panels, and specifically about plasma HDTVs and LCD flat-panel HDTVs. We also discuss the pros and cons of each type, and compare them to other more traditional HDTVs. Many flat-panel displays ship as monitors only — with neither an HDTV nor an NTSC tuner included as part of the display. Remember that you need some sort of external HDTV and NTSC tuner (or a cable set-top box or satellite receiver) to view TV on these flat-panel displays. Loving Your LCD We are willing to bet that you’re already familiar with the LCD display. If you have a flat-panel display for your PC, a laptop PC, a PDA, a cell phone, a GameBoy — or just about any digital device with a display, you have an LCD. LCDs have been around for decades, mainly in lower-resolution formats and smaller sizes (such as phone screens), but they are getting larger all the time — and growing sharper in resolution. Even as they get bigger, however, LCDs tend to be the smallest HDTVs available on the market (so they may not be big enough for a true home-theater environment). The process of “growing” LCD crystals is a manufacturing challenge, and bigger LCDs are harder to make because they have lower yields (or percentage of LCD crystals that can be used for HDTVs). Because of this, most LCD HDTVs on the market are smaller than 30 or 32 inches — smaller, in other words, than projectors or plasmas (discussed in the second half of this article), and smaller than many tube-based CRT HDTVs. There are a few large-screen LCD HDTVs on the market these days — such as Samsung’s 40-inch model — and we’ve seen announcements (but not yet actual products) of 50-inch and larger LCD HDTVs. Typically, however, LCD gives way to plasma once you hit the 40-inch mark, for thin TV displays. Advances in LCD manufacturing, as well as new technologies, such as O-LED (Organic LED) and SED (Surface-conduction Electronemitter Displays), promise LCD-like displays in ever-bigger sizes in the future. In the long run, LCD displays will be huge! Not only will LCD HDTVs grow to huge dimensions, they’ll also be huge sellers. A few reasons why include the following: We’re not including the “super-skinny-hang-it-on-the-wall” attribute here, because we think that’s obvious. We can’t resist mentioning it again anyway, just because it’s so cool.

-  Excellent color: LCDs can display millions of colors, and do so accurately (meaning the color coming off the screen is faithful to the color in your broadcast or recording). Not all flat-panel TVs (or HDTVs in general) can duplicate this color accuracy.

-  PC-monitor-capable: Many LCD HDTVs can also be used as big (huge!) PC monitors. This trick is especially cool if you have one of those neat Media Center PCs we discuss in Article 16.

-  No burn-in: HDTVs that rely upon phosphors, such as CRTs and plasmas, can, under certain circumstances, experience burn-in, where ghost images are permanently burned into the screen. LCDs are immune from this phenomenon — so feel free to play video games, watch the CNBC stock ticker, and so on with no fear.

-  Inherently progressive: Unlike tube (CRT) TVs, LCDs don’t rely on a scanning “gun” and interlaced scanning (see Article 21). Instead, LCDs use millions of tiny transistors that can be individually controlled by the “brains” inside the display. This means that LCDs can easily handle progressive-scan sources, such as progressive-scan DVD and HDTV. Besides the size limitation we discuss earlier in this section, you might want to consider a few other issues before you choose an LCD HDTV:

-  Expensive for their size: LCD HDTVs are great, but they’re not cheap. Of course, all flat-panel TVs are relatively pricey, but LCD HDTVs typically cost more, per inch, than do plasmas. In the summer of 2004, you can expect to pay about $1,800 for an HDTV-ready, 22-inch LCD display. By comparison, an HDTV-ready, 32-inch direct-view set can be found for about half of that amount!

-  Poor reproduction of blacks: Black images are among the hardest for most TVs to reproduce (CRT TVs are best at this). LCD TVs tend to produce grays, not blacks — LCD HDTVs lose out, in this regard, to both CRT and plasma TVs.

-  Limited viewing angle: LCDs typically have a poor viewing angle — the angle you can sit away from perpendicular and still see a clear image on-screen. Manufacturers have been working diligently to improve this characteristic (with some success). Check the specs before you buy — most LCD HDTVs will have viewing angles listed in their specifications. There are not only horizontal (left to right), but also vertical (top to bottom) viewing angles. If you’re hanging an LCD HDTV on the wall, the vertical viewing angle may be more important to you than the horizontal — most people only pay attention to the horizontal viewing angle.

-  Slow pixel response time: Another area that LCD HDTV makers are working overtime to improve is the pixel response time of their TVs. Basically, the individual pixels within an LCD HDTV take a slight amount of time to change color and intensity. For really fast-moving video content (particularly in a 720p picture, where every pixel can change as many as 60 times per second), an LCD TV can end up with some artifacts (visible flaws) where the picture from a previous frame is still slightly visible onscreen as the new one is being drawn. Typically, this isn’t a huge and noticeable deal, but it’s not beyond the realm of possibility that you might notice it.

-  Limited brightness: The LCD is a transmissive system — light is shined through the liquid crystals — some of that light gets absorbed or reflected back away from the viewer. This means that LCD displays are not as bright as CRT, plasma and even some projection TVs (DLP, for example) — this could be a factor in a brightly lit room. Everyone’s Crazy About Plasma The really hot spot in the HDTV technology market is the plasma TV. Plasma TVs combine a thin, compact chassis with a truly large (even huge) screen size, and then add beautiful high-definition pictures to the mix. For many potential HDTV buyers, plasmas really fit the bill. A plasma screen contains literally millions of gas-filled cells (each one acting as a single image pixel) trapped between two pieces of glass. An electrical grid zaps these cells and causes the gases to ionize (and ionized gas is plasma — hence the name). The ionized gases, in turn, cause a layer of phosphor on the viewer’s side layer of glass to light up (just as the electron gun in a CRT causes the phosphor to light up on the front of the tube). Despite their compact dimensions (in the “depth” direction at least — many plasmas are only about 4 inches deep), plasma HDTVs are available in 42-, 50-, and even 60-plus-inch sizes. Imagine a 4- or 5-inch-deep HDTV that spans 5 feet diagonally, and you can see the instant appeal of plasma. Other benefits of plasma displays include these:

-  Excellent brightness: Plasma HDTVs are second only to CRT direct-view TVs (discussed in Article 24) in terms of picture brightness — plasmas don’t rely on a light bulb shining through or reflecting off of something (as an LCD or DLP system does). In some ways, plasma brightness is even better than CRT’s because the picture is uncannily evenly bright across the entire screen. In a CRT, on the other hand, there always is some slight (or not so slight) difference in brightness as the electron beam reaches different parts of the screen.

-  High resolution: HDTV plasma TVs can often reach higher horizontal resolutions that CRT-based direct-view sets just can’t match. The finest plasma TVs have such high resolutions (and such smooth images) that they look like nothing more than beautiful film images. Just because it’s plasma and it costs $3,000 or more doesn’t make it an HDTV. We don’t know of any sub-$3,500 plasma that isn’t an EDTV rather than an HDTV. This will change eventually, but for now, “cheaper” plasmas will be EDTVs.

-  Progressive by nature: Like LCD displays, plasma systems don’t use a scanning electron beam to create a picture. Instead, all the pixels on the screen are lit up simultaneously. Progressive HDTV sources (such as 720p) and non-HDTV sources (such as progressive-scan DVD players) are displayed to full advantage on a plasma HDTV.

-  A wide viewing angle: Unlike LCDs (which often have problems in this regard), plasma displays have a good picture even when you’re sitting “off axis” (not perpendicular to the screen surface). This is a huge benefit for smaller rooms, where viewers may sit relatively far off to the sides of the screen, at wider angles. Plasma’s not perfect, of course:

-  Susceptible to burn-in: Any system that uses a phosphor screen to display video can fall victim to the phosphor burn-in mentioned earlier in this article. If the Xbox is a primary HDTV source in your home, consider something besides a plasma — maybe an LCD HDTV or a rear-projection microdisplay HDTV. You can minimize burn-in on any display by calibrating the set properly and reducing the brightness from its (usually toohigh) factory setting.

-  Shorter lifespan: Another phenomenon of any phosphor-based display system is that eventually the phosphors “wear out” or lose their brightness. This is a subtle and slow process, but it inevitably happens. If you’ve saved up to buy an HDTV to last you a lifetime, well, don’t get a plasma unless your personal actuary tells you that you’re close to the end of your rope. Before you buy, check the manufacturer’s specifications on hours to half brightness (the point at which the display is only half as bright as it was when new). For example, if this specification is 20,000 hours, and you watch the set for 6 hours a day, it will be effectively worn out in about 9 years. If you have kids, keep in mind that 6 hours a day is (comparatively) not a lot of time for the TV to be on every day.

-  Less-than-perfect color reproduction: Although plasma displays are capable of producing a breathtaking array of colors, all the sets built to date have had an unfortunate tendency to make red colors look more orange than true red. If you’re a huge fan of slasher horror flicks, this might take away some of your fun!

-  Poor reproduction of black: Although plasma displays are a near equal to CRT sets in terms of absolute brightness, they fall short in the realm of reproducing black images. Most plasmas do slightly better job than LCD TVs at black reproduction, they fall short of CRTs and some projection systems (such as DLP). Keep in mind that every type of HDTV has its pros and cons. We’re certainly not trying to talk you out of going the plasma route (if your budget can handle it), just making sure that you’re informed. We doubt that you’ll find anything to dislike about the picture and performance of the best HDTV plasma sets — with the possible exception of the price tag!

Taking a plasma uphill Plasma TVs rely upon a thin layer of gas (which gets ionized and turns — eventually — into the picture you see). If you think back to your chemistry classes in high school and college, you may start remembering . . . well, let’s not go there. You may also, however, recall concepts like the ideal gas law (PV=nRT), which basically says that (all else being equal) the volume of a gas is inversely related to its pressure. Which is a nice way of saying that if the atmospheric pressure goes down (as it does at high elevations), a gas expands. As some folks living in high-altitude cites have discovered, this expanding gas can cause the glass screen in a plasma to “bow” outward, and potentially vibrate and make an annoying noise. If you live some place high (say a mile or higher), check with the manufacturer’s specs before buying a plasma set. Many manufacturers have begun to make specific design changes in reaction to this situation, and have begun selling plasmas that won’t get altitude sickness.