How to Buy an Integrated Home Theater Audio System
Introduction
Photograph by Marc Simon
HTiB systems range from the very basic, designed to plug into your TV set and be ready to go, to the very sophisticated, with features like built-in DVD players and performance rivaling that of elaborate component rigs. more
Of the many specifications used to describe audio systems, you may be surprised at the few characteristics that are really important. We help you demystify those cryptic names and numbers. more
Home Theater Audio Shopping Tips
Before you head to the showroom, check out these simple keys to choosing the home theater audio system that's right for you. more
The Big Picture
Photograph by Marc Simon
Prices range from a few hundred dollars for extremely low-end systems to several thousand for the most ambitious. Systems with good overall performance, sound quality, and bass typically start at around $500.
For more information on the other components, read "How to Buy a Home Theater System."
Speakers
Systems typically include five to seven relatively small satellite speakers plus a considerably larger bass module, or subwoofer, which reproduces most of the low frequencies.
The satellites break down into three functional categories: center, front left and right, and surround. The center speaker goes directly above or below the TV screen (usually right on top of the set). Front left and right satellites are placed at the sides of the screen, at equal distances from it. Although the two main surround speakers are often called "rear speakers," they really should be positioned just slightly behind and along the sides of the seating area whenever practical. (An extremely bare-bones system might include just a single surround speaker for placement at the back of the room, but this is rare nowadays.) Many systems use identical satellites for all locations, while others may have somewhat different speakers for the center or the surrounds. The center may be designed specifically for horizontal placement, for example. What's important is that their tonal character be the same.
The subwoofer can usually be placed just about anywhere that's convenient, though its sound will vary somewhat depending on its placement and the acoustical characteristics of the room. Design details, such as whether the subwoofer cabinet is sealed or ported (which means there is a hole or vent in the box), are seldom a significant shopping consideration. Be aware, however, that it is harder to get strong deep bass from a small box than from a large one. That doesn't mean you have to buy a huge subwoofer to get good sound, but don't expect miracles from a tiny one.
That's it for a standard 5.1-channel setup (five plus the bass-only ".1" channel handled by the subwoofer). Some systems provide one or two additional back-surround speakers for 6.1- or 7.1-channel operation. These additional back-surround speakers should be positioned behind the seating area.
Amplifiers
An amplifier strengthens audio signals enough to drive the loudspeakers. A system's amplifiers may be built into the individual speakers, into the subwoofer (in which case all the satellites connect to the subwoofer), or into the control center that contains the surround decoder. When a manufacturer creates a system by packaging a regular audio/video receiver with a set of speakers, the amplifiers for the satellites will normally be in the receiver and the amplifier for the subwoofer in the subwoofer itself. Any of these configurations can work very well, and there is no reason to prefer one over the other in terms of performance.
Control Center
The system hub is a control center that provides surround-sound decoding, volume control, and other basic functions. (Often it will be a standard audio/video receiver.) An extremely simple unit might provide just one set of audio inputs, for connection to the audio outputs on a TV set. Most, however, provide multiple inputs and the ability to switch between them using a remote control.
In a system with Dolby Digital decoding capability, at least one input will be digital. Dolby Digital is the standard audio format for DVD and HDTV, so this capability is highly desirable. At minimum, you should expect Dolby Pro Logic decoding, which will work with just about any surround-encoded soundtrack you encounter. (Since devices such as DVD players, which are designed for Dolby Digital, provide Pro Logic-compatible analog outputs as well, you will not be left out in the cold, although the quality of the surround will be somewhat lower.)
Many control centers provide video as well as audio switching. That allows you, for example, to connect the audio and video outputs from a DVD player and a VCR to the control center, and connect its audio and video outputs to one set of inputs on the TV, with all switching done through the control center. Some also have built-in DVD players for watching DVDs and listening to CDs.
Choosing a System
Pay attention to the speakers and a handful of details, and it's hard to go wrong.
The Specs Explained
Photograph by Marc Simon
Important: Surround Decoding
The surround-sound formats supported by the system will affect the realism and intensity of the experience.
Dolby Pro Logic: base-level surround decoding that will work with essentially any source. Generates front left and right, center, and surround outputs (with the mono surround output normally reproduced through two speakers). Works well only with Dolby Surround-encoded soundtracks. This or Dolby Pro Logic II is an essential feature.
Dolby Pro Logic II: an advanced version of Dolby Pro Logic that is starting to come into wide use. It provides superior surround decoding with stereo surround output. Also works very well for generating five-channel surround from two-channel stereo music recordings, such as CDs. Highly desirable. If you could have only one surround decoding option, this would be the one to choose.
Dolby Pro Logic IIx: enhanced version of DPL II that can deliver up to 7.1-channel output. Nice if you can put one or two back-surround speakers in the room in addition to the standard left and right surrounds, but useless otherwise.
Dolby Digital: Dolby Digital decoding is the best choice for multichannel Dolby Digital soundtracks delivered in that format, as they are on DVD, HDTV, and some satellite transmissions. But it's useless for things like VHS releases or analog TV programs that can't carry Dolby Digital but can deliver Dolby Surround. For those you need Dolby Pro Logic or Pro Logic II, which are, in effect, universal sound decoders. And, if you have to choose just one, choose DPL II.
Dolby Digital EX: enhanced version of Dolby Digital that allows a back-surround channel in soundtracks in addition to the usual left and right surrounds. Nice to have if you can accommodate the extra speaker or two at the back, but useless otherwise. Works well with Dolby Digital EX and some regular Dolby Digital soundtracks.
DTS: an alternative surround encoding/decoding format that is functionally equivalent to Dolby Digital. It offers no advantage, however, and is not as widely used. Not really needed except for certain special DTS-encoded multichannel CDs.
Important: Frequency Response
Frequency response measures both the range of frequencies that can be reproduced, from lows to highs, and the evenness of their reproduction. For example, you might see something like this: 40 Hz to 20 KHz, +/-3 dB. That means low frequencies from 40 Hz (cycles per second) to high frequencies up to 20,000 Hz (the approximate upper limit of human hearing) are reproduced with no more than 3 decibels of deviation from perfect accuracy ("flat" response).
The part of all this that is worth paying attention to is the low-frequency limit. For most music and many movies outside the action and sci-fi genres, a lower bass limit of 50 Hz will do. Pushing the bass down to 40 Hz will ensure that you never feel seriously deprived. And if you get it down to 30 Hz or below, you can feel some pretty bone-rattling effects.
Important: Audio Inputs
The number and type of audio inputs available in the control center or audio/video receiver determines how many sources you can connect to it and what you can do with their outputs.
Line-level stereo: Your ordinary, everyday analog audio connection, normally consisting of two RCA jacks. Any audio or audio/video source will have compatible outputs. These are fine for stereo or Dolby Pro Logic reproduction.
Coaxial digital: One of two types of digital audio connections. This type uses an RCA jack; the cable should be 75-ohm coax (any cable labeled for video or digital audio). A digital audio connection--either coaxial or optical--is necessary for Dolby Digital (or DTS) decoding. The type doesn't matter; you just have to match input to output.
Optical (Toslink) digital: The other type of digital audio connection, which uses fiber-optic cable for signal transmission.
Somewhat Important: Speaker Configuration
Surround encoding and playback is defined according to a number system.
For example, Dolby Surround is a 4.0 system, with front left and right, center, and mono surround channels. Dolby Digital is a 5.1 system, with front left and right, center, left and right surround, and low-frequency effects channels. (The LFE is the ".1 " channel.)
Dolby Digital EX is a 6.1 system. The speaker systems used to reproduce these formats are usually 5.1, 6.1, or 7.1, with the latter two adding one or two back-surround speakers, respectively, in addition to the standard left and right surrounds. In this context, the ".1 " refers to a subwoofer (which will usually reproduce deep bass from the main channels in addition to the LFE). In some cases one surround channel may be routed through two surround speakers, as in a Dolby Pro Logic decoded Dolby Surround soundtrack in a 5.1 system or Dolby Digital EX in a 7.1 system.
5.1: This is pretty much the base format now, capable of excellent performance.
6.1: This system adds a third surround speaker directly behind the seating area, which is nice when the room can accommodate the extra speaker, but generally not practical when the seats are against the back wall.
7.1: Two back-surround speakers are positioned behind the seating area instead of just one. A 6.1-channel soundtrack usually sounds better with 7.1 playback than with 6.1, so it's not gilding the lily.
Somewhat Important: Video Inputs
These are only somewhat important because you usually don't have to route video signals through the audio control center. But video inputs can be a convenience.
Composite-video: This provides the lowest quality but broadest compatibility. Any device that has video outputs will include composite-video among them. The connection is made with a single 75-ohm coaxial cable between RCA jacks.
S-video: For better quality, most video sources except standard VCRs now have S-video outputs. This is connected with a special cable and multipin sockets.
Component-video: This high-quality spec is the minimum standard for connecting HDTV tuners and progressive-scan DVD players. It requires three 75-ohm coaxial cables of the same type used for composite video.
DVI: This digital RGB connection, the highest-quality option, is commonly used for HDTV tuners and occasionally for DVD players. It requires a special cable and multipin sockets. You're not likely to find this one on current integrated home-theater audio systems.
Minor: Amplifier Power
Surprised? A speaker's ability to reproduce sound loudly depends on both amplifier power and the sensitivity of the speakers, which is seldom specified for this type of system. Highly sensitive speakers don't need nearly as much power as less-sensitive ones to sound just as loud. For example, a speaker with 91-dB sensitivity will sound just as loud with a 50-watt amplifier as a speaker with 88-dB sensitivity will with a 100-watt amp. And because amplifier power is cheap these days, it's rare for any systems, other than very low-end ones, to be underpowered. The shortcomings tend to be elsewhere.
Home Theater Audio Shopping Tips
Photograph by Marc Simon
Listen: When it comes to evaluating sound, there's no substitute for your own ears. The quality of a system's speakers will make or break its performance, and you can't gauge that from specs or descriptions alone. Take your own discs so that you can listen to material you're familiar with. And even if you intend to use the system only for movies and TV, include some music CDs. They will make it a lot easier for you to spot problems with tonal balance.
Push the subwoofer: Calling Arnold! Here's where you will need a DVD, preferably a noisy thrill-fest. Find a scene with some heavy bass action and see how the system's subwoofer holds up when you really crank it. You want one that won't wimp out on this sort of material at the volume levels you like to hear.
Don't hesitate to go digital: Even if all you've got right now is a VCR and a 10-year-old TV, chances are you're going to wind up sooner or later (probably sooner) with a DVD player or HDTV that will really benefit from Dolby Digital decoding in the sound system. It's not a big premium anymore.
Look before you leap: Take a good, hard look at the room where you plan to use the system. What has to go where, what can go where, and how big can it be and still fit? There's no point in paying extra for a 7.1-channel system if you've got no place to put the two extra surround speakers, for example. If cabinets are involved, make measurements and carry them with you. A small pocket tape measure can be very handy.
Don't get caught up in numbers games: A thousand watts into crummy speakers is just really loud bad sound. And 20 surround modes is 17 too many if you're going to use only three of them. Stay focused on good sound and ease of use.
Get to know the remote: A poorly laid-out remote control is a pain forever. How easy is it to find critical buttons (volume, pause, mute, channel, and so on) in the dark? How comfortable is it in your hand?