Stick with Reputable Brands and Retailers
Be wary of deals that seem too good to be true — especially online. While megastores can offer a big selection and big discounts, specialty retailers may have dedicated home theater demo rooms and can offer much more personal service.
Consider Spending a Little More than You’d Planned
Like anything else, in home theater you get what you pay for, and spending more now will very likely yield a system that will make you much happier in the long run.
Take Your Time
Don’t let anyone rush you. Sure, you’ll probably want to buy something right now, but resist those impulses. There’s no way to make a good decision in just a few minutes.
Stereo or Surround?
If you’re going to use your system just for music listening over two speakers, you’ll want a stereo receiver. Besides accommodating two-channel sources such as CD and cassette, some stereo receivers even include a phono input for those who still enjoy listening to vinyl records. Some models also include video switching so you can connect your TV and a video component, such as a VCR or DVD player, and enjoy better stereo sound than the TV’s own speakers can provide.
Traditional stereo receivers are going the way of the turntable, however, as most people choose an audio/video receiver to serve as the hub of a home theater setup. A/V receivers not only play stereo sources but can also deliver surround sound from DVD players, satellite receivers, VCRs, and other multichannel or stereo sources. An A/V receiver offers at least five channels of amplification plus volume control, surround sound decoding, an AM/FM tuner, and connections and switching for a variety of components.
Inputs and Outputs
Make sure you have enough audio and video inputs for all of your source components. Figure out how many sources you’ll need to connect — and then allow for future additions to your system. Since you have to use the digital audio connections from your source components to get surround sound — except for DVD-Audio and Super Audio CD playback — make sure the receiver has enough digital audio inputs. (For DVD-Audio and SACD, you’ll usually need a receiver with a multichannel analog audio input.) And make sure your receiver has HDTV-compatible component-video inputs so you can use it to switch between high-def sources.
Check Out the Remote
You’re going to be spending a lot of time with your receiver’s remote control, so consider how easy it is to use. Most receiver remotes can also operate other components in your system, so be sure to ask the salesman about that. And make time while you’re in the store to navigate the onscreen menus and operate basic receiver functions from the remote. If the remote feels awkward or seems too difficult to learn, you might want to consider a different receiver.
Don’t Neglect the Boring Details
Make sure the receiver will fit into your equipment cabinet or rack. Sounds obvious, but...
And make sure you have all the types and lengths of cable you will need. Once you get your gear home and are ready to set it up, you’re not going to want to go back to the store to get more speaker wire or an extra interconnect cable.
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Understanding the Technology
A/V Receiver Basics
A digital surround receiver is the heart of your home theater. Besides delivering power to all your speakers (except the subwoofer), it lets you switch between your DVD player and other source components, sends the video signal to your TV, and does the surround sound processing that turns your family room into a theater.
Today’s receivers offer far more features and even better performance than those of just a few years ago. Things like processing for surround sound playback of stereo programs and switching for high-definition video sources are available even in inexpensive models.
All home theater receivers decode the Dolby Digital 5.1 soundtracks found on virtually all DVDs, and most also decode DTS and a variety of other surround sound formats. Most now also offer 6.1- and 7.1-channel decoding and amplification as well.
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Power
The Short Course
It’s important to know how much power you’ll need per channel, and it depends on several factors, including the size and acoustical characteristics of your room, how loud you like your music and movies, and how efficient your speakers are, as indicated by their sensitivity rating. (A 3-dB increase in sensitivity means that you need half as much power to produce a given sound level, while a 3-dB decrease in sensitivity means you need double the power to achieve that volume.) It takes less power to fill “live” rooms that have hard, reflective surfaces than “dead” ones that have lots of upholstered furniture and thick carpeting.
All things considered, you’ll probably need less power than you think: 40 or 50 watts per channel is plenty for most music listening, and unless you have a really big or really dead room or unusually inefficient speakers, 80 to 100 watts per channel will ensure action-movie climaxes don’t sound wimpy. Having more power on hand never hurts, but there’s no good reason to use a receiver with more than 100 watts per channel in a compact bedroom system, and very few people need more than that even in their main home theater systems.
In-Depth Guide to Power Specifications
On the surface, an amplifier or receiver power specification looks pretty straightforward — “100 watts per channel,” for example. Amplifiers are not light bulbs, however, and a complete power spec is quite a bit more detailed. The Federal Trade Commission (FTC) requires that a manufacturer’s primary power rating for a home audio amplifier (whether separate or built into a receiver) be its average continuous power into an 8-ohm impedance. It must also include the frequency range over which the rating is valid and the maximum distortion over that range at the specified output level. In other words, a typical power spec, in its full glory, might read something like this: “100 watts per channel from 20 Hz to 20 kHz into 8 ohms with less than 0.05% THD,” where THD means total harmonic distortion.
That spec packs in a lot of information. It tells you that each amplifier channel can deliver at least 100 watts at every frequency within the audio band, which probably means that the amp or receiver can deliver a bit more power at frequencies in the midrange, where most of the action is. It also tells you that the output waveform will be an almost perfect replica of the input — just larger. That’s the significance of the distortion figure, which indicates what proportion of the output consists of stuff that shouldn’t be there. With complex sounds, such as most music, the ear is surprisingly tolerant of distortion — several percent or more may go completely unnoticed. So if the maximum distortion is held to 0.1% or less, you can be sure that you’ll never hear it. (In normal use, any maximum distortion figure below about 1% is going to be pretty safe.)
Distortion is part of the power specification because when an amplifier begins to run out of steam, distortion starts rising. And when the amp is completely overloaded, it cuts off the peaks of waveforms — a condition known as “clipping” that produces a very ragged-sounding distortion. The distortion part of the power spec keeps the manufacturer honest. An amplifier or receiver might be able to put out more power at 10% distortion than at 0.5%, but the extra apparent oomph is just that — apparent. It’s too garbled to be useful.
Even within the realm of reason, there’s some maneuvering room. The same amplifier or receiver tagged with the typical power spec cited above might also be honestly rated at, say, 115 watts per channel from 40 Hz to 20 kHz into 8 ohms with less than 0.9% THD. The difference between the two specifications is inconsequential on all counts. Just recognize when comparing power ratings that this sort of leeway exists.
The last element of the standard power specification is the impedance of the load the amplifier’s output is connected to. Even before the FTC stepped in, the de facto standard for impedance had been 8 ohms for many years because most speakers have nominal (rated) impedances of 8 ohms or close to it.
That’s not the case for all speakers, however — some mainstream speakers have rated impedances as low as 4 ohms. Besides, the impedance of nearly all speakers varies with frequency, often substantially, which means that an impedance rating is really an approximation. An “8-ohm” speaker might have an impedance ranging between, say, 5 and 32 ohms over the audio frequency band. Depending on how an amplifier is designed, these changes in impedance could present significant challenges while playing music or movie soundtracks.
The reason is found in Ohm’s law, which states that for a given voltage in a circuit, the lower the impedance, the higher the current. Because power is voltage times current, an audio amplifier can usually deliver more watts as the load impedance is reduced — at least up to the point where it can’t pump out more current without shutting down or throttling back to protect its output transistors from overheating. An amp with inadequate output-current capability can choke on low-impedance speakers.
Most good amplifiers and receivers today, including many that come with cautions against using speakers with impedances rated less than 8 ohms, will handle 4-ohm speakers without terrible distress, and the best high-end amps hold up well down to 2 ohms or less. Still, if you’re using low-impedance speakers, it’s a good idea to make sure any amplifier or receiver you buy will be happy driving them. Look for a 4-ohm power rating in addition to the standard 8-ohm one. In particular, make sure that the rated power output into 4 ohms is at least as great as into 8 ohms — preferably, it should be at least 25% higher. If no 4-ohm spec is published, check with the manufacturer.
Finally, almost all amplifiers and receivers will deliver slightly more power in short bursts than they can continuously, which is great, since music often contains brief peaks (called “transients”) that are considerably louder than the average level. The dynamic-headroom specification is designed to account for this characteristic. It indicates, in decibels (dB), how far above its continuous rated power an amplifier can go for short intervals, with 1 or 2 dB being typical. Getting more than 3 dB of dynamic headroom from an amp usually requires either special circuitry or an artificially low continuous-power rating.
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Understanding Our Lab Data
How to use our lab tests for digital surround receivers.
Setup
Our step-by-step guide that will take your receiver from fresh-out-of-the-box to Control Central.
Perplexed by mysterious jacks on your A/V gear? Our comprehensive guide will help you hook it all up.
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