How to Buy an A/V Receiver
An A/V receiver combines three audio components in one box. Primarily, it performs the traditional roles of a preamplifier and power amplifier. The sound for any home theater begins as a relatively low-level audio signal coming off a source component such as a cable box or disc player. These days, it’s more likely to be a digital audio signal than an analog signal. That signal gets converted between digital and analog as needed, manipulated to affect your volume adjustment, and might perhaps have some bass and treble contouring (or more sophisticated equalization) applied before it’s sent to the power amplifier, whose only job is to pump it up to the power level necessary to drive your speakers to sufficient volume.
Today’s AVRs perform a third important function in the same chassis, and that is to decode and steer the multichannel digital soundtracks found on modern-day Blu-ray Discs, DVDs, broadcasts, and Internet-streamed programs. In the early days of surround sound, this might have been performed by a standalone processor, but now it’s seamlessly integrated with the preamp section of the receiver. The surround processors in modern AVRs also allow you to turn two-channel stereo content into some form of multichannel surround sound utilizing all your speakers.
The preamp section of your AVR further provides switching from one source component to another, so you can go from watching a Blu-ray to a TV show with the push of a button. Since the receiver must accept both the audio and video signal to achieve this routing, AVRs have evolved to where many also provide video processing that simplifies hookup of different types of source components to your HDTV and may improve image quality at the same time.
AVRs have additional features today that optimize the audio quality for your specific listening room and tailor the sound to your taste depending on the content. We’ll say more about these later.
Channels and Power
Although AVRs do add features as you move up in price, the key benefit of spending more money should be more powerful amplification. A great amplifier with power to spare will rise to the occasion on loud, complex passages without introducing audible distortion. Determining precise power requirements for your needs can be tricky, though. Not only does it depend on your room size and your speakers’ efficiency in converting power into sound, but you can’t count on manufacturers’ power ratings from one AVR to another for an accurate reading of a unit’s true capabilities. Two AVRs, both rated to attain 100 watts per channel RMS at low 0.1 percent distortion while driving a pair of 8-ohm-rated front stereo speakers, may not perform the same way when called on to play loudly with complex multichannel content. Some AVRs will run out of steam and clamp down on power output to all the channels or even shut down temporarily to avoid overheating and potential damage.
A telling sign is the all-channels-driven test bench measurement Home Theater includes with all AVR reviews. Although this torture test is far more demanding than any real-world situation an AVR is likely to encounter, power output that meets or comes reasonably close to the published two-channel specification with five or seven channels working all-out simultaneously is a likely indicator of a more robust power supply and the ability to drive your system to louder levels with less strain. Keep in mind, though, that the amp that achieves this isn’t always the biggest or heaviest. New circuit topologies are now cropping up—notably Class D switching amps—that can deliver their power to the speakers more efficiently than traditional hot-running Class AB or Class A amplifiers. However, this new generation of Class D AVRs seems to vary widely in sound quality. Read the reviews before you buy into the hype.
THX-certified AVRs, when mated with THX-certified speakers, will guarantee the ability to achieve a certain volume level in a room whose cubic volume is specified by the level of certification. Visit THX.com for more information.
How many channels and speakers do you need? Many experts agree that the basic 5.1-channel configuration is sufficient for an engaging home theater experience. This includes front-, left-, center-, and right-channel speakers; a pair of surround speakers placed ideally along the side walls (and slightly behind the prime seats); and a dedicated powered subwoofer (the .1). Until recently, there’s been little discrete 7.1-channel software to justify the use of adding back surrounds to fill out seven primary speakers. That’s changing now that we have Blu-ray Discs that carry high-resolution 7.1-channel soundtracks and more filmmakers embracing 7.1 for their initial mix. Still, extra speakers beyond 5.1 channels should be considered an enhancement and not a requirement, even though only the cheapest AVRs today provide fewer than seven internal amps. Those two extra channels can be used to drive back surrounds, but most AVRs can be set to allow them to drive a pair of Zone 2 speakers in another room.
Beyond seven channels are AVRs with nine or even 11 channels (through a combination of speaker and line-level amplifier outputs) that can make use of the front height and front width channels derived artificially from 5.1-channel soundtracks by some of today’s advanced surround modes (see below). Again, with no discrete soundtracks available to take full advantage of these extra speakers, the value of adding them remains debatable.
One of the things that adds to the intimidating complexity of operating an AVR are the many surround listening modes provided. Several of these perform similar functions, with technology provided by the competing entities Dolby, DTS, Audyssey, and even THX, which adds its own tweaked surround modes to its THX-certified receivers.
Bottom line: Although experimentation is encouraged, you are best advised to play back your content using whatever mode is native to the format encoded on the original soundtrack if you wish to enjoy the full effect of what its creator intended. Fortunately, every AVR comes with the modes needed to decode the soundtracks found on DVDs and Blu-ray Discs. This includes standard Dolby Digital and DTS embedded on DVDs and the high-resolution lossless formats Dolby TrueHD and DTS-HD Master Audio found now on most Blu-ray Discs. The latter formats are noticeably superior to the earlier lossy compression formats and are one of the best reasons to upgrade to a new AVR if you’re not yet taking advantage. Most TV broadcasts carry lossy Dolby Digital, and some streaming content from major services, such as Vudu and Netflix, are now using Dolby Digital Plus, which provides modest benefits in transmission efficiency or sound quality over traditional lossy Dolby Digital. Set your new AVR’s surround mode to its automatic setting, and if you’ve selected bitstream audio output for your Blu-ray player and other digital sources, the receiver should recognize what’s on the source material and set the surround mode accordingly.
The next suite of essential listening modes found in AVRs are for decoding matrix-surround encoded two-channel sources and converting two-channel stereo recordings or TV shows into quasi surround sound. The best known of these are probably Dolby Pro Logic IIx and DTS Neo:6. These vary in their effectiveness depending on the program material, but they’re generally available as part of the Dolby and DTS processing package included with the receiver.
Dolby Pro Logic IIz and Audyssey DSX are increasingly turning up now in mid-level to high-end receivers. These modes allow, sometimes with the requirement of some extra outboard amplification, the addition of extra front height and/or front width speakers that would mount above and to the outside of the main stereo pair. Again, the jury remains out on the value of using these modes for playing back the 5.1 and 7.1 soundtracks found on movies today.
You’ll also find that manufacturers offer their own proprietary modes for adding extra channels or converting stereo to surround. These vary in their effectiveness, and you’ll need to read the reviews or try them yourself to find which ones are of value to you. Incidentally, these are separate from the palette of bogus reverb modes that some AVRs still offer, those with names like Church and Stadium. You’re best off skipping these.
Compression and Volume Modes
When you need to turn the volume down to avoid disturbing neighbors or family during the loudest passages, dynamic compression and volume normalization help your ability to hear quiet dialogue without being blasted by the special effects and spare you from aggressively riding the volume control during TV shows and movies. Some AVRs still come with a Night mode for this, but they don’t typically achieve the performance of third-party offerings by Dolby, Audyssey, and THX. Audyssey Dynamic EQ and THX Loudness Plus (offered on THX-certified receivers) seek to maintain proper frequency balance and dialogue clarity as the volume gets lower, as does Dolby Volume. Dolby Volume, as well as Audyssey Dynamic Volume, can also help minimize swings in loudness as you transition between TV programs and commercials, or between source components with different output levels that you can’t adjust in the source or receiver.
Programming from TV broadcasts or DVDs must eventually be upscaled and/or deinterlaced before being displayed on a native 1080p HDTV. Most often this is done in the source or by the display, but better AVRs offer onboard video processors, often from respected brands like Marvell Qdeo or Anchor Bay, to perform these functions in the receiver, sometimes to better effect. Another key benefit to onboard video processing is the ability to cross-convert the analog composite and component video from legacy components like VCRs or game consoles for viewing through the AVR’s HDMI monitor output. This allows just a single HDMI cable connection from the receiver to the TV, greatly simplifying hookup. Only better AVRs have this feature, though, so if it’s important to you, do your research.
Auto Setup and Room Correction
Setting up a receiver properly involves making menu selections to tell the AVR how many and what type of speakers you have, what their relative locations are to the primary listening position, their bass capabilities, and what volume level each should be set at relative to the others so the listener experiences a coherent soundfield. You can do all this manually—or just run the microphone-enabled auto-setup routine that’s included with most AVRs nowadays. In addition, many receivers will take it a step further and apply equalization across a range of frequencies to smooth out the in-room response, a particularly helpful benefit when it’s applied to the low bass frequencies where most rooms have their worst problems.
Audyssey has the best-known solution for this with its MultEQ family, with different levels of resolution applied to products at different price points. (You can read more at audyssey.com/audio-technology/multeq.) AVR makers that don’t use Audyssey often have proprietary systems that range from god awful to quite impressive. Again, you’ll have to read the reviews to see whose systems work best. Either way, you’ll usually have the option to tweak the results or ignore them.
Last year, it was still a big deal to find a receiver that featured the latest high-speed version of HDMI (then called Version 1.4) that could pass a 3D signal from a 3D Blu-ray player or cable box to a 3D-capable TV, as well as offer new HDMI features like Audio Return Channel, which allows the audio content from smart TV streaming services to get back to the AVR via the same HDMI cable used to bring images to the TV. Now every AVR is 3D ready, and most offer a good number of HDMI inputs to accommodate modern digital sources. Legacy inputs for composite, S-video, and component video sources are becoming harder to find, however, so if you have older non-HDMI components, check carefully to make sure you have enough inputs of the right type and that the unit will indeed cross-convert these to the AVR’s HDMI output if required by your setup.
For 2012, the big push is iPod connectivity. More units are featuring the convenience of an Apple AirPlay Wi-Fi link or a Bluetooth connection between your network-connected AVR and mobile devices, allowing you to simply pick up your iPhone, iPad, or iPod touch and push your iTunes music library to the receiver. AVRs also offer Made for iPod USB connections, which allow direct connection of an iDevice through the standard Apple 30-pin cable; once connected, all the content on the iPod can be called up via the AVR’s remote and scrolled on the onscreen graphic interface or front-panel display.
Network and Internet Services
Network-connected AVRs that link to your home network with a wired Ethernet or wireless Wi-Fi connection are all the rage now—and surprisingly affordable. More often than not, they feature the ability to directly stream music via services like Pandora, Rhapsody, and Spotify, as well as some facility to capture Internet radio streams from distant lands and your local stations (often a more reliable option than an FM antenna). Also common now is compatibility with the DLNA standard, which lets you call up audio and video files from your network-attached computer or hard drive to play on your AVR and HDTV.
Remote Control Apps
The last significant trend this year is the growth of iDevice- and Android-based control apps that you can download and run on your handheld to turn it into a touchscreen remote for your receiver. All that’s required is a network connection to the AVR and a wireless Wi-Fi network for the app to talk to the receiver. Couldn’t have happened sooner. AVRs are notoriously difficult to operate thanks to their myriad capabilities and remote controls that are littered with tiny, poorly labeled buttons. The best touchscreen remote apps greatly simplify day-to-day operation of basic functions and can make these complex components a pleasure to use. They’re also a godsend when you’re running second-zone audio off the AVR, because the touchscreen usually allows selection and browsing of network sources, as well as volume adjustment, from inside the second zone. Major manufacturers who didn’t have an app last year have one now, and they are being regularly improved. If you’ve got an Apple iPhone, iPad, or iPod touch, or an Android phone or tablet, make sure you research what kind of app is available for the receiver you’re considering. You’ll be glad you did.