Receiver Guide

There is a jungle of surround sound options available with receivers these days. What do you need, and what will get in the way? PowersellerNYC’s audio teamwill help you find the perfect AV Receiver.

Frequently Asked Questions

DTS ("Digital Theater Systems")

Pepsi to Dolby's Coke, DTS is also a digital surround format that's most often encoded at 5.1-channels for program material. DTS too was born on Laserdisc first, and followed Dolby Digital to DVD, although as an optional codec it's been used on DVD quite sparingly. While DTS is also a "lossy" compression scheme, its claim to fame is operating at higher data rates, thus requiring less compression of the original signal.

While you can't really compare different codecs based on their data rates alone, DTS has developed a strong following over the years, and many enthusiasts do prefer it to Dolby Digital. But DVD and broadcast media have bandwidth and storage space limitations, and the data required for DTS' audio leaves less room for high quality video and, on DVDs, extra features. This has limited its use. It has been more prevalent so far on Blu-ray and HD DVD, which offer much higher data rates and far greater storage capacity.

Dolby EX, DTS-ES, DTS 96/24

Dolby Digital Surround EX

Surround EX adds a third surround channel to traditional 5.1-channel Dolby Digital. This rear surround channel can be decoded and played back using a single rear surround speaker, or two. The idea is that the basic surround channels are placed on the sidewalls, with the rear surround speaker(s) placed along the back wall. This ostensibly allows more distinct and convincing sonic pans from front to back in the soundstage.

There is very little program material officially encoded with this rear surround channel, but in theory if a soundtrack is mastered this way theatrically it would also carry over to the 5.1-channel soundtracks on DVD, broadcast HD, or next-gen HD media

DTS-ES

DTS-ES is DTS' answer to Dolby EX and works in essentially the same fashion as far as the speaker configuration is concerned, and comes in two flavors: DTS-ES Matrix and DTS-ES Discrete. The Matrix version of DTS-ES works much the same as Surround EX, extracting the rear surround information encoded in the left and right surround channels. With the Discrete variety however, the rear surround channel is encoded as a discrete, independent channel during mastering for home playback. DTS claims this results in more precise "steering" of rear surround information.

Although both varieties of DTS-ES are included in every AVR out there, DTS-ES program material is more scarce even than Surround EX.

DTS 96/24

A high-end breakthrough that allowed some DVD-Audio music discs and a very few DVDs to deliver 24-bit, 96-kilohertz quality for 5. 1-channels. Other than a few DVD-A discs released on DTS' own label, not many discs support this format. In addition, both DTS and Dolby have developed fully "lossless" codecs for Blu-ray and HD DVD that obviate this codec.

5.1 and Beyond

Dolby Pro Logic II, Pro Logic IIx and DTS Neo:6

Variations on a theme, these are surround sound "processing" modes that can expand two-channel stereo sources to 5.1-channels, or, in the case of Neo:6, expand 5.1-channel sources to 6.1-channnels in extended surround setups. Each includes sub-modes optimized music and movies. While the result is not the same as a source that was recorded in 5.1-channels to begin with, these modes can process a stereo recording in a way that often convincingly emulates the clarity, depth, and directionality, if not the pinpoint accuracy, of a true 5.1 presentation.

Dolby Pro Logic IIx is Dolby latest take on the technology, and expands the decoding from 5.1-channels to allow for either 6.1- or 7.1-channels.

Next-Gen Surround Decoding

High-definition movie discs bring with them a whole new generation of audio codecs to do justice to the amazing, state-of-the-art video. Blu-ray and HD DVD specifications allow for "up to 7.1 channels" of discrete— not matrixed—audio, but here again, 5.1-channels tracks are ubiquitous so far. The following codecs are prevalent on Blu-ray and HD DVD.

Uncompressed PCM

Because of the vast storage capacity of Blu-ray Disc, Sony and Buena vista have released their Blu-ray titles using uncompressed, multichannl linear PCM. This is essentially a higher resolution multichannel version of the coding used on the Compact Disc. Although uncompressed PCM takes up a lot of space, the results are astounding, and leagues beyond the quality of any of the lossy compression schemes.

 

Dolby TrueHD And DTS-HD Master Audio

Both of these are "lossless" audio codecs. Although the signals are compressed on encode, when decoded the signal is restored bit-for-bit identical to the original master. Both codecs are capable of encoding up to eight full range channels of audio, and resolutions as high as 24-bits at 192kHz.

Both of these are "lossless" audio codecs. Although the signals are compressed on encode, when decoded the signal is restored bit-for-bit identical to the original master. Both codecs are capable of encoding up to eight full range channels of audio, and resolutions as high as 24-bits at 192kHz

DTS-HD MA is optional on both Blu-ray and HD DVD. Thus far, no players from either camp offer DTS-HD MA decoding. The only next-gen software supporting DTS-HD MA are the Blu-ray Discs released by Fox.

Dolby Digital Plus

The apparent successor to Dolby Digital, this versatile codec is also a "lossy" compression scheme that is capable of operating at data rates both higher and lower than standard Dolby Digital. It is regarded as both more sophisticated and more efficient than its predecessor, and Dolby believes that it outperforms DD in lower data rate applications, such as broadcast HDTV, as well.

For high-definition packaged media applications (Blu-ray and HD DVD, in other words), Dolby Digital Plus tracks are typically encoded at either 640kbps or 1.5Mbps. DD+ tracks at 1.5Mbps are frequently used on HD DVDs from Universal and Paramount, and are often spectacular, offering a clear and obvious upgrade over standard Dolby Digital.

THX Post Processing

THX developed and licenses a variety of post-processing features to manufacturers of THX certified AVRs. These are referred to as "post- processing" because these are enhancements that are engaged after standard Dolby Digital and DTS decoding occurs. A movie on DVD is not encoded "in THX," in other words, it is encoded in DD or DTS and then THX adds some features once the soundtrack is decoded in the AVR.

Prominent among the THX feature set are RE-EQ, Timbre Matching, and Adaptive Decorrelation. Movie theaters and home theaters are very different as venues, and as a result the high frequency balance that is most appropriate for a large venue full of live bodies would be excessively bright in a home theater environment. RE-EQ tames this brightness, providing a smoother, more reasonable balance for home theater playback.

What to look for

Power Ratings (WPC) and Decibels (db)

ADs in the newspaper for an AV receiver, always lists the Watts-Per-Channel rating. One receiver has 50 Watts-Per-Channel (WPC), another one has 75, and still another has 100. The more watts the better right? Not Necessarily.

Most people think that more watts means more volume. An amplifier with 100 WPC is twice as loud as 50 WPC right? Not exactly. Read the following reference article for full details…

Sound level is measured in Decibels (db). Our ears detect changes in volume in a non-linear fashion. A db is a logarithmic scale of loudness. A difference of 1 db is the minimum perceptible change in volume, 3 db is a moderate change, and 6 db is doubling of volume.

For a Receiver to be twice as loud as another, you need 10 times more wattage output. A Receiver with 100 WPC is capable of twice the volume level of a 10 WPC amp. A receiver with 100 WPC needs to be 1,000 WPC to be twice as loud.

Build Quality

Quality of construction and workmanship play a vital role in creating an excellent receiver. A receiver built with bad parts is a bad receiver. Take note of the connectors on the backplane. Are they flimsy? Do the speaker terminals accommodate 12 gauge wire? How do the controls on the front feel? Are they well laid out? If you plan on spending $2600 on a receiver, ask yourself this question: Is the front door panel (if there is one) metal or cheap flimsy plastic? If not, it makes you wonder what else they skimped on internally.

Distortion (THD) – If It Doesn't Sound Good – The Watts Don't Matter

A Receiver that has excessive noise or distortion at loud volume levels can be unlistenable. You are better off with a receiver of about 50 WPC with a low distortion level than a more powerful amplifier with high distortion levels. A Receiver that has a distortion rating of 10% at full output is unlistenable. A receiver hat has a .01% distortion level at full output level would be excellent at all listening levels. Distortion specs are expressed by the term THD (Total Harmonic Distortion).

Signal-To-Noise Ratio (S/N) – Separating The Sound From The Noise

Another factor is Signal-To-Noise Ratio (S/N), which is ratio of sound to background noise. The larger the ratio, the more the desirable sounds (music, voice, effects) are separated from acoustical effects and background noise. In amplifier specifications S/N ratios are expressed in decibels. A S/N ratio of 70db is much more desirable that a S/N ratio of 50db.

Continuous Power (RMS) – Does The Receiver Deliver Over The Long Haul?

An additional factor is the ability of a receiver to output its full power continuously. In other words, just because your receiver/amplifier may be listed as being able to output 100WPC, doesn't mean it can do so for any significant length of time. Always make sure that, when you check for Specifications, that the WPC output is measure in RMS terms. This means that the listed power output is sustained output at a specific volume level.

Two Channel Fidelity

All right, so the receiver passed the noise test, what next? The amplifiers. In order for the receiver to be a winner, it has to deliver quality power for your speakers in the room size you are in and listening levels you are accustomed too. Pick speakers in the showroom as close to the ones you own or plan on buying. Put on a bass heavy CD. Listen to the bass notes for strain, boominess and lack of impact. If the receiver shares these characteristics, it is attributed to a weak power supply. This will be a problem for those with large tower speakers who demand bass output without the use of a powered subwoofer. Next listen to the midrange and high frequency spectrum. The midrange should have good balance throughout the 200Hz - 4KHz bandwidth free from excessive boosting or attenuation within the frequency spectrum. The high frequency spectrum above 4 KHz should sound airy, natural and not overly bright. Receivers which tend to sound bright must be carefully mated with speakers with a subtle nature in the high frequency spectrum.

Surround Sound Performance

Surround sound performance is a very critical issue that you must pay careful attention to. Listen to all of the surround formats available on the receiver (IE.DPL,DD,DTS) and verify there is no center channel bleed over into the other surround channels. You can accomplish this by listening to a movie with the center channel speaker on and the other speakers off. Familiarize yourself with the voices that are emanating from the center speaker. Now disconnect the center channel and reconnect the front speakers. Listen for bleed over of the voices to the main speakers. Next turn on all 5 channels and listen to a particular movie passage. Pay attention to how the sounds shift from one speaker to the next. Listen to this passage repeatingly until its familiarity is burned in your head. Compare its sound characteristic with the different receivers using the same speaker set-up to determine which receiver decodes the information best.

A Note About Bass Management

The receiver's bass management function re-directs the bass frequencies from any channel to those loudspeakers that can handle the low frequency bass information (e.g., full-range floorstanding loudspeakers, subwoofer). This ensures that the low frequency audio signals are not lost when you're using a system of bookshelf or satellite speakers. If you have five full-range loudspeakers and a subwoofer (few of us do), bass management is not a concern. But if you don't, it is essential that you look for a receiver with complete bass management functionality. With bass management, you set up your system by telling the receiver whether you have large (full range) or small (satellite or bookshelf) loudspeakers for the center channel, the two front left/right mains, and the surround sound channels.

Necessary Features

Aside from quality amplifiers and power supplies, features are one of the most important concerns when purchasing a receiver. You want the receiver you choose to purchase not only to sound good but to provide you with the features you need/desire. It is always better if you can buy a receiver with many A/V inputs and outputs both analogue and digital, and plenty of component / HDMI video switching. Does the receiver have the ability to upconvert all analogue inputs to component or HDMI? If it doesn't, you will have to use multiple cables/ inputs on the display in order to view all of your components.

Does the On-Screen Display (OSD) pass through the component video or HDMI ports? Are the on-screen displays (if this feature exists on the model you choose) intuitive? If not, you will be scratching your head often when attempting to optimize the performance of the system. Is the remote control complete with all function keys necessary to properly operate your system? And, is it easy to operate? If not, you will be investing in a multi-brand remote after many frustrating hours.

Do you need a 3D receiver?

If you want surround sound while watching 3D content, then yes. Without a 3D receiver you will be sending all your audio/video directly to your video display and that means all audio and video is being processed by the video display. Connect to a 3D ready receiver on the other hand and you are now processing the audio and video through the receiver and this is a good thing. The receiver can be programmed so it doesn’t touch the pristine 3D Blu-ray video quality and simply passes it through to the video display. 3D capable receivers are important. Think of a situation with a projector. Projectors do not handle audio. Therefore you must have a receiver that is 3D capable. Some 3D source components such as Blu-ray players will have two HDMI outputs on the back – one for video to your display device (TV, projector, etc) and one for audio to your audio device (receiver). In this case you wouldn’t need to have a 3D capable receiver.

Accessories

iPod Connectivity and Control

With the increasing popularity of the iPod, more receivers are equipped with iPod compatible connections, either via an adapter cable or a "docking station". What you should look for is, not only the ability for the iPod to connect to the receiver, but for the receiver to actually control all iPod playback functions via the receiver's remote control and menu functions.

Also, keep in mind that if you connect a Video iPod, you may only have access to audio playback functions. If you desire to access iPod video playback functions, check the receiver's user manual before you purchase to see if this is possible.

Networking and Audio/Video Streaming

Networking is a feature that more home theater receivers are incorporating, especially in the mid-to-high price point. Networking is executed via Ethernet connection or WiFi. This can allow several capabilities that you should check for. Not all networking receivers have the same capabilities, but some features commonly included are: Streaming audio (and sometimes video) from a PC or the internet, Internet Radio, and Firmware updating directly from the internet. To find out the networking and/or streaming features included in a specific receiver, check the user manual, feature sheet, or a review ahead of time.

Multi-Zone Audio

Multi-Zone capability is a function in which the Receiver can send a second source signal to speakers or a separate audio system in another location. This is not the same as connecting additional speakers and placing them in another room.

The Multi-Zone function allows a Home Theater Receiver to control either the same, or a separate, source than the one being listened to in the main room, in another location. For example, the user can be watching a DVD in the main room, while someone else can listen to a CD in another, at the same time. Both the DVD player and CD player are controlled by the same Receiver.

 

The Bottom Line

Don't base your buying decisions from a single specification, such as a Watts- Per-Channel rating. A single spec, taken out of context with other factors, does not give an accurate picture of the receiver's true capabilities. There are other factors to take into consideration, such as, sound quality, ease of use, and flexible connectivity with other components. Never buy a receiver without giving a listen for yourself.