Distributed Audio Systems by Covan Home Systems

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AUDIO : THE BASICS

So you're ready to upgrade from a boom box to a real home audio system. While selecting a good system isn't as difficult as buying a new house, there are many things you need to consider when creating your music and home theater experience. This step-by-step guide will help simplify your audio buying. The first thing you need to determine is what your you want your audio system to do.

Stereo A basic stereo system consists of a source (usually a CD or DVD player, though every DVD player can play CDs), a stereo receiver or pre-amp and amplifier, and two speakers. Stereo systems with small speakers will usually need a subwoofer to handle the low frequencies, while full-range tower speakers can often handle all the audio frequencies by themselves.

Distributed Audio Distributed audio systems can be extremely complex or relatively simple. A simple system utilizes a receiver with multi-zone capabilities and several sets of speakers distributed around the house. Sometimes each zone will be driven by a separate amplifier built-in to the receiver. Other systems only have a pre-amp stage and require separate stereo amps for each zone. Some multi-zone receivers are also multi-source, which means that you can send music from the CD player to one room while listening to your TV in another.

Advanced distributed audio systems include dedicated multi-zone and multi-source controllers and sometimes audio servers with hard drives packed with music. These systems almost always require professional installation. Here a good demo is key.

AUDIO : HI-RES SOUND

High-resolution audio can be many things to many people. That's because more than one format is considered high resolution. This can be confusing, but it's worth it to hear audio that sounds far better than conventional CD-quality music. If you want to get into high-resolution audio, but wish to remain format agnostic, it may be wise to buy a universal player that supports all the formats. Other than that, be prepared to look for the right logo when you buy your music.

	DVD Music DVDs hold higher-quality audio than CDs. Where CDs are mastered at a 16-bit/44.1 KHz sampling rate, DVDs are mastered at a 24-bit/48kHz rate. The difference is noticeable to the naked ear. On top of the better sampling rates, many DVD movies and music titles are recorded in 5.1 surround sound (using Dolby Digital or DTS). For live music titles, this is often used to create a live-at-the-concert feeling. DVD movies have the benefit of high-resolution sound, but there are some music-specific titles, too, that include video to go along with the music. Naturally, this format works on all existing DVD players.
	DVD-Audio DVD-A is often mistaken for DVD music, since both formats use DVDs as their storage medium. But they are very different inside. DVD-A audio uses a sampling rate up to 24-bit/192kHz (96kHz in multi-channel) and something known as MLP "lossless compression" to deliver sound quality that is far better than CD and technically better than DVD music. And like DVD, DVD-A offers multi-channel music. Because DVD-A takes up a lot of space on a disc, only small bits of video are possible, the rest of the disc extras are typically limited to still images or artist discographies. Unlike DVD music, the player must be able to play back the DVD-A format. Unfortunately, not all players do. However, most DVD-A titles carry a PCM layer (the format of CDs), which holds CD-quality tunes that all DVD players can read. Even though they have a PCM layer, DVD-A discs cannot be read by CD players.
	Super Audio CD SACD uses a process called direct stream digital (DSD) to achieve a sampling rate of 2.82 MHz, which is 64 times that of CD. To some critics, SACD sounds better than DVD-Audio; to others it's a toss-up. Regardless, both formats produce audio that is superior to standard CD. Like DVD-A, SACD can only be played back in players that support SACD. Though SACD started out as a two-channel format, most players and many titles now offer multi-channel playback. There are also hybrid discs that include a PCM layer for playback on conventional CD and DVD players but, again, you won't hear the higher resolution audio tracks on these discs.

What Goes into a Speaker

Speakers generally have two or more drivers to handle different parts of the frequency spectrum, and these drivers can be made of several different materials. Metal (aluminum or titanium) is the fastest material for tweeters. Other materials you'll see on spec sheets include polypropylene (plastic), textiles (silk dome tweeters), bulletproof materials (Kevlar woofers), and paper (usually treated with something to make it tougher). There are also composite materials like laminated titanium/plastic and anodized aluminum/ceramic.

Don't assume you'll automatically get long-term listening satisfaction from metal tweeters and bulletproof woofers. Good speakers can be made of practically anything. Each kind of material has its own breakup mode, so regardless of material, the designer has to know what its limitations are and how to minimize them. For both speaker designers and speaker buyers, there's no substitute for a good ear.

The terms two-way and three-way refer to the number of drivers. A two-way speaker has a single crossover (between tweeter and woofer) while a three-way speaker has two crossovers (from woofer to midrange and from midrange to tweeter). The more crossovers, the less linearity, so don't assume a three-way speaker will always outperform a two-way model. - Mark Fleishmann

Bipole and Dipole

Any speaker can be used for the surround channels in a 5.1, 6.1 or 7.1 home theater set-up. But some believe the theater experience can be enhanced with bipole or dipole speakers. The designs for these are similar and sometimes a single speaker will be designed to switch between the two types.

Bipole speaker have two drivers - not aimed at the listener - that are placed on opposite sides of the speaker cabinet. They work in phase (send out sound at the same time) and tend to diffuse the audio, using room acoustics to fill the room with sound.

Dipole speakers start with the same design as a bipole, but the drivers operate out of phase. This creates sound that is even more spread out than that produced by a bipole. Localized sounds, however, such as a specific sound placed in the surround channel on a movie sound track, can lose their effectiveness through dipole speakers.

AUDIO : COMPONENTS

Audio systems come in two flavors: All-in-one, do-everything boxes and separate components. All-in-one boxes are simple systems that save space but usually sacrifice performance and upgradeability. Unless you value space saving and simplicity over everything else, then a component system is always the best way to go.

Separate components provide more features and flexibility, are usually made of high-grade parts and are easier to upgrade since you can swap out an individual component rather than the whole system.

A typical component system consists of a source, usually a DVD or CD player, a controller/source selector, a pre-amp/processor and an amplifier, although there are plenty of systems out there that do without the separate pre-amp/processor and amp and use a single surround sound A/V receiver.

Source A source can be anything from a cable box to a turntable, DVD player, CD player, radio tuner, media server, iPod dock, etc. Generally, a DVD player will play all your pre-recorded audio and video, with the best DVD/CD players handling multichannel audio formats such as DVD-Audio (DVD-A) and Super Audio Compact Disc (SACD). DVD-A and SACD offer greater sound resolution than standard CD audio discs and surround sound.

Other features to look for in a source include CD-R playback so you can listen to your home-burned CDs, and the ability to play all the MP3 and WMA files that you've ripped and downloaded. On the video side, if you have an HDTV then look for a progressive scan DVD player that upconverts video signals to HD resolutions and connects via DVI or HDMI.

Receiver Receivers, either stereo or surround sound, are a combination of a pre-pro and amplifier. They almost always include AM/FM radio tuning as well. It is getting more common to use a receiver instead of a pre-pro/amplifier system (see below), but the best results and most flexibility will still be had from separate components. When shopping for a receiver look for the same features described for pre-pro/amp systems. Keep in mind, however, that some lower quality receivers provide misleading power specs. When evaluating wattage, make sure the power is listed as "all channels driven," which indicates that a 100-watt per channel receiver, for example, provides 100 watts on all of its channels at the same time rather than 100 watts only in stereo mode but less in surround mode.

Pre-pro/Amplifier Systems include a pre-amp/processor (sometimes called a pre-pro), which is the central nervous system of this type of audio setup. and an amplifier, which is the muscle of the system. You can search the web for additional info on pre-processor/amplifier Systems.

Optional components

Integrated Controlled Bass Manager: Some systems can benefit from an extra component for bass management, particularly if the receiver or DVD-Audio player does not provide sufficient bass management features.

Video processor: For scaling, improving and aspect ratio control of the video image.

Turntable: Yes, some people still use them. Make sure your pre-pro or receiver has a phono input or purchase a phono amp separately (these are inexpensive).

Multi-zone controller: Most high-end receivers and pre-pros are multi-zone compatible, but if it isn't this component will fit the bill.

Satellite Radio Tuner: Several high-end audio companies offer satellite radio components for the home. The best are designed for multi-zone use.

Power Enhancer: The real juice of an audio system comes from the electricity powering it. Unfortunately most home AC supplies are inconsistent and riddled with interference. AC filters, power enhancers and voltage regulators can make a big difference in how your system sounds and performs.

AUDIO : CONNECTIONS

The back of every audio system is dotted with numerous connections of every shape and size. To figure out what goes where, it helps to break down this hodgepodge of plugs and jacks into three types: Audio interconnects, speaker wire and video interconnects.

Audio interconnects Audio interconnects link the main components up to each other and come in two types: analog and digital. Standard red and white stereo cables are analog and almost always use RCA style plugs. Digital interconnections can be either the coaxial type or the fiber optic type (also called Toslink).

A digital interconnect is the preferred way to connect digital sources such as DVD players and HDTV set-top-boxes to your preamp or receiver. Coaxial types use copper wire and terminate in a standard RCA plug and optical interconnects use thin fiber optic lines that emit light when the source is powered. Some people will argue that coaxial is superior to optical, though few listeners will be able to tell the difference.

Optical cables require delicate handling since the terminations are sensitive and the wire can't be bent too far without snapping.

The only time a digital connection shouldn't be used is when connecting a high-resolution audio player (DVD-A or SACD) to a pre-pro or receiver. DVD-A and SACD signals cannot be passed through a standard digital interconnect so you have to use analog connections for all five speakers plus the subwoofer.

Speaker wire Some of the most important connections in an audio system run between your amplifier and your speakers. The gauge, quality and termination on the wire make a big difference in how a system sounds. Good cables allow a system to perform at its highest level without coloring the sound.

Loudspeaker cable is available in varying gauges, such as 18AWG (American wire gauge), 16 AWG and 14 AWG. A smaller AWG number means a thicker cable. 14 or 12 AWG are good sizes for most quality audio systems - it's a good idea not to go smaller than 16 AWG, though. Very high-end systems sometimes call for speaker cable the size of garden hoses. If cables need to be run though walls, they must be UL rated for fire resistance. Better quality cables are made of higher grade copper, use better shielding and dialectics and are more durable.

The speaker wire can be connected to the amp or receiver in various ways. Good amps and receivers feature five-way binding posts, rather than cheap spring clips, for connecting speakers. The high-end ones are nickel- or gold-plated and allow for ample maneuvering room for your fingers. Five-way posts can accept bare wire, banana plugs or spade lugs. Banana plugs and spade lugs are superior to bare wire connections.

Many high-end speakers allow for bi-wiring, which refers to running two lengths of wire from the amp to the speaker. In this case, one pair of cables will connect to the speaker's tweeter crossover while the second connects to the woofer crossover.

Video Interconnects Audio systems that are also used for video, such as home theater systems, must also feature an assortment of video connections. Basic video interconnects are composite, S-video and component. HDTV set-top boxes may also feature DVI or HDMI connections, and some receivers and preamps are starting to include those connections as well. Better quality receivers upconvert lower quality video signals from composite and S-video cables to component and even HDMI quality. HDMI cables actually carry both audio and video signals.

AUDIO : FORMATS

The number of audio formats keeps increasing, so it's important not to get overwhelmed. Choose formats that will let you experience audio in a way that matches your lifestyle. Surround sound formats come in several different flavors. Dolby is the de facto standard, while formats from DTS and SRS Labs offer some interesting alternatives. Several of these audio formats deliver the full home cinema experience DVD offers. A few of them even turn two-channel music into surround or create surround sound without the extra speakers.

	This is the standard format for 5.1 surround sound on DVDs and is found on all surround sound A/V components. It decodes the 5.1 sound track on a DVD, creating audio that is delivered from five speakers: Left and right front, center channel and left and right surround and a sub-woofer.
	EX bolsters surround sound by adding a channel, often referred to as the rear or back channel. But the DVD has to be encoded with EX as well to get the full experience. Receivers supporting EX are referred to as 6.1 receivers, or even 7.1 receivers because they split the back channel into two speakers.
	Pro Logic was the preferred method of achieving surround sound before the advent of Dolby Digital. Pro Logic II is an extension of its father format and is able to take two-channel audio (CDs, MP3s, broadcast TV or VMS tapes) and turn it into 5.1 audio. A further version called Dolby Pro Logic llx does the same thing but turns it into 6.1 or even 7.1 audio. It can also take 5.1 and add a rear channel, though it won't be as complete as a true 6.1-encoded soundtrack.
	This technology creates 5.1 where only two speakers are present. This is not true 5.1, but rather, a psychoacoustic method of tricking the ears into thinking sound is coming from all around them, rather than just in front. Sometimes this is called virtual surround sound. A similar version of this technology, called Dolby Headphone, works on headphones. DTS' method of creating 5.1 surround sound. It claims to offer a higher quality 5.1 soundtrack by correcting what the company sees to be inconsistencies in standard 5.1 decoding. It can be found on many DVD, game and audio titles, as well as A/V components, but it is still considered an optional format.
	The DTS' format for 6.1 surround sound, which adds a rear channel, decodes both prerecorded matrix 6.1 and discrete 6.1 audio. Discrete delivers a complete rear channel, rather than one that is matrixed from the other two surround channels, as is the case with matrix 6.1.
	Neo:6 can take two channel audio and turn it into 6.1 channel audio. It is offered with DTS-ES A/V receivers and can be found in car audio equipment, as well.
	This format is used to create some high-resolution DVD music discs. The number stands for the sampling rate of the audio-24-bit/96kHz. It can be found on mid- to high-end receivers that feature DTS.
	DTS Virtual takes DTS 5.1- or 6.1-channel soundtracks to stereo and creates a virtual impression of surround sound for a two-channel configuration. It will also work with headphones.
	SRS's CS takes two-channel audio and creates 5.1 audio. It also decodes CS-encoded material. There are only a handful of DVD titles with CS encoding, but several broadcast television stations use CS to deliver surround sound (CS-encoded material can be decoded by Dolby technology, too). Like DTS, it is not a standard feature on all surround sound receivers, though several well-known audio manufacturers include SRS technologies on their equipment.
	CS II does the same thing as CS, except that it bumps two-channel up to 6.1 and claims other improvements, such as better dialog clarity and better bass. There is a version of this called CS Automotive, which can be found in some car audio equipment.
	The improved version of SRS' original TruSurround technology, XT takes 5.1 or two channel music and delivers virtual surround sound from two speakers. It includes SRS WOW, a technology found in some television sets and portable audio players that creates a 3D effect for stereo. It also claims enhancements to both dialog clarity and bass. SRS offers a version for headphones called TruSurround Headphone.

AUDIO : DIGITAL MUSIC

Much to the dismay of high-end audio dealers, one of the biggest things to happen to the audio world recently is the arrival of MP3 and other compressed audio formats such as AAC, WMA, ATRAC. These compression schemes take standard CD music files and squeeze them down to a much smaller size, much the same way the JPG format compresses digital pictures.

Many audio buyers now believe that MP3 is the only thing they need for music. Compression works by eliminating some of the audio information. This results in music files that can be downloaded. If you value the quality of your music experience, you shouldn't settle for PC sound.

Pros: The up side of MP3 is that you can fit a lot of music in a small amount of space. The 30GB portable hard drive in the iPod can store 5,000 songs. The small size of the files also makes them easy to share over internet connections.

Cons: The down side of MP3 and other formats is that the compression process degrades the audio quality of your music. For portable listening through headphone or earbuds, the loss in audio quality is usually not significant, but the degradation will be easily apparent when listening through a good home audio system. The most noticeable loss is in bass and soundstage quality.

Even files compressed at 128kbs exhibit obvious sonic loss. Claims of CD or near-CD quality are very misleading. The point to remember is that compressed music formats cannot sound as good as the original. If sound quality is important to you, you won't compromise your critical listening with compressed music.

Digital Rights Beyond the sound quality of compressed music, there are legal issues to consider when acquiring and using compressed music. It is legal to make burned copies of your own CDs for your own use and to load them onto your portable player, but distributing them in any other way is illegal, as is making a copy for a friend or making it available on file sharing web sites. Downloading compressed music from legitimate pay music sites like Napster, iTunes, and eMusic is fine, and legal, but many download sites place strict limits on how the downloaded files can be used, how many times, if any, they can be burned and what devices can play them.

Compression Confusion Just about every compressed audio format has a big company pushing it as an industry standard. The stakes are high since the most popular format gains more control over music distribution and, more importantly, patent royalties for the company behind it. While MP3 was king for a while, it is taking a back seat to codecs like AAC and WMA. These new formats sound better than MP3 and offer built-in copy protection, but none are as universal.

It is bound to get confusing as more people move to buying music from the web. What music fans buy one day may not work on equipment they buy another day. Here's a brief guide to the most important formats.

MP3 MPEG-1 Audio Layer 3, more commonly referred to as MP3, is an audio encoding format. The major problem with MP3s is the lack of copyright protection. You may not care, but the music industry sure does. Some music download services offer MP3 downloads, others are going to the WMA and AAC formats. It uses a lossy compression algorithm designed to greatly reduce the amount of data required to represent the audio recording, yet still sound like a faithful reproduction of the original uncompressed audio to most listeners. The compression removes certain parts of sound that are outside the hearing range of most people.

AAC Advanced Audio Coding (AAC) is a standardized, lossy compression and encoding scheme for digital audio. AAC is promoted as the successor to the MP3 format by MP3’s creator, Fraunhofer IIS. Depending on the encoder used, AAC generally achieves better sound quality than MP3 at the same bitrate, particularly below 192 kbit/s. AAC’s most famous usage is as the default audio format of Apple's iPhone, iPod, iTunes, and the format used for all iTunes Store audio (with extensions for proprietary Digital Rights Management (DRM) where used). AAC is also the standard audio format for Sony’s PlayStation 3 and the MPEG-4 video standard. (info from Wikipedia)

WMA The long name for it is Windows Media Audio - an audio data compression technology developed by Microsoft as a competitor to the popular MP3 and RealAudio codecs. It is a proprietary technology which forms part of the Windows Media framework. Today it is one of the most popular codecs, together with MP3 and MPEG-4 AAC. In 2003 it came second after MP3 in terms of standalone players supporting it. WMA Pro, a newer and more advanced codec, supports multichannel and high resolution audio. A lossless codec, WMA Lossless, compresses audio data without loss of audio fidelity.

ATRAC3 Adaptive Transform Acoustic Coding (ATRAC) is a family of proprietary audio compression algorithms developed by Sony. MiniDisc was the first commercial product to incorporate ATRAC in 1992. Today ATRAC is used in many Sony-branded audio players. Improvements to the codec in the form of ATRAC3, ATRAC3plus and ATRAC Advanced Lossless followed in 1999, 2002 and 2006 respectively. On August 30, 2007 Sony announced that its online music store, Connect Music Services, would no longer support the ATRAC audio format.

- Natalie Hope McDonald is the author
of much of the content on this page

AUDIO : BUYING TIPS

Think of your audio system as a lifestyle purchase, like a vacation or a car, rather than a product like a telephone or a microwave. An audio system should reflect the way you live, where you spend your time, how you listen to music and watch video and who's with you when you use the system.

If family entertainment is your main focus, then a home theater system is probably the direction you'll want to look. A home theater system will combine the right audio components for listening to music and enhance the entertainment experience of HDTV and DVD. Very few people will have the space and money for a dedicated home theater room - designed exclusively for that purpose. Most people, however, will want to integrate a home theater sound system into a general purpose area such as a living room or family room.

If multiple people will be using the system, make sure the control system is easy to understand. Time spent teaching and re-teaching family members how to use complicated remotes leads to frustration and takes away from the enjoyment.

Even if the primary interest is music, a home theater system is often still the way to go. First, it's more versatile. One family member may only want to listen to music in that room, but others may appreciate the opportunity for DVD viewing. In addition, the best new music formats are all multi-channel and can only be fully appreciated in a home theater configuration. If you're investing in high-end audio equipment, you don't want to miss out on the benefits that SACD and DVD-Audio bring to the table.

Dealer/customer relationship A good audio system is something you will live with, enjoy and share for many years. As a quality audio dealer, Covan is your partner in the decision-making process. We will be there to help you learn to use your products and upgrade when the time comes.

Brand shopping First-time customers are often astounded by the variety of brands, particularly ones they've never heard of before. Many high-quality audio products are made by companies that specialize in just those products and supply their products only to specialty dealers like Covan who understand them and know how to match the products to the consumer's needs. When consumers shop by brand alone, they may miss out on some really great products.

Listening demo Remember that any product will probably sound slightly different in your home than it does in a showroom because audio quality is effected by the room size, walls, carpets and other structures in the room. Newly purchased products will likely need a break-in period, so don't expect exactly the same sound right away (bright speakers will often warm up after break-in).

Dynamic range A wide dynamic range means your system is capable of a wide range of audio frequencies from highs to lows. A good dynamic range means it can more faithfully reproduce your music.

Soundstage You should get the impression of three-dimensionality when listening to music. If you can close your eyes and pick out where the different instruments are coming from, that's a sign of good soundstage. The speakers should essentially disappear.

Dispersion Dispersion is related to soundstage in how the speaker throws sound out into a room. Speakers with narrow dispersion patterns will have a narrow sweet spot where the sound quality is best. Move from that sweet spot and the quality of the sound changes greatly. If the listener is always going to be in the same spot (a sofa for example), then speakers with narrow dispersion will work. If a wider sweet spot is required then speakers with a broader dispersion will be needed.

Treble and mid-range High (treble) and mid range tones should be uncolored, without either an echo, tinny or bright effect. Pay attention to vocals, pianos, cymbals and acoustic guitars.

Bass accuracy All too often cheap home theater systems produce bass that sounds muddy and dull. Listen for detail and accuracy rather than one deep rumble note. Big subs are not always better. Many well-designed 8-inch subwoofers will outperform cheap 12- or 15-inch subwoofers. Sometimes the less is more rule works well with bass. Kick drums and cellos should be tight, not dull.

Distortion Distortion is most apparent at high volumes. Turn the volume up to the highest level at which you expect to listen, and pay attention to any distortion of the sound quality.

AUDIO : FREQUENTLY ASKED QUESTIONS

Q Doesn't MP3 sound as good as CD?

A No, the nature of compression means that some audio information is deleted in the process of turning a CD file into an MP3, WMA, AAC or any other compressed format. Some sound better than others, and higher bit rates sound better than lower bit rates, but nearly anyone will clearly hear the difference in a side-by-side comparison.

Q Isn't high-quality audio very expensive?

A Not always. Some very expensive products perform no better than products half their price, while some are worth every penny. That's why it's important to experience a wide range of products, listen to the advice of a quality dealer, and listen to the products themselves.

Q How much power do I need?

A There's a lot more to an amp than simply how many watts it delivers. Powerful amplifiers are important, but not just for making your system loud. You need enough power to drive your speakers, so sensitivity or efficiency is just as important as wattage. A less efficient speaker (measured in decibels) requires more power from the amplifier. Conversely, a more efficient speaker requires less power to be driven at the same volume. Higher wattage isn't just about volume. A more powerful amp will deliver more dynamic range and detail to your music, even at lower volumes. You also need to match the speakers' impedance or resistance to that of the receiver. Low impedance speakers will require a more powerful amplifier. Also look at the total harmonic distortion, the amount of noise generated by the amp/receiver. The lower the number the better. Amps and receivers capable of high current power are better able to reproduce the peaks and bursts in music and soundtracks that can be particularly demanding of audio equipment.

Q Don't speakers have to be large to sound good?

A No. Large speakers have the benefit of having a wider dynamic range, but subwoofer/satellite combinations can have as wide a range but in much smaller packages. A lot depends on the speaker design and the materials, as well as the quality of the amplifier and subwoofer.

If you or your spouse object to the sight of speakers placed around a room, then consider a system involving in-wall or in-ceiling speakers. Today's in-wall/in-ceiling can sound nearly as good as traditional speakers, and are much less obtrusive in a room. In-wall subwoofers are also available so home theater systems can still get the benefit of deep LFE without a large enclosure.

Q How is speaker placement important?

A Speaker placement can be very important, especially in home theater systems with subwoofers. Speaker placement affects sound-stage and can also affect bass quality. Some speakers work best placed away from a wall, while others can be placed right on a wall (or even in one]. Subwoofers tend to get "boomy" when placed in corners. Many speakers benefit from toeing in - turning the speakers in a few degrees. The best advice is to experiment with placement.

Q Why are separates better than combination products?

A While all-in-one systems are attractive because they require less setup time and fewer remotes, the user experience isn't always significantly easier than separates. Separate components are usually built of higher quality parts, often can be more customized to the user and offer an easier upgrade path than all-in-one systems. Universal and programmable remotes - usually a feature of higher-end products - make using separates as easy as all-in-one products.