Kabels: Cables and Connections


Home Theater Cables and Connections

Lesson 1: What HDTV buyers need to know about connectivity


In this lesson, you’ll get an overview of HDTV connectivity that will help you make smarter purchases, or get more out of HD gear that your currently own.

If you haven’t already purchased a high-definition television, it’s a good idea to educate yourself about how an HDTV connects to things. This information will give you a better idea of what to look for when you enter the retail jungle. And if you’ve already bought an HDTV, it’s still important to understand the basics of your components connection scheme, and ways you can maximize the effectiveness of your purchase.

Home Theater gear can have a large number of connection ports

Home Theater gear can have a large number of connection ports. Fortunately you generally won’t need to use them all, but it’s a good idea to know the purpose of each connection in order to get the most out of your system.

DTV vs. HDTV

Digital television (DTV) may be either standard-definition (SDTV) or high-definition (HDTV). Most DTV–delivery services offer a mix of SD and HD channels. But you’d be crazy to limit your video display to SDTV, so we’ll refer to sets as HDTVs.

What mode of DTV service will you use?

DTV is available via broadcast, cable, satellite, or your local phone company. To access over-the-air digital television, including HDTV, your set must have an ATSC-that is, digital-tuner. Federal law requires this, but some manufacturers cheat, so check anyway. Over-the-air analog channels require an NTSC tuner. For cable, either ask your local operator for an HD-capable box, or buy a digital cable ready TV with a CableCARD slot. For satellite or telco TV you’ll need a high-def-capable box from those outfits.

Other source components

To view HDTV on disc, buy either a Blu-ray or HD DVD player. There are combi players that handle both formats. To view HDTV on tape, get a D-VHS VCR. HD-capable DVRs are available from cable or satellite operators–or TiVo!

Connectivity

Don’t buy any HDTV without at least one HDMI input for each of your high-def source components. Avoid sets with the older DVI interface–it’s digital, but not fully compatible with some sources. Second best is component video, a high-def-capable analog connection. S-video and composite video are not high-def capable. A CableCARD-compatible set must have a CableCARD slot. An antenna-compatible set must have an RF antenna input.

Lesson 2: Overview of connections for a typical HT setup


In this lesson, you’ll learn more of the details of the complexity of a well-equipped home theater. It can seem daunting, but it helps to understand what’s feeding the system, and the basics of how the components are connected.

HD components look clean and simple from the front

HD components look clean and simple from the front. The depth of their connection possibilities is only revealed when you examine their back panels

Connect through HDTV or through surround receiver?

There are two ways to organize your home theater’s nervous system. If you want the best possible sound quality, make a surround receiver the switching heart of your system. Connect all signal sources to the receiver, letting the receiver feed the TV and speakers. If you have only a few signal sources, and are not fussy about sound, you might omit the receiver and connect everything to the TV. But relying on the TV’s speakers won’t give you a true home theater system–just a connected TV.

Placement

A video display should be placed far enough back to make the dotted pixels invisible. A surround receiver should sit atop the rack for best ventilation. If it must go in the middle of a tall rack, to reach the other components, allow at least three inches of space above it.

Audio/video signal sources

To get TV programming, you’ll need either an antenna, cable box, satellite box, or television service from a telco (telephone company). To watch disc or tape, you’ll need A/V source components. Note that if you want HDTV, you’ll need HD-enabled service or components.

Audio-only signal sources

While the up-and-coming HDMI interface handles both video and audio, audio signals from A/V components usually travel separately-via either digital or analog connections. A CD changer may use either type. Turntables require a phono input or phono preamp. Analog audiocassette decks need analog inputs and outputs to record and play. An iPod may connect via docking device or adapter cable.

Lesson 3: Connecting to TV-delivery sources


In this lesson, we’ll explore the ways to get many channels of DTV goodness into your system. TV-delivery sources may connect directly to the TV, to a converter/descrambler box, to a DVR, or to a combination of these things.

Antennas

Like digital TV in general, over–the–air HDTV is delivered mainly via the UHF band. You can find an antenna optimized for your location at AntennaWeb.org. Antenna signals are easily split to accommodate multiple TVs, DVRs, etc. Older TVs without ATSC tuners may require a separate tuner box to support broadcast HDTV.

Examples of HDTV antennas

Examples of HDTV antennas

Cable

Your friendly local cable operator would prefer you to rent an HD-capable box. However, thanks to an act of Congress, you’re allowed to go to a store and buy your own box. You may also demand a CableCARD for your CableCARD-compatible set. Be warned that the CableCARD standard is unidirectional, which means no video-on-demand. Bidirectional versions exist, though they’re not standardized–ask your cable operator about them.

Satellite

DirecTV and the Dish Network both offer HDTV packages. You’ll need an HD-capable satellite receiver to get them.

Digital video recorders

Cable, telco, and satellite operators all offer converter/descramblers with built-in DVRs at small extra charge.

Lesson 4: Types of video connections


This lesson gives you a quick tour of all of the possible video connections. The quality level of each video connection follows a pecking order. The options at the top of the list are the best.

The rear panel of a Sony Bravia shows a typical array of video input options

The rear panel of a Sony Bravia shows a typical array of video input options

HDMI

HDMI connectorStands for High Definition Multimedia Interface. As the most common digital video interface, it’s the best way to connect anything to an HDTV. Unfortunately, multiple versions and other snafus make HDMI problematic. Go here for more details about HDMI.


DVI

DVI connectorStands for Digital Video Interface. This an older and now obsolete form of HD-capable digital connection. As a forerunner of HDMI, it may work with some HDMI gear via adapter-then again, it may not!


IEEE 1394

firewire connectorAlso known as FireWire (Apple) and iLink (Sony), this digital interface also carries both video and audio, and is recordable, but is relatively rare in home theater systems.


Component video

component connectorThis HD-capable analog interface is the next best thing when HDMI and DVI are not available (or functional). It uses a trio of red, green, and blue color-coded connections.


S-video

s-video connectorThis round multi-pin plug carries analog video signals-not DTV. However, it does a fine job of it by separating the brightness and color parts of the signal. It’s fine for legacy components.


Composite video

comp-video connectorThis yellow color-coded plug also carries analog video signals. Because it mixes the brightness and color signals together, it produces a smeary picture. But it’s the next best thing for analog legacy components like VCRs when S-video is not available.


RF

RF connectorResembling a threaded bolt with a pinhole, this jack connects television sources such as antenna or cable, and will be labeled specifically for one of those purposes. If you have a standard cable package, a CableCARD-enabled set will require the card to handle encrypted channels. If you have a broadcast basic cable package, the set will handle at least the unencrypted analog channels, and possibly also the unencrypted digital channels if it has a QAM tuner.


The special problems of HDMI:


HDMI is the best way to get a digital video signal from any source to your HDTV. It can also carry sound, with video and audio united in a single convenient cable. But you’re most likely to use it just for video. The bad news about HDMI is that there are multiple versions and much confusion surrounding them.

HDMI provides the highest possible resolution

HDMI is the video port which provides the highest possible resolution

Background

HDMI originated as a Hollywood-approved video interface and an alternative to the less secure IEEE 1394. Unlike 1394, HDMI cannot be used for recording. Studios and TV makers were both heavily involved in the creation of HDMI.

Versions

All versions of HDMI, starting with 1.0, carry video to feed a display and stereo audio to feed TV speakers. Version 1.1 adds support for the nearly defunct DVD-Audio format. Version 1.2 supports the Super Audio CD. Version 1.2a brings the convenience of CEC (Consumer Electronic Control) which simplifies an a/v system’s operation by allowing components to talk to one another. Version 1.3–a very big deal–supports superior color palettes and lossless surround formats delivered via Blu-ray or HD DVD. Let’s discuss the latter in more depth.

Surround via HDMI

The following is an extreme but necessary oversimplification. Only HDMI 1.3 carries all known surround formats between a disc player and receiver at full resolution. That includes new lossless formats supported by Blu-ray and HD DVD, such as Dolby TrueHD and DTS-HD Master Audio. So if you’re buying a surround receiver, make sure it’s got HDMI 1.3. But there is a workaround. Most Blu-ray and HD DVD players have built-in surround decoders. Connect their multi-channel analog outputs to your receiver’s multi-channel analog inputs and you’re in business.

Copy protection

HDMI and DVI both support copy protection known as HDCP (High-bandwidth Digital Content Protection). The set and sources perform a handshake. If a device is not HDCP-compliant, the TV will not display a picture. This is a problem with some DVI equipment.

Upconversion

This round multi-pin plug carries analog video signals-not DTV. However, it does a fine job of it by separating the brightness and color parts of the signal. It’s fine for legacy components.

Composite video

Some receivers route incoming signals from all jacks to the HDMI output, allowing a convenient one-wire connection to the video display.

Lesson 5: Types of audio connections


Beyond the obvious need for speaker cables, audio signal sources have a pecking order of their own.

A typical wiring diagram for a 7.1 surround sound system

A typical wiring diagram for a 7.1 surround sound system

HDMI

As discussed previously, HDMI can carry audio as well as video signals–but you’ll need to get the latest version, 1.3, to be fully up to date.

IEEE 1394

This audio/video interface is occasionally used for the high-res audio formats, Super Audio CD and DVD-Audio.

Digital, optical and coaxial

These digital interfaces support lower-resolution audio signals. Their main use is to carry Dolby Digital and DTS 5.1 plus CD audio from regular DVD and CD players.

Analog 5.1–and 7.1–channel

An older receiver without HDMI can accept surround signals in any format through these analog multi-channel inputs, as long as the source component feeding it has a full set of analog outputs.

Analog stereo

TColor-coded white and red, old-style audio jacks are useful mainly for connecting analog legacy components such as stereo VCRs and phono preamps. To make a tape deck fully functional, you’ll need stereo ins and outs, sometimes labeled “tape loop.” A CD changer can work through either digital or analog outputs.

Phono

If you plan to play vinyl records through your system, your receiver needs a special input to accept the low-voltage signal from a turntable. A receiver’s phono input may be solely for moving-magnet cartridges, or may be switchable for both moving–coil and moving–magnet types. A ground terminal may be provided to defeat turntable hum. If you don’t have a phono input, you’ll need a separate phono preamp.

iPod dock

Docking devices offer better sound quality because they bypass the iPod’s volume-control circuit. They also charge the player, and some offer an onscreen interface via the receiver. But you can connect an iPod directly to your receiver with a simple adapter cable having a mini-plug at one end and two RCA plugs at the other.

USB

Some non-iPod music players output to a receiver through the USB interface.

AM/FM

Analog radio requires different antennas for AM and FM. That’s why the receiver has separate inputs for each of them.

XM/Sirius

Some receivers have dedicated inputs for satellite radio. The antenna is usually a $20 accessory.

Loudspeakers

Use 12- to 16-gauge speaker cable. Better speakers and receivers have binding posts which screw down securely on the cable tip. Cheaper ones have wire clips, which are fragile and don’t provide as secure a connection. To prevent cables from corroding, you may have them terminated in gold-plated banana plugs, spade lugs, or pins. However, new slim speakers are often designed to work only with bare wire snaking down their slender columns. See tutorial on connecting speakers.

Lesson 6: Miscellaneous considerations



This lesson covers miscellaneous components and issues related to your home theater’s connections.

Are premium cables worth it?

Find the happy medium between flimsy generic wire and the mind-bogglingly expensive stuff. You want your cables to be sturdy, well-insulated, but no more than 15 percent of the price of the components they’re connecting.

Power-line conditioners

A generic surge protector won’t do. Your system needs high-current outlets for the power-sucking display and receiver. It also needs isolation transformers to defeat ground-loop-induced hum. So buy a high-quality power-line conditioner. Don’t even think of using a cheap power strip–it will only hobble your system, and leave your system vulnerable to potentially damaging power surges.

A power line conditioner filters out noise and hum that can detract from your system's sound quality

A power line conditioner filters out noise and hum that can detract from your system’s sound quality

A/V furniture

Does that equipment rack have room for all your legacy components? Do those speaker stands position tweeters at ear level? Does that flat-panel TV mount allow tilting to the ideal viewing angle? And is that TV stand rated for more than the weight of your set?

Cable management

A busy rack needs a way to keep cables under control. One simple idea is a hole in the back of each shelf, funneling cables up or down as needed.

Hiding wires

If style concerns make you leery of rear-surround speaker cables, or you want your elegant flat–panel TV to float free on the wall, a capable custom installer (or even an electrician) can make that ugly wiring disappear. Unless you’re handy with things like stud finders and fish tapes, let a pro do it.

.

 CluB Webmaster: John Riegen / Harry van der Burgt