When putting together a home theater system, there are multiple connector types that you will come across. Each different piece of equipment that you have will have at least one of these types of connectors. It is important to know what the pros and cons are for each type of connector so that you can put together the best home theater that you can with the best picture and sound quality available.
Composite Video: This is the standard connector type that pretty much all TVs and A/V devices have nowadays. It uses the standard RCA type connectors with one wire for video which is usually yellow, accompanied by one or two audio wires which are usually white and red. Red is usually the right audio channel. You can remember this because red and right both begin with the letter ‘R’. Composite video connections are analog so they are subject to distortion and interference. This means that it is important to keep these wires away from most other wires, especially high voltage power lines. It is typical to run the power cables on one side of your home theater system and the signal cables on the other side to reduce any interference. If you do not do this correctly, you can get bad signal quality which will either distort your video signal or cause a whine or other strange sounds in your audio signal. This happens with any analog wiring, including S-Video or Component connectors as described below.
S-Video: This is one step up from composite video, it uses one physical cable but has two pairs of wires inside. This has slightly better quality than composite cables, but does not provide High Definition signals. Many older devices such as VCRs or older DVD players and cable boxes have S-Video connectors on them, and most new TVs have one S-Video connection on them, but most TVs do not have more than one connector for S-Video on them. If this is the highest quality connection on a piece of equipment you should use it, but if you have component video, HDMI connectors or something better you should use that instead.
Component Video: Similar to how S-Video is one step up from composite video with an extra pair of wires, component cables use three pairs of wires with three physical wires for the video connection. This can be accompanied by analog audio connectors, which are red and white similar to composite videos, or a type of digital connection such as those described further on in this article. Component video cables usually have red, green, and blue connectors for the three video wires. Although component cables still use analog signals, they can either carry higher quality standard definition signals, or they can carry either 720 or 1080 high definition signals if you have compatible equipment. This is the best quality video signal in analog form and most first generation HD products use this type of connections, but has mostly been replaced by HDMI in new HDTVs and A/V equipment. Most new TVs have at least one set of component cables on them with some having two, or three sets.
HDMI: This is the latest and greatest type of connector available for home theater systems. HDMI allows multiple signals to be carried over one cable. This means that High Definition video and surround sound audio can be sent on the one HDMI cable, as well as control and content protection signals that can tell your A/V system certain things such as which resolutions are supported as well as if content protection is enabled or not. Content protection tells you’re A/V system to not allow you to record certain movies or other content with a VCR or DVR. Sometimes this will cause problems with some A/V setups, but most of the kinks and bugs have been worked out since the inception of this technology so that most setups work flawlessly. HDMI is pretty much the de facto standard of home theater and other A/V setups across the board. If you buy a new TV or piece of equipment such as a Blu-Ray player, you can pretty much guarantee that it will have at least one HDMI connector. Most new TVs have 3 or more HDMI inputs and some even have HDMI outputs so that you can output audio signals to a sent to an audio system. This is useful if you don’t want a full blown home theater system but still want to use additional speakers or subwoofers. This is good for adding much needed low end and more fidelity to the sound of your home theater system without too much wiring or other complications. Some systems include as few as one speaker, usually called a sound bar that is installed directly above or below the TV, while others may have two speakers that go on either side of the TV and a subwoofer that can go pretty anywhere in the room. With all the features and the ease of installation, running wires, and having to plug in only one wire for an entire HDTV system, you can see why HDMI is so popular nowadays. If you can use HDMI for any or all of your devices, than by all means do so. If you don’t have enough HDMI connections on your TV or A/V receiver, you can get a switcher box, which allows you to switch between multiple outputs – most usually have 2 or 4 inputs, but some have even more. Or if you do not want to buy any additional products you can use lower level inputs for some devices. For example if you have a DVD player that has component cables you can use that instead of HDMI because DVDs are not High-Def. That would free up another HDMI input. If that is not enough then you can use a S-Video or composite video connection for standard definition products. Nowadays more and more products use High Definition, but some technologies are still not in HD, such as DVD players, older video game consoles such as the original Xbox or the Wii, tape players and VCRs, etc. Some wires are touted as higher quality than others and some special types of HDMI cables even have gold connectors and/or gold wiring inside of the cable. This theoretically produces a better signal, but it will not make a noticable difference in how your home theater looks or sounds. The reason this is, is because HDMI cables are digital so the audio and video signal is made up of a bunch of 0's and 1's sent in a block or square type of waveform, while analog cables like component or composite have a rounded waveform that is much more easily susceptible to noise and interference. The only difference that you should worry about in digital cables such as HDMI cables is extremely discounted cables bought from super cheap vendors such as eBay or at swap meets. Sometimes these cables do not make proper connections to each of the small wires inside so the signal is not sent properly. If you buy a properly made cable, even if it is not a name brand, it will most likely be fine for your home theater as all digital wires produce identical signals so you don't need to worry about buying an inferior cable.
Audio Connectors: There are also a slew of different connectors for audio signals, however now that HDMI has come on the scene many of these connectors are less prevalent but some pieces of equipment still use them. Also there are different types of wires and connections that are used to connect speakers to the receiver or amplifiers. The topic of audio connectors and cables is covered in another article.