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All About Audio

In our last article, we focused on the different types of video connections available to us for computer and home theater applications, and common video conversion problems and solutions. This article will aid in understanding the different types of audio connections, audio formats, and where they are used.

How do you know what audio connection to use?

There are so many different audio connections out there now; how do you know which one will be the best to use?

Generally speaking, the best audio connection to use would be whatever the common connection between the two devices is. For example: For home theater use, a single pair of audio RCAs (Red and White) is the most common analog audio connection, and Digital Coaxial is the most common digital audio connection.

With most home theater systems, the digital audio is going to provide a better experience than analog. However, not every device on the market has a digital audio option. Digital cables, whether digital coax or fiber optic (Toslink), pick up a lot less interference versus analog cables, especially over long runs.

For instance, when connecting a DVD Player with a fiber optic output to a TV with analog inputs over a distance of 50 ft the best option would be to run a 50 foot length of fiber optic from the DVD player, and then convert that fiber optic into analog audio to connect to the TV. This converter is called a Digital to Analog Converter (DAC). However, if you want something a little less elaborate, a single pair of audio RCAs (Red and White) will also work, but with a greater risk of interference. This risk can be minimized by using high quality properly constructed and shielded cables.

As the popularity of home theater systems booms, some companies are opting to combine high-end digital audio with digital video. HDMI is a new digital audio and video connection designed to compete with DVI. Not only is the connector a lot smaller than DVI and produces the same video quality, but it also transmits digital audio over the same cable. This makes it an ideal choice for installers. As a result, we are starting to see more televisions and cable boxes coming equipped with HDMI connectors that can transmit both video and audio.

What audio connectors are out there, and where can they be found?

The most common audio connections you'll find are:

3.5mm (also known as 1/8 inch or the small headphone size)

3.5mm (also known as 1/8 inch or the small headphone size) The 3.5mm connector can most commonly be found on: a walkman, MP3 player, and the sound card on a computer. Its compact size makes it an ideal stereo connection for smaller devices.

6.3mm (also known as 1/4 inch or the large headphone size)

6.3mm (also known as 1/4 inch or the large headphone size) The 1/4 inch connector is an older audio connector; it can most commonly be found on a TV or a receiver / surround sound amplifier. It is also used on home / karaoke microphones, electric guitar cables, and older headphones.

Digital Coaxial

Digital Coaxial Digital Coaxial cables can most commonly be found on: a CD player, DVD player, receiver / surround sound amplifier, satellite receiver, digital cable box, and an HDTV receiver.

Digital Fiber Optic

Digital Fiber Optic Digital Fiber Optic cables, often referred to as "Toslink" or "Digital Optical" cables, are generally found on the same devices as digital coaxial cables. They have the advantage of being less susceptible to electrical interference over longer distances.

Stereo RCA (Red + White)

Stereo RCA (Red + White) Stereo RCA can most commonly be found on: a VCR, TV / HDTV, CD player, DVD player, Cassette player, receiver / surround sound amplifier, satellite receiver, cable box, digital cable box, and an HDTV receiver.

XLR

XLR connector The XLR connector can mostly be found on a microphone, sound board, and a mixer.

Audio Oddities

How many different audio formats are out there?

Surround Sound Speaker Connections and Layout

Diagram 1:
 Surround Sound Speaker Wiring Diagram

Diagram 1 illustrates the connections between the speakers and a Receiver / Amp. All speakers require a positive and negative connection for them to work as you can see above. Primarily the subwoofer will connect using an RCA cable; the reason for this is that a powered subwoofer has an amplifier built into it, so the amplification will occur in the subwoofer itself. Since the amplification is occurring in the subwoofer, the non-amplified signal would be called a Line Level Signal (see glossary).

Glossary of Industry Terms