This weeks blog is brought to you in association with Home Depot who have helped produce this in-depth guide to audio cabling. It will tell you everything you need to know about choosing the right products for the best audio output for your devices.
Audio cables transmit sound signals between components in a home entertainment system. Selecting the right audio cables is an essential step in getting the most out of your equipment. Even with the most advanced home theatre gear and top-of-the-line speakers, you can’t get the full surround sound experience without the proper cables.
Audio cables fall into two basic categories. Interconnect audio cables transmit signals from an audio source, like a CD player or cable TV receiver box, to your A/V receiver or TV. Speaker cable, also known as speaker wire, transmits audio signals from an A/V receiver to separate speakers. This buying guide explains the available options for both types of cable, so you can feel confident you’re selecting the cables that best meet your needs.
Factors to Consider
- Audio Formats – Stereo, analog surround sound, digital surround sound
- Interconnect Cable – Analog cables, digital cables
- Speaker Cable – Gauge, cable type, connector type
Audio Formats
The key difference between different interconnect cable options is what kind of audio formats they can carry. Different audio formats have varying numbers of audio channels:
- Most CDs are stereo, which means there are two audio channels encoded on the disc.
- Most DVDs are encoded with digital surround sound, which has six or more separate audio channels.
Surround sound formats include a number designation, like 2.0 or 5.1:
- The first number indicates the audio channels that correspond to directional speakers positioned around a room. For example, the “5” indicates there are 5 speaker channels in that system.
- The “.1” designation indicates an additional low-frequency effects (LFE) channel for the heavy bass sound, typically produced by a subwoofer speaker.
To access a particular sound format, you need three components:
- An audio source, such as a DVD player or cable receiver, that generates a signal in that format.
- The appropriate speaker set-up. For mono and stereo sound, the two speakers on a stereo TV are sufficient. For any surround sound formats, you need an A/V receiver that can read the format and the correct number of connected speakers.
- Interconnect audio cables designed to transmit the format between the audio source and the A/V receiver or TV. To use a particular type of audio cable, you’ll need jacks for that cable design on your audio source and on your A/V receiver or TV.
Refer to the table below for an overview of the standard sound formats and recommended interconnect cables.
Interconnect Cables
There are two basic categories of interconnect audio cables:
- Analog audio cables transmit sound as a continually fluctuating electronic signal. Analog cable can’t handle the 6 audio channels in a digital 5.1 surround sound signal, and are more susceptible to interference, in the form of electromagnetic and radio frequency waves, than digital cables.
- Digital audio cables transmit sound signals as a series of 1s and 0s, the language of computers. These cables can carry the six or more audio channels used in surround sound. This binary signal is also much less susceptible to interference and degradation than an analog signal.
It’s best to use digital audio cables if you have digital connections on your equipment, since these cables will deliver the optimal sound experience. However, analog cables will work as well, even with a digital TV or video source, such as a Blu-ray player.
Analog Interconnect Audio Cables
There are four standard analog interconnect audio cable designs and configurations used in home entertainment systems:
Coaxial RF cable – Also known as coax or F-type, coaxial RF is the most basic audio/visual cable. Coax can transmit a dual-channel stereo signal, along with an analog video signal. It’s used to carry signals between home theater components, like cable TV receivers and VCRs, but isn’t generally used with audio components, like CD players and tape decks.
Dual RCA cables – The standard analog audio option, RCA cables typically come in a pair, with a red plug for a right speaker channel and a white plug for a left speaker channel. Dual RCA cables are often combined with a composite video cable with a yellow plug.
| Multichannel RCA connections – Some home theater components and A/V receivers have six or more RCA connections, which allow you to use RCA cables to transmit more than two audio channels. This is a standard approach to transmitting the multichannel music formats DVD-Audio and Super Audio CD (SACD). Multichannel RCA connections can also handle surround sound signals, but it’s much more common to use digital audio cables instead. |
XLR cables – A mainstay of professional audio equipment, XLR cable connections are a stereo option found on some high-end A/V receivers. In home entertainment systems, XLR is typically used to connect receivers to pre-amplifiers and power amplifiers.
For optimal sound quality, look for analog cables made from high-quality materials, which typically do a better job conducting an audio signal and filtering out interference. Consider the material used in these three parts of the cable:
- Conductors – The wires inside the cable that actually carry the audio signal. For optimal results, choose cables with oxygen-free copper cable.
- Shielding – Material that filters electromagnetic and radio frequency interference that can degrade an audio signal. For optimal results, choose a cable with at least two shielding layers, such as a braided shield and a foil shield.
- Connectors – The part of the cable that plugs into a jack. For optimal results, choose a cable with gold-plated connectors. These will transmit the signal to the audio jack with minimal degradation
Digital Interconnect Audio Cables
There are three standard types of digital audio cable:
Coaxial digital cable – Not to be confused with coaxial RF cable, coaxial digital cable can carry up to six audio channels, making it a good choice for 5.1 digital surround sound. Coaxial digital jacks and plugs are the same size as analog RCA jacks and plugs, but the cable itself is very different. Typically, a coaxial digital jack will be colored orange, to distinguish it from the analog RCA jacks.
Optical cable – Like coaxial digital cable, optical cable, also called Toslink, can deliver 5.1 digital surround sound. Optical cables transmit the digital audio signal as pulses of light, which ensures a perfect signal. Coaxial digital cable and optical cable are roughly equivalent, and will deliver comparable results.
High-Definition Multimedia Interface (HDMI) cable – The best audio cable option available, HDMI can deliver eight separate audio channels, along with a video signal. HDMI is the only type of cable that can handle 6.1 and 7.1 surround sound formats encoded on some Blu-ray DVDs.
Since digital cables aren’t as susceptible to interference as analog cables, there is less variance in performance between different cable models.
Speaker Cable
Standard speaker cable consists of a pair of wire conductors encased in plastic insulation. When selecting speaker cable, elements to consider are gauge, cable type and connection type.
Gauge and Cable Type
Speaker cable is rated by gauge, or wire size, represented by an American Wire Gauge (AWG) number. Wire gauge is a measure of the diameter of the conducting wires inside the cord.
- Wires with a larger diameter can handle greater current than cords with a smaller diameter.
- Lower AWG numbers indicate a thicker wire and a higher current capacity, so the lower the number, the higher the cord’s capacity to deliver power.
Gauge requirements depend on the length of the speaker cable. Every extra foot of cable increases the electrical resistance, which degrades the signal the cable delivers to the speakers.
- For lengths less than 80 ft., use 16-gauge speaker cable or better.
- For lengths between 80–200 ft., use 14-gauge cable or better.
- For lengths greater than 200 ft., use 12-gauge cable or better.
If you need to run speaker cable behind walls or under the floor board, be sure to select cable rated for this purpose. Check the label for an Underwriters Laboratories® listing specifying the cable meets CL2 or CL3 certification requirements.
Connector Type
There are four common types of speaker wire connectors:
To determine your speaker cable connection options, first see what types of speaker cable terminals you have on your A/V receiver and speakers. There are two common terminal designs:
Spring clips use a simple clamping mechanism, designed to accept bare wire and pin connectors.
5-way binding posts use posts with screw-down connectors, designed to accept spade lugs, banana plugs, pin connectors and bare wire.
For the most secure connection, use a 5-way binding post combined with pin connectors, spade lugs or banana plugs. Stripped bare wire will work well too, but it may become frayed over time, especially when used with spring connectors.
I hope this has been helpful and if you have any doubt then go ahead and ask your friendly cable experts they’ll be happy to help.
