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Thankfully, hooking up audio and AV systems is much more straightforward than it used to be. For most people, home entertainment systems no longer consist of large racks of individual components hiding a rat’s nest of wires and connectors, and we’re better off for it. But there are still times you need to connect audio hardware devices, and if you need to source cables (cords), connectors, or adapters, knowing the specific names of each type is necessary. Let’s go over the ones you’re most likely to encounter. Automotive Connector Kit
Editor’s note: This post was updated on July 7, 2023, to account for changes in our house style and formatting standards.
Wired headphones connect to a playback device’s analog headphone socket using a jack plug. Suppose they’re standard stereo headphones with no microphone. In that case, it’s a three-terminal tip-ring-sleeve (TRS) connector, easily identified by the two insulating bands (usually black) on the barrel of the jack. These are commonly found in two sizes. The smaller size found on portable devices is referred to as a minijack, or by its diameter, 3.5mm. It’s sometimes called a 1/8-inch jack in the US, though that’s an approximation. The larger size of headphone jack you’ll find is commonly known as a 1/4 inch (or 6.3mm) jack plug. Adapters are easy to find to change one size jack plug to the other.
Wired headphones with a microphone built-in use a modified version of the same-sized minijack plug but with an additional electrical terminal (to carry the mic signal) in the form of an extra ring, making it a tip-ring-ring-sleeve (TRRS) connector, which has three insulating bands visible on the barrel.
Since smartphones have abandoned the headphone jack, you have three options. If you already have wired headphones you want to use; you’ll need a special adapter (a dongle) to connect to the phone’s system connector (a Lightning connector on iPhones or USB-C for basically everything else) and provide you with the analog 3.5mm headphone socket you need to plug in your headphones. These are also referred to as digital-to-analog converters (DACs).
If you want to stick with wired (for reasons) and don’t want to deal with dongles, you can get a set of wired USB headphones to plug directly into your phone. If you prefer to avoid dealing with dongles or wires, you can also go down the wireless, Bluetooth route.
You may have run into premium headphones with other jack sizes, different pin configurations (4.4mm Pentaconn), or larger XLR-type connectors. These are required to run your headphones in a balanced or differential drive configuration.
When the cable is removable, the plugs used at the headphone end vary quite a bit, and we won’t cover them all here. 3.5mm jacks with a twist-to-lock system are relatively common. You’ll also find 2.5mm TRS jack plugs on some headphones (Bose, for example), while others have 2.5mm TS jack inputs at the bottom of each ear cup for the wires to connect to (the Monoprice Monolith M1060, for example). Premium headphones can use mini XLR connectors; some use propriety connectors like Sennheiser‘s two-pin push-fit connector.
Many in-ear monitor (IEM) headphones employ micro-miniature coaxial (MMCX) connectors. As the name implies, this connection standard is small enough to fit into a pair of in-ear monitors easily. These are used mainly for better-engineered in-ear monitors, where having a replaceable cable means the headset doesn’t become trash if the cable fails. Plus, the connection itself locks into place and allows for 360 degrees of rotation, so not only does it make the cable easier to replace, but it also makes it harder to break in the first place.
Jack plugs are also used to connect audio signals at “line level” in several contexts. 3.5mm TRS minijacks are found at the ends of the standard auxiliary (“aux”) cable to connect your phone directly to a portable speaker or car stereo system. The larger 1/4-inch plugs are used in semi-professional applications to connect signals using TS plugs (unbalanced applications) or TRS plugs (balanced applications).
XLR connectors carry the tiny electrical signals produced by microphones and in other instances where signal integrity is essential — typically professional audio environments. Microphones have male outputs, and mic preamps have female input connectors on the front; hence, the standard XLR cable has a female on one end and a male on the other. The locking connectors are relatively large and heavy, explicitly designed for carrying balanced signals and wired using balanced (microphone) cable. This cable type is well suited to longer cable runs, as they have better shielding and noise rejection abilities.
RCA (or phono) connectors are smaller cinch-type connectors used in interconnects for connecting “line level” audio signals in consumer products. You’ll likely recognize the red and white color-coded stereo cables from their use in connecting older hifi system components or the yellow plugs that carry analog video signals to TVs from old DVD players, VCRs, or video game consoles. Since they can only carry unbalanced signals, they’re only suitable for relatively short-distance transmission of audio and video signals. They are still reasonably common, particularly for connecting record player turntables to phono input stages or connecting home theater subwoofers. They are also used for coaxial, digital audio connections (see the section later on).
Unlike a lot of connectors, the RCA name isn’t derived from a particular physical aspect of the connection. It’s named after the Radio Corporation of America, which developed and introduced the standard in the 1930s.
Unless you’re hooking up a PA system, the primary connector you’ll likely need to connect your speakers is the banana plug, shown above on the right. Many speakers have binding posts or terminal clamps that will accept the bare ends of the speaker wire. If that’s the case, connecting the positive terminal at the source (amplifier) to the corresponding terminal on your speaker is essential to keep everything in phase. Most speaker wire has an identifying mark on one of the conductors to help you keep track of what’s what. In some smaller powered speaker systems, the cable that connects the left and right speakers uses RCA (phono) connectors, as shown below.
Stereo interconnects, which usually have red and white (or red and black) labeled RCA connectors on the ends, are intended for low audio voltages (line level) with low current, and have a central insulated conductor surrounded by a shield (ground) for each channel (left and right).
Speaker cable, or speaker wire, consists of a pair of conductors surrounded by an insulating, flexible PVC or similar material that either has bare ends or banana plugs (see above) at the end. This cable should be specified to carry the power needed to drive loudspeakers to produce sound. Heavier gauge wire is required for higher power, and cables should always be kept as short as possible. As long as these basic requirements are met, there’s no point in spending a lot of money on cables, as this past experiment demonstrates.
Digital audio connections transfer signals between devices without converting them to analog and back again, which means the quality is preserved. Another bonus is that digital signals are less susceptible to sources of noise and interference, which makes cable quality even less of a concern than with analog.
Standard consumer-level wired stereo digital connections, often labeled “coax”(pronounced co-axe, not like the word coax), use the same RCA connectors we discussed previously, specifically with 75ohm coaxial cable. Home theater and AV systems are more likely to use high-definition multimedia interface (HDMI) cables, which also carry digital video signals. These allow eight or 32 audio channels (for HDMI version 2 and above) for surround systems, including Dolby ATMOS, and offer bidirectional capabilities in the form of HDMI ARC and eARC.
Optical cables (also called TOSLINK) carry digital audio between devices in much the same way as a wired coax connection, using light to represent the binary data instead of electrical voltage levels. These are preferred in most applications for stereo as they provide electrical isolation between devices, and they can also carry up to eight audio channels in multichannel applications.
High Voltage Connectors Automotive If you’re looking to transfer audio between devices, these are the most common ways, depending on the type and age of equipment you’re looking to connect. Hopefully, this has helped, and now whether you’re looking to listen to music wirelessly or hook up a state-of-the-art soundbar, you’ll know what you need to do it.