How to Connect Speakers Using Speaker Wire

This article explains how to match up terminals and wiring to connect amplifiers and receivers properly.

Speaker Terminals

Most stereo receivers, amplifiers, and standard speakers (i.e., ones that are able to receive signals through speaker wire connections) feature terminals on the back for connecting speaker wires. These terminals are either the spring clip or binding post type.

These terminals are also almost always color-coded for easy identification: The positive terminal (+) is typically red, while the negative terminal (-) is typically black. Note that some speakers are bi-wire capable, which means the red and black terminals come in pairs for a total of four connections.

Speaker Wire

Basic speaker wire—not the RCA or Optical/TOSLINK kind—has only two parts to deal with on each end, a positive (+) and a negative (-). Simple, but there is still a 50-50 chance of getting these connections wrong if you're not careful. Obviously, this is something that is best avoided, because swapping the positive and negative signals can seriously affect system performance. It's worth the time to double-check that these wires are correctly connected before powering up and testing the speakers.

While the terminals on the back of stereo equipment tend to be easily identified, the same cannot be said for speaker wires. This is often where confusion can occur, because the labeling isn't always obvious.

If a speaker wire doesn't have a two-tone color scheme, look for a single stripe or dashed lines (these usually indicate the positive end) along one of the sides. If your wire has light-colored insulation, this stripe or dash may be dark. If the insulation is a dark color, the stripe or dash is more likely to be white.

If the speaker wire is clear or translucent, check for printed markings. You should see either (+) or (-) symbols (and sometimes text) to indicate polarity. If this labeling is difficult to read or identify, use tape to label the ends after you know which is which for quicker identification later. If you're ever unsure and need to double-check (especially if you have a jumble of wires), you can quickly test the speaker wire connection by using a basic AA or AAA battery.

Types of Connectors

Speaker wires are most commonly found as bare, meaning that you would use a wire stripper to expose the strands at the ends. It's good to twist the bare wire strands tightly so that they stay together as a neat single twisted wire, no matter if your equipment uses spring clips or binding posts.

You can also find speaker wire with its own connectors, which can facilitate connections as well as help quickly identify polarity if they're color-coded. Moreover, you can install your own connectors if you don't like to fumble around with bare wires. They can be purchased separately to upgrade the tips of your speaker cables.

Pin connectors are used only with spring clip terminals. These pins are firm and easy to insert.

Banana plug and spade connectors are used only with binding posts. The banana plug inserts straight into the connector hole, while the spade connector stays secured in place once you tighten down the post. 

Connecting Receivers or Amplifiers

Wires must be connected correctly on both the receiver or amplifier and speakers. The positive speaker terminal (red) on the receiver or amplifier must be connected to the positive terminal on the speakers, and the same applies to the negative terminals on all the equipment. Technically, the color or labeling of the wires doesn't matter as long as all the terminals match up. However, it's usually best to follow the indicators in order to avoid potential confusion later.

When done properly, speakers are said to be "in phase," which means both speakers are operating the same way. If one of these connections ends up reversed (i.e., positive to negative instead of positive to positive), then the speakers are considered "out of phase." This situation can cause serious sound quality problems. It may not damage any components, but you will most likely hear the difference in output. Examples are:

• Very thin, lean-sounding bass, poor subwoofer performance, or both
• No discernable center image
• A general sense that the system just doesn't sound right

Of course, other issues can create similar sound problems, but incorrect speaker phase is one of the most common mistakes made when setting up a stereo system. This can be easily overlooked, especially if you're dealing with a cluster of audio and video cables.

So, take your time to make sure that all speakers are in-phase: positive-to-positive (red-to-red) and negative-to-negative (black-to-black).