Speaker cables carry audio from your device to the speaker
A speaker cable is the wire that runs from your audio source — a receiver, amplifier, soundbar, or computer — to your speaker. The cable itself is just two wires twisted or bundled together, each one carrying the same audio signal but in opposite directions so they cancel out interference. One wire is positive, one is negative. Getting them in the right holes matters, because reversed wires will make your speakers sound thin or cause them to work against each other if you have multiple speakers.
Most people connect speakers using one of three connector types: banana plugs (the small metal cylinders that screw into the speaker), spade connectors (flat U-shaped terminals), or bare wire (the copper strands twisted together). The cable itself does not care which type you use — the sound quality is the same. What matters is that both the positive and negative wires reach the speaker, and that you do not mix them up.
Key Takeaways
- Speaker cables have a positive wire and a negative wire; connecting them backwards will not damage anything but will make your speakers sound wrong.
- The three common connector types are banana plugs, spade connectors, and bare wire, and your amplifier or receiver will have one or more of these options.
- Red always marks positive and black always marks negative, whether on the cable itself, the speaker terminals, or the amplifier.
- If your cable does not have connectors attached, you can strip the insulation and twist the bare wires yourself, or buy pre-made cables with the connectors you need.
Identifying the positive and negative wires on your cable
Look at the cable itself first. If the cable has a stripe, text, or ribbing running down one side, that side is negative. If one wire is silver and one is copper-colored, copper is negative. If the cable is solid colored with no markings, you will need to look at the connectors or the amplifier to figure out which end is which.
At the amplifier or receiver end, the terminals are always color-coded: red is positive, black is negative. At the speaker end, the terminals are also marked — usually with a red dot or a plus sign for positive, and a black dot or a minus sign for negative. Match the marked end of the cable to the marked terminal. If you are using bare wire with no connectors, the wire that came from the red terminal on the amplifier goes into the red or plus terminal on the speaker.
Connecting with banana plugs
Banana plugs are the easiest connectors to use. They are small metal cylinders, usually about the size of a pencil eraser, that screw into the back of the speaker or amplifier. The plug itself has a single hole in the end.
Unscrew the terminal on the speaker or amplifier by turning it counterclockwise. Push the banana plug straight into the hole until it seats firmly. Screw the terminal back in clockwise until it is snug — do not force it. The plug will not fall out once the terminal is tightened. Repeat for the negative wire on the other terminal. If your amplifier has a switch that lets you choose between banana plugs and spade connectors, make sure it is set to banana plugs before you plug anything in.
Connecting with spade connectors
Spade connectors look like a flat U or a horseshoe. They slide onto a pin or post that sticks out from the speaker or amplifier terminal. The connector has two small metal tabs that grip the pin.
Loosen the terminal by turning it counterclockwise until the pin is exposed. Slide the spade connector onto the pin so the tabs grip it on both sides. Tighten the terminal clockwise until it is snug. The connector should not move or twist when you tug on the cable. If it does, loosen the terminal slightly and adjust the connector so it sits flat on the pin, then tighten again.
Connecting with bare wire
Bare wire means the cable ends with the copper strands exposed, with no connector attached. This is common on cheaper cables or when you have cut a cable to length. Strip about half an inch of the plastic insulation from each wire using a wire stripper or a utility knife. Twist the copper strands together so they form a tight bundle with no loose strands sticking out.
Loosen the terminal on the speaker or amplifier by turning it counterclockwise until the hole is wide enough to fit the twisted wire. Insert the wire into the hole and tighten the terminal clockwise until it is snug. Tug on the cable to make sure the wire does not pull out. If it does, loosen the terminal and push the wire in further, then tighten again. Bare wire connections are less reliable than plugs because the wire can work loose over time, so check them every few months.
What to do if your cable does not fit
If your amplifier has banana plug terminals but your cable has spade connectors, you have three options. First, check whether the amplifier has a switch that lets you change the terminal type — some models have both options built in. Second, buy a new cable with the connectors you need; a basic speaker cable with banana plugs costs between five and twenty dollars. Third, remove the old connectors and attach new ones yourself using a crimper tool, which costs ten to thirty dollars and requires a few minutes per connector.
If you are not sure which connector type your amplifier uses, look at the back panel or check the manual. The terminals will be clearly labeled as banana, spade, or bare wire. Do not try to force a connector that does not fit — you can damage the terminal or the connector.
Testing your connection
Once both wires are connected, turn on your amplifier or receiver and play some music or a test tone. You should hear sound from both speakers at roughly the same volume. If one speaker is much quieter than the other, or if the sound is thin or hollow, one of your cables may be reversed. Turn off the amplifier, swap the positive and negative wires on the quieter speaker, and try again.
If you still hear no sound, check that the cable is fully seated in both terminals. Tug gently on the cable at both ends to make sure nothing is loose. If the cable is loose at the amplifier end, the problem is usually there rather than at the speaker. Reseat the connector and tighten the terminal firmly.
Frequently Asked Questions
Can I use any speaker cable, or does the thickness matter?
Thicker cable carries current more efficiently over long distances, so if your speakers are more than fifty feet from your amplifier, thicker cable is better. For typical living room setups under thirty feet, standard cable works fine. The difference in sound quality between cheap and expensive cable of the same thickness is not measurable.
What happens if I connect the wires backwards?
Nothing breaks. Your speakers will still work, but the sound will be thin or hollow because the speakers are working against each other. Swap the wires back and the sound returns to normal. This is called being out of phase.
Do I need to turn off my amplifier before plugging in cables?
Yes. Always turn off the amplifier and unplug it from the wall before connecting or disconnecting speaker cables. This protects both the amplifier and the speakers from sudden electrical surges.
What if my speaker has only one terminal instead of two?
Some powered speakers have a single audio input jack instead of two speaker terminals. In that case, you do not need a speaker cable at all — you need an audio cable like an RCA cable or a 3.5mm cable. Check your speaker manual to see what type of input it has.
Can I splice two speaker cables together if one is too short?
You can, but it is not ideal. Strip the insulation from both cables, twist the matching wires together (positive to positive, negative to negative), and wrap the joint tightly with electrical tape. A better option is to buy a single longer cable, since splices can loosen over time and cause crackling or dropouts.