To get sound out of a guitar/instrument speaker or home audio system, you must first connect the speaker(s) to an amplifier. Many guitar amplifiers and small stereos come with amplifiers pre-attached to speakers, so there is no need to connect those. However, most high-end guitar amplifiers have speakers sold separately, or allow you to connect to speakers in addition to the one that came with the amp. Similarly, most high-end home stereos require you to connect the speakers to the amplifier manually.
Connecting a Speaker to a Guitar Amp
Locate the speaker output jack on your guitar amp. Usually, this is a quarter-inch input hole, though some guitar amps also have speaker output jacks for Speakon cables or XLR cables. Most of the time, the speaker output jack is on the back of the amp.
Plug one end of your speaker cable (quarter-inch, Speakon, or XLR) into the speaker output jack on your amp.
Locate the input jack on the back of your speaker cabinet. Usually, the input jack requires the same kind of cable as the speaker output jack on the amp (quarter-inch, Speakon, or XLR).
Plug the other end of the speaker cable into the input jack on your speaker. The speaker now connects to the amplifier.
Plug your guitar (or other instrument) into the amp, and turn on the amp. Most amps power the speakers directly, so you likely will not need to turn on the speaker. With the volume all the way down on your guitar, play your guitar and gradually increase the volume on both the guitar and the amp until you hear sound coming from the speaker. Adjust volume levels as desired.
Connecting Speakers to a Home Audio Amplifier
Place the speakers in the general areas of the room where they will reside. Make sure you can access the back of each speaker during setup.
On the back of the stereo amp, plug the speaker cable into the appropriate speaker output jacks. For example, most stereo amplifiers have outputs for left and right speakers at a minimum. Plug one end of the speaker cable for the right speaker into the right speaker output jack on the back of the stereo amp. Do the same for the left speaker (and all other speakers, depending on your setup).
Some stereos have two holes for each output jack, usually color-coded in red and black. If so, the cable that came with your stereo will also have two parts of wiring on each end of the cable. An easy way to remember which part plugged into the red connector and which part went into the black connector is always plug the side of the cable with writing on it into the red connector.
Connect the other end of the cables to the back of each speaker. For example, find the cable you plugged into the right speaker output jack on the amplifier, and connect the other end to the back of the right speaker.
If your stereo cabling has two ends (red and black holes on the back of the speaker), plug the side of the cable that has writing on it into the red hole on the back of your speaker, and the other side into the black hole. Connect each speaker in the room appropriately.
Turn on the stereo and play music at a low volume. Gradually turn up the volume until you hear music from the speakers. Once you confirm music is coming from all connected speakers, place them into the position you want them in the room.
If you connect speakers to a home stereo system or a guitar amp, and no sound comes out of the speakers, verify that all connections are set up properly. If they are, try a different cable. You might have a bad cable, prohibiting the speaker from playing any sound.
For guitar amps and speakers, Speakon cables are generally higher quality than quarter-inch cables, but since Speakon cables are relatively new, not all amps and speakers will have Speakon cable jacks. If you do have one, use a Speakon cable, which you can buy from your local musical instrument store.
Always use the correct cable. A quarter-inch speaker cable is wired differently than a quarter-inch instrument cable (the cable you use to plug your guitar into your amp), but both cables look almost the same. If unsure which one you have, ask at your musical instrument store. They can sell you a quarter-inch speaker cable.