Most stereo subwoofers consist of a large box with a single driver or speaker. However, some high-end subwoofers use two individual drivers to distribute signals and produce balanced bass tones evenly in a larger dispersal pattern or area. Connecting and using a dual-driver subwoofer is essentially the same as using one with a single driver. The method you use to wire the subwoofer to your receiver depends on whether the dual-driver speaker system is an active or passive type.
Active vs. Passive
If the subwoofer you want to connect came as a package with the receiver, then it is probably a passive model. Passive subwoofers rely on the amplifier inside the receiver to provide sufficient bass levels during playback and usually work with a set of satellite speakers -- front or center channel speakers -- to create a surround-sound environment. Conversely, active subwoofers have an integrated amplifier and may or may not integrate with surround-sound speaker systems. While you may be able to connect external speakers to an active subwoofer, the amplifier inside the enclosure powers the bass drivers only. The terminals for external speakers offer only pass-through connections from the receiver's amplifier. While most active subs have a volume control, it attenuates only the bass sound of the woofers in the enclosure and not external speakers attached to it. If you have an older two-channel receiver -- one without surround sound -- an active subwoofer plays bass frequencies while passing on higher ones to two or more regular speakers.
Tools and Supplies
Regardless of whether the dual-driver subwoofer you want to connect is active or passive, the things you need to wire it are essentially the same. Some receivers may have screw terminals for the speaker wires that require a Phillips screwdriver. Other than that, though, the only things you need to wire the subwoofer to the receiver are some speaker wire and a pair of pliers or wire strippers. If using a sub that shipped with the receiver, it should include appropriate-gauge speaker wire for making the connections. If adding an active or aftermarket sub, though, you should choose a suitable gauge or wire. For receivers with a modest power output of 60 watts per channel or less or for short-distance wiring runs shorter than 10 feet, 16- or 18-gauge speaker wire should suffice. However, if you are using a high-powered receiver with more than 60 watts per channel or are planning to install the subwoofer more than 10 feet away from the receiver, you should use heavier 12- or 14-gauge speaker wire to prevent signal degradation and sound loss.
Connecting a Passive Sub
Connecting a passive subwoofer to a surround-sound receiver usually requires nothing more than plugging an RCA cable into the appropriately labeled ports or attaching speaker wires to the correct terminals. Most surround-sound receivers have ports or terminals labeled "Subwoofer" or "Subwoofer In." Likewise, a passive dual-drive subwoofer should have a port or terminal block labeled "Amplifier" or "Receiver." RCA cables make it easier to connect the sub, but they are usually found only on budget or lower-end receivers. Consequently, many receivers and passive subwoofers have screw or push terminals for connecting speaker wires. Before connecting the subwoofer, power off the receiver. Then match the wire polarity with that of the terminals. The solid-colored speaker wire is the negative one and connects to the "-" terminals on the sub and receiver. The lead with a thin stripe running down its length is the positive wire and connects to the "+" terminals. Use the wire strippers or pliers to expose about one-half inch of bare wire before making the connections.
Wiring an Active Subwoofer
While most modern A/V or surround-sound receivers include a dedicated port or terminal block for a subwoofer, many older two-channel models do not. Connecting an active sub is relatively simple but requires slightly more thought. When you connect an active subwoofer to a receiver, you are essentially adding a filter that directs bass sounds to the sub and redirects higher frequencies to the external speakers. Therefore, you must route all audio signals from the receiver to the sub. You do not connect your left and right channel loudspeakers to the receiver at all but rather to the active sub. Most active subs have two sets of wiring terminals: one for the right channel and one for the left. Connect speaker wires from the two terminals on the active sub to the right and left channels terminals on the back of the receiver. When connecting the wires, be sure to connect the solid-colored wire to the negative terminal and the wire with the stripe to the positive terminal.
Connecting Other Speakers
If you are connecting a passive dual-channel subwoofer, the A/V or surround-sound receiver should have clearly labeled ports for other satellite speakers including "Front," "Center" and "Rear." Because an active sub filters audio frequencies from a receiver, you must connect satellite or left and right channel speakers directly to the subwoofer enclosure. Most active subs for home receivers have only two sets of external speaker terminals: left and right. The left and right terminals on the active sub enable you to connect two loudspeakers just as you normally would with an older two-channel amplifier or receiver. A few active subwoofer models, though, are similar to those used with personal computers and may include terminals or ports for adding front, rear and center channel speakers. While these types of active subs allow you to add pseudo surround-sound capability to a two-channel receiver, the channel separation and depth is not nearly as defined as with true surround-sound receivers or speaker systems.
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