How to Bi-Wire and Bi-Amp Stereo Speakers

Spend less than 20 minutes to amplify speakers for improved sound

AN image of bi-wiring in home stereo speakers.

 Alexdi/Wikimedia CC 2.0

Those who are serious about audio tend to consider all the possible ways to adjust speakers in order to achieve that perfect sound. Small increments can surely add up, often transforming a great system into an excellent one. If you happen to have the right kind of hardware, you can opt to eek out extra performance by bi-wiring and/or bi-amplifying stereo speakers.

How to Bi-wire

There are some potential benefits to bi-wiring, although it's not guaranteed due to the subjectivity of sound. But before you start, you'll have to make sure the option even exists. Many newer, often high-end, speakers offer a bi-wiring/-amplifying connection. These models feature two pairs of binding posts on the back of each. So bi-wiring involves connecting two lengths of speaker wire to each speaker, one going to the woofer section and the other to the midrange/tweeter section.

Bi-wiring a speaker can be a relatively inexpensive way to improve overall sound quality. Ideally, one would run two identical lengths (and type and gauge) of two-conductor wire to each speaker. One wire handles the tweeter and the other the woofer for each speaker. Sets of bi-wire speaker cables can be purchased and used to the same effect. What bi-wiring can do is reduce the negative effects of the impedance differences between high and low frequencies traveling through a single wire. And by bi-wiring speakers with separate wires, it can also help reduce interaction between the two signals, thereby improving overall sound quality.

  1. Check for correct terminals. Not every speaker can be bi-wired. A speaker must have separate terminals (two pairs of binding posts) for the woofer and midrange/tweeter. Sometimes they are marked by the designation 'high' and 'low.' Sometimes they are not marked at all. If you're unsure, it's recommended to reference the owner's manual for further information before attempting to bi-wire any speakers.

  2. Remove the shorting bar. If you've been using your speakers normally (single wire), you might have noticed the little accessories that connect the positive and negative terminals. Once you take these out, the speakers are ready for bi-wiring. Be sure to remove them first before connecting the speaker wires to prevent possible damage to the speakers or amplifiers.

  3. Connect the wires. Plug in each pair of cables from the amplifier/receiver to the terminals on the speakers. Since the cables are identical, it doesn't matter which wire pair goes to which crossover side. If you happen to be using banana plugs, make sure that the connectors allow you to attach a wire from the side. Otherwise, you'll be left with ends going nowhere.

How to Bi-amplify

Now if you really want to go the extra mile, bi-amplifying speakers can offer another level of customization and control over sound quality. However, this can end up being a more expensive option, as it often involves having to purchase separate amplifiers. Some multi-channel receivers feature multiple amplification channels, thereby eliminating the need for buying new equipment. But the benefit of bi-amplifying speakers is that it allows the system to further isolate the frequency signals with separate amplification channels. This way, specific demands can be met without having to overwork the hardware and possibly lead to increased distortion.

For more appreciable results, some recommended to use an active crossover set-up rather than the passive crossover built into the speakers. The former method splits the signal into high and low frequencies before feeding them into separate amplifiers that lead to the speakers. The latter sends the full-range signal to the amplifiers first, which then forces the speakers to use internal filters to block the appropriate frequencies. One drawback to bi-amplifying (other than the added cost of amplifiers, crossover, and cables) is an increase of cable connections and system complexity. 

  1. Connect the high frequency first. Assuming that you've already bi-wired your speakers, disconnect the ends of cable that are plugged into the source. Connect these to the amplifier designated to handle all of the high frequencies.

  2. Connect the low frequency. Now repeat the above step, but with the cables and amplifier assigned to handle the low frequencies.

  3. Choose passive or active bi-amplifying. If you're going to go with passive bi-amplifying, connect both amplifiers to the source output. If active bi-amplifying is your goal, the two amplifiers will first connect to an active crossover unit. Then plug the active crossover into the source output.