How To Wire Two Channels To One Speaker
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Wiring a single amp channel to one speaker is easy and has been the accepted norm with audio devices. However, if you have a single speaker with a two channel amp, you may want to wire two channels to one speaker.

This is possible, but did you know you can damage your amplifier if not properly done? You need to be careful because the correct setup will vary depending on the type of amplifier you are working with.

But don’t worry, in this article, we will show you how to correctly wire two amp channels to one speaker.

You can easily wire two channels to one speaker by using various methods such as bridging the amplifier, using a mono switch, or using a dual voice coil speaker. However, you should not connect the amplifier outputs in parallel as this may damage the amp.

Method 1: Can I Wire Left and Right Channels Together?

Firstly, please note that we do not recommend this method!

Having said that, one simple way to achieve a single speaker connection on two channels is by having both the left and right channels wired together or entangled.

By this, we mean the left channel is directly connected to the right channel to create a single output connection which is then wired to the speaker. This kind of wiring gives you a parallel connection-level output. 

wiring two amplifier channels to one speaker parallel

Because the connection will be a parallel one, it does not make sound quality any better. In fact, while doing this might not damage a good, modern amplifier, it can cause issues with older amps. You should really avoid this practice because both channels should be low impedance sources and so will be seen as shorts to each other which is a fault condition.

Besides, this kind of connection may deteriorate the quality of sound your speaker produces as the two channels will appear to oppose each other.

In fact, over time, the amplifier may get hotter and become more vulnerable to heat damage. 

This method of wiring is, therefore, possible but not recommended due to the likely consequences. In any case, if you decide to do it for some other reason, this is how it is normally done:

  1. Connect a wire on the positive terminal of channel 1 and another on the positive terminal of channel 2. Once you have the two wires connected, wound both end of the wires together to join them together into a single unit. Repeat the same procedure on the negative terminals of channels 1 and 2.  
  2. Once you have the two wires connecting channels 1 and 2 through the respective terminals, join the positive wire to the positive wire from the speaker, and the negative one to the negative wire from the speaker.

Method 2: Bridge The Amplifier

This is yet another method used by many to connect two channels to one speaker. Bridging an amplifier combines the channels into one channel with half the resistance – ohm (Ω).

The lower resistance means that the load (the speaker) will pull more current. This is a common practice to send a powerful mono signal to a subwoofer but can be used for regular speakers as well.

bridge amplifier to connect two channels to one speaker

It is however advisable to check that your amplifier can be bridged before attempting this process. Check the user manual, specifications on the amplifier itself, or get more information on the web.

Before you begin this DIY process, it is important to note a few things:

  • When an amplifier is bridged, its resistance load is cut by half. This makes it more likely to overheat.
  • You can only bridge amplifiers that claim to be able to bridge. This is because some amplifiers may have been bridged internally and further attempts to bridge it may result in internal damage.
  • For most amplifiers, you will find a small diagram near the channels or in the manual that indicates the terminals, you would use to bridge it. If you can’t find anything regarding this or how to bridge the amp, do not bridge the device.
  • Stereo amplifiers are built to be able to amplify both right and left. When this kind of amplifier is bridged, it becomes a mono amplifier and will be in a position to amplify from one channel only – left or right. 

Here is a quick overview of how you can connect your amp in a bridge arrangement:

  1. Now before we begin, let’s clearly identify the channel terminals. Check the rear of your two-channel amplifier and locate the terminals. Both channel one and channel two have positive and negative terminals. Channel 1 is labeled “A” for the positive terminal and “B” for the negative terminal while channel 2 is labeled “C” for the positive terminal and “D” for the negative terminal. 

This means that you will see 4 terminals: a positive (+) and a negative (-) for channel 1, and a positive (+) and a negative (-) for channel 2. Each of these terminals will be labeled as below:

  • Channel 1
    • “A” (positive)
    • “B” (negative)
  • Channel 2
    • “C” (positive)
    • “D” (negative)
  1. Grab the wires that come out of the speaker and fix the positive lead to the positive terminal for channel 1 otherwise marked with the letter “A”. Take the negative lead from the speaker and connect it to the negative terminal for channel 2 also marked with letter “D”. Make sure the wires are screwed properly. Many of these amps use binding post speaker wire connectors.
  2. You can also bridge 4 channel amplifiers in a similar way, except that the layout will be more complex:
  • Channel 1
    1. “A” (positive)
    2. “B” (negative)
  • Channel 2
    1. “C” (positive)
    2. “D” (negative)
  • Channel 3
    1. “E” (positive)
    2. “F” (negative)
  • Channel 4
    1. “G” (positive)
    2. “H” (negative)

The bridge arrangement gives you an advantage because it combines power from the two channels to deliver double the output to your speaker. As opposed to other methods, this method is, therefore, safe and produces better quality sound. 

Method 3: Use A Mono Switch

Another simple way to wire two channels to one speaker is through the MONO switch method. It is pretty much converting a multiple channel amplifier to a monoblock amplifier or sorts.

amplifier mono switch

In this way, you will design a high impedance input summing amplifier to add the two signals before the final power amplifier.

In other words, this is a form of connection where two channels are internally combined into a single output unit.

adding a mono swicth to amplifier to connect a single speaker to 2 channels

This method is very similar to the bridge arrangement and combines the L+R signal to both the speaker amplifiers and speakers simultaneously.

However, it is more permanent and usually done on the interior of the amplifier. Additionally, this removes the stereophonic effect and makes the signal seem flat and less dimensional.

How To Create A Mono Switch – DIY


Many old generation amplifiers were designed with a MONO switch. This kind of design allows you to safely wire a single speaker to two channels without damaging the amplifier. However, if you don’t have an old version amplifier, you can also attempt a DIY to make your own MONO switch in your stereo. 

Method 4: Use A Dual Voice Coil Speaker

In this method, we use a dual voice coil speaker with isolated coils. A dual coil speaker has two voice coils that allow a single speaker to output both stereo channels through one speaker.

In other words, you can get a stereo signal from a single speaker. This is a popular design for subwoofers.

dual voice coil speaker

Please note that connecting these speakers can be quite confusing and if don’t know how to properly wire a dual voice coil speaker, you can end up getting less sound and power output than you expect.

dual voice coil amplifier with 2 channel amp

There are many ways to connect dual coil speakers, but we recommend connecting the device in a parallel to parallel fashion:

  1. Use a speaker wire to connect both positive terminals of the speaker together.
  2. Use another speaker wire to connect both negative terminals of the speaker together.
  3. Connect the negative lead of the amplifier (from the negative terminal of the amp) to either negative terminals of the speaker.
  4. Connect the positive lead of the amplifier (from the positive terminal of the amp) to either positive terminals of the speaker.

Then the power is summed to acoustic power when in phase but cancels to zero when out of phase even though both amplifier channels might be working hard.

Why Wire Two Channels To One Speaker

If you are a sound engineer, an audio technician, DJ, a student, or an audio device user, trying a few connections between your speaker and the amplifier may just be something to do in your free time. Of course, it’s a great way to increase the overall power output to your speaker.

Trying a double channel connection on one speaker will therefore help you develop a better understanding of the sound dynamics of speakers and amplifiers that are commonly used at home or workplaces.

Final thoughts

We have just mentioned a few methods you can use to connect one speaker to the two channels of a two-channel amp. However, keep in mind that we do not recommend connecting the terminals in parallel. Remember, every amplifier channel is designed to accommodate a single speaker unit for the best performance.

It is therefore highly recommendable that you acquire two speakers for your two-channel amplifier. Of course, for greater output, you can use a mono switch or bridge the amp, but you need to be careful and follow the instructions exactly. Good luck!