How to Connect 2 Speakers to 1 Amplifier

In this article we look at how and when to connect 2 speakers in parallel or series. Both the theory and practical points on how to connect 2 speakers are discussed. Connecting 2 speakers in parallel or series to your amplifier is useful when:

  • you don’t need to turn each speaker on or off individually, or
  • you don’t need to have separate volume controls for each speaker.

If you need to turn each speaker on or off individually or have separate volume controls, you may need a speaker selector switch. In this case you should read the articles on connecting multiple speakers, wiring 4 speakers, and/or my summary of speaker selector switches.

Many people get confused when we talk about a stereo amplifier. A stereo amp simply has two amplifiers built into the one box. We are not talking about connecting two speakers to a stereo amp, as that simply involves connecting one speconenct 2 speakers to stereoaker to each amplifier (left and right). There are many cases when you want to connect four speakers to a stereo amp, that is, to connect 2 speakers to each amplifier – or four speakers in total. For the rest of this article, when we talk about an amplifier, we are talking about either the left or right amplifier only.

You may want to connect 2 speakers to one amplifier without individual switching or volume controls if you:

  • have a large living area with four ceiling speakers, or
  • want to cover a large backyard with four speakers, or
  • have any situation where two speakers are not enough.

The are two basic ways of connecting two speakers together – either in series or parallel.

Should 2 speakers be connected in Series or Parallel?

Whether 2 speakers connected to one amplifier should be in series or parallel mostly depends on the impedance of the speakers.

The impedance of the speakers should be written on the back of the speaker Connect 2 speakers 8 ohmsor speaker box. The impedance of a speaker is normally 4 ohms, 6 ohms or 8 ohms. If it isn’t written on the back of the speaker, check any paper work that might have come with the speaker, or look up the specifications on the web. The Ω symbol is often used instead of writing “ohms”.

If both speakers are 8 ohms or more, then the speakers can normally be wired in parallel.

If the speakers are less than 8 ohms, then to be safe, you should wire them in series.

Connect 2 Speakers in Parallel

To calculate the total load impedance of speakers in parallel, see my Speakers in Parallel Calculator.

If both speakers are 8 ohms or more, then it is normally safe to connect them in parallel. This is because two 8 ohm speakers in parallel makes the total load impedance 4 ohms. Most HiFi amps are designed to have a total load impedance of 4 ohms or higher, but not lower than 4 ohms. If your amp is not specified for 4 ohms (some are 6 ohms or 8 ohms minimum), then you should consider wiring your two speakers in series.

This diagram helps show why speakers connected this way are called “in parallel”

Connect 2 speakers in parallel

They are known as being in parallel because, well, they are wired in parallel. Admittedly, I’ve drawn them so they look like being in parallel. However, in practice, we wouldn’t use so many cables and connections. For practical ways of connecting 2 speakers in parallel, see the table below.

If your amplifier has an A and B speaker selector, you can use this for a simple way of connecting two sets of speakers in parallel.

Connect 2 Speakers in Series

To calculate the total load impedance of speakers in series, simply add the impedances together

If both speakers are less than 8 ohms, or the amplifier requires a total load impedance greater than 4 ohms, then it is best to connect the speakers in series. This is because two 4 ohm speakers in series makes the total load impedance 8 ohms. Two 6 ohm speakers in series makes the total load impedance 12 ohms. Most amps work fine with a load impedance of 6-16 ohms.

This diagram helps show why speakers connected this way are call “in series”

Connect 2 speakers in series

As you can see, the two speakers are in “series” with the each other.

How to Connect 2 speakers in Parallel and Series

Below is a table showing how to wire up two speakers in parallel and series for common scenarios. Keep in mind these diagrams are for one amp only (let’s say the left amp), you will need to duplicate this for the right amp also.

If you double click on a diagram you should see a slightly larger version for easier viewing.

Practical Ways to Connect 2 Speakers in Parallel and Series
When all cables are run back to the amplifier location
Connect 2 speakers in parallel
Parallel: Both speaker cables are connected directly to the amplifier
Connect 2 speakers in series
Series:Join two of the wires as shown separate to the connections on the amp.
When the second speaker needs to be connected off the first speaker
Connect 2 speakers in parallel
Parallel: Join the cables of the second speaker to the cables on the first speaker
Connect 2 speakers in series
Series: Cut one wire near the 2nd speaker, and connect the 2nd speaker "in series" with the cut wire.
When there is a (long) cable run to be split to go to both speakers
Connect 2 speakers in parallel
Parallel: Join the cables from both speakers to the cable from the amplifier
Connect 2 speakers in series
Series: Join the two speakers in series, then join this to the feed cable
When the cables from each speaker come back to a wall plate
Parallel: Simply join the terminal as shown
Parallel: Simply join the terminal as shown
Connect 2 speakers in series
Series: The series connection is made with one join

You may have noticed that no matter which scenario is used, all the parallel diagrams are technically wired the same as each other – if you doubt me, trace the connections with your fingers on any two of the parallel connection methods. You can do the same for the series connections below as they are also the same as each other.

Keep in mind that changing the total load impedance of an amplifier will increase or decrease the power output of the amplifier. Connecting in parallel normally increases the output power, while a series connection normally decreases the power output of an amplifier. See Multiple Speakers Change Amplifier Power for more details.

Also if the speakers each have a different impedance, then there will be different power levels available to each speaker. For more detail see How Multiple Speakers Share Power. 

Summary of Connecting 2 speakers

There are only really two ways to connect 2 speakers to one amplifier – either in parallel or series.

If each speaker has an impedance of 8 ohms or more, then you can generally connect them in parallel.download article

If each speaker has an impedance below 8 ohms, you should wire them in series.

If you need to switch each set of speakers on or off, or you want separate volume controls, see my articles on connecting multiple speakers, wiring 4 speakers and/or my speaker selector switch summary

If you still have a question on how to wire two speakers, leave a question below so we can all learn about other situations.

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148 COMMENTS

  1. Hey Geoff,
    Just wanted to let you know how helpful you’ve been. I recently bought some speakers and was having trouble understanding the correct ways to wire them. I came to your website and was blown away by how helpful you were. Keep up the good work!

  2. Me & Dolby Atmos

    Our home cinema and our living room are one in the same room and in fully refurbishing the room in the past year so much of the speaker wiring was put into hidden trunking and any possible re-patches have had to be designed to be easily and discreetly achieved – hence a tiny patch box set up. The layout of my room and home cinema set up is such that I might wish on some occasions to push the side surround signals to my back speakers and vice versa for various reasons. Also I have wired in a spare pair of speaker cables so I could experiment with an alternative position for height speakers at some future point.

    In order to give me some flexibility in trying such things I have produced a tiny patch box set up. The other speakers in the 7.1 set up are all wired direct to the back amp terminal including a sub woofer. But the “side surround” and the “back/height” outputs of the Onkyo TN X646 are wired to a patch box.
    Using a set of “jump leads” of speaker wire, with banana plugs at each end, and using two adjacent patch boxes, I can switch between the various designations of the side surrounds, the backs, and the front heights and even use a spare set of leads with no speaker on the end of them currently so I could experiment with an alternative position for height speakers. All this can be easily done without having to change anything at the back of the Amp or relay any wiring.

    In the cinema exhibition industry I understand the top of the range Dolby Atmos compatible Amp for cinemas has 64 channels for up to 64 speakers around the walls and on the ceiling of an auditorium.

    In these early entry level Atmos Home Cinema Amps they just have one channel for a pair of height speakers. I think the reason the terminals on the these home Amps say – front height / back surround – is that the manufactures know many early domestic installations would not yet consider putting speakers into the ceiling and so have produced left and hand right front speakers for the domestic market that have integral “up facing to the ceiling” “height” speakers.
    There is just one channel of height information in the domestic 5.1 Atmos set up, and I don’t think it is that important if it is delivered by a set speakers in any one of various alternative positions. I don’t think people should just think of their pair of height speakers of being limited to just a front position. But it is important to note that most opinion agrees that the best spot for Atmos height sound to be appearing is to be as if it is coming down from the ceiling just in front of where the viewers are sitting.

    I ran my very first Atmos film “Everest” through my home cinema set up on Boxing Day. I had the wiring on the patch box configured for 7.1 Surround Sound but had 5.1 Atmos selected on the DVD and that what was going into the Amp.
    All I did was angle my two rear speakers, which are quite high up on a shelf behind the viewers, towards the ceiling, so that the sound would bounce back to as close as I could get to it be appearing as to be coming down from the ceiling just in front of where the viewers were sitting.

    The back speakers were acting as the height speakers with them bouncing the sound off the ceiling and the effect was great without having to change over any wiring whatsoever !! The sound of the rescue helicopter rotor blades appeared to be becoming from above us when we were inside the helicopter – very realistic.
    When we were inside a tent in a blizzard we could here the canvas of the tent flapping above us – again very realistic. During the mountain blizzard we could hear the wind and the thunder above us as well as from the side surrounds. It was the best surround sound experience I have enjoyed at home ever – it seemed to somehow almost incorporate the experience of 5.1 / 7.1 but there was a definite discernable height dimension when I believe I was supposed to be hearing a height dimension.

    Using the patch box system and a recommended “series connection” that Geoff has outlined to me – next time – I will engage the front height speakers too and that might increase the spread of the height effect more evenly and effectively more throughout the room – which is what I am hoping for.

    If you would like me to send you some illustrations of the simple patch box set up and the set of wiring patches – email me at: mark@creativeimage.org.uk

    C: A Recommended “series connection ”wiring patch for Dolby Atmos 5.1 with two pairs of speakers wired into the height channel one of which will be a pair of front heights. A “series connection ” of two pairs of speakers produces minimum strain on the Amp channel.

  3. I have 2 speakers, one is 6 ohms, the other is 8 ohms. So I should be connecting them in series as 14/2=7?

    Rms power of receiver is 100w 8ohms, Max power 170 watts 6ohms.

    • Hi Bryan,

      It looks like your amp can run with a load impedance no lower then 6 ohms.

      A 6 ohms speaker and a 8 ohm speaker in parallel does not give you a total impedance of 7 ohms (that simple formula is only for speakers with the same impedance). The total impedance is 3.4 ohms, which is too low for your amp when at full power.

      To be safe, I suggest wiring your two speakers in series (total impedance=14 ohms), or use a speaker selector switch.

      Hope this helps,
      Geoff

      • I was pretty confident that parallel was not going to be right, so thanks for reconfirming. I have them in series and the setup is working very well

  4. Dear Geoff

    I have an Onkyo TN X646 surround sound AV amplifier with Dolby Atmos Capability. The height channel is presumably driven by an individual amp within the bigger unit. I like the idea of attempting to drive a total of 4 height speakers from the two L & R and + and – outputs for the height channel. Currently all the speakers are 8 ohm speakers which are connected to a patch box via banana plugs that have the ability for another banana plug being plugged into its back. Can I plug in another two speakers into the back of the banana plugs for the existing two speakers which will I believe from your diagrams be a parallel arrangement? If i do this will it damage all the speakers or the amp ? I like the idea of attempting to drive a total of 4 height speakers from the two L & R and + and – outputs for the height channel as i think it will give a better effect given my room arrangement but I dont want to damage any component. Be grateful of your advice.

    • Hi Mark,

      I like your concept, but I’m not sure the amp will.

      Connecting two 8 ohms speakers in parallel as you suggest will give the height amp a total load impedance of 4 ohms. This is below the design minimum of 6 ohms for when your amp is at full power.

      So there are two ways forward:

      1) Don’t run the map at full power. The amp only needs to be a little under full power to cope with the slightly lower load impedance. I don’t recommend this, but many people do it. The amp has a protection circuit whereby it will turn off if it thinks it is overloaded, so that is the safeguard.

      2) You could run each pair of height speaker in series. This will give a total load impedance of 16 ohms. The amp will cope with this, but will not quite deliver its full available power. However this can be balanced out in the setting up of the levels – if you can hear any level difference.

      hope this helps

      Geoff

    • Mark, I am interested to hear how this worked out for you as I have the exact receiver (TX NR646) and I am interested in doing the same thing. I am going to be purchasing a pair of Tower speakers. Currently I have all in ceiling speakers (7 total). I want to connect the new Tower speakers directly to left and right channels of receiver which in turn will leave me with the two current ( L/ R ) in ceiling speakers not connected to anything. I want to then connect these in series to either the front height or surround back channel.

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