Speakers in Parallel Calculator

Simple Calculation for Speakers in Parallel

If all the speakers in parallel have the same impedance, then the calculation is easy. Simply divide the impedance by the number of speakers in parallel.

Example 1: Four 8 ohm speakers in parallel: 8 divided by 4 = 2 ohms.

Example 2: Two 4 ohms speakers in parallel: 4 divided by 2 = 2 ohms.

Not so Simple Calculations for Speakers in Parallel

For calculations involving speakers in parallel with different impedance, the following formula is required (it can be used with speakers of similar impedances too).

\large{R_{Total}}=\frac{1}{\frac{1}{R_1}+\frac{1}{R_2}+...}speakers in parallel calculator

If you have a calculator with 1/x button then this calculation is not too difficult. If you don’t have that function on your calculator, or if you don’t like formulas, check out the calculators below.

Simple Calculator for Speakers in Parallel

Below is a separate calculator for 2, 3 and 4 speakers wired in parallel. Following these simple calculators is another calculator which can be used for more complex series/parallel configurations.

Simply type the impedance of each speaker into the white boxes of the appropriate calculator. The total impedance for those speakers connected in parallel will be calculated.

Also for each speaker is a calculated percentage. The shows how the power output of the amplifier is shared between the speakers. Power sharing is a consideration when using speakers with different impedance. See How Multiple Speakers Share Power for further details.

 

These calculators will help you understand the total speaker load on your HiFi amplifier. For a better understanding of this and what to do about it, read the articles How do I Connect Multiple Speakers to my HiFi Amplifier and How to wire four HiFi speakers or How to connect 2 speakers to one amplifier or watch the video in the article Understanding Speaker Impedance.

Calculator for Series/Parallel Speakers

This calculator can be used for a series/parallel configuration or for two speakers in parallel. It goes a step further than the calculators above and allows you to enter the maximum power output of your amplifier for the calculated total load impedance. The maximum power through each speaker is then calculated. Also the difference in power between the highest power and the lowest power in the speakers is given as a ratio and in decibels.

 

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82 COMMENTS

  1. Hi Geoff!

    I have a amplifier and the lowest impedance rate of my amp is 2 ohms per channel

    And I have 12 speakers of 8 ohm each and I need to connect 6 speakers on each channel

    So my question is:
    How can I wire up 6 speaker of 8 ohm each to get a total of 2 ohms load

    Thanks!!

    • Hi Isaak,

      It is not possible to arrange six 8 ohms speakers to give you a total load impedance of 2 ohms.

      However 2 ohms is lowest the amp will work with, but it will also work with any impedance above 2 ohms, albeit with a sightly lower maximum output power.

      For example, if you connect 3 speakers in parallel, that gives you an impedance of 2.67 ohms. If you connect the other 3 speakers in parallel also, and then join both sets together in series, the total load impedance on the amp would be 5.3 ohms. The amp should work quite well with this load.

      Keep in mind that no matter how you connect them, the total power produced by the amp will be shared by the speakers. So if the amp can deliver say 1200 watts into 5 ohms, the each speaker will be driven by 200 watts (1200/6).

      hope this helps

      Geoff

  2. Hi Geoff ,

    I have an amplifier Yamaha rx-v365 ( Built-in 5-channel power amplifier ,(1 kHz, 0.9% THD, 6 Ω) ,Front: 100 ,W/ch , Center: 100 W , Surround: 100 W/ch ) and i want to connect 3 speakers eatch side of the front ( 1 – 80w – 8 Ohms , 2 – 100w 8 ohms , 3 – 100w 8 Ohms ) , How should i connect ? Parallel or Series , to not burst with any of the speakers or amplifier ? Thank you for your patience .

    • Hi Hugo,

      It is not simple to connect 3 sets of 8 ohm speakers. If you connect them in parallel, the total load impedance will be 2.6 ohms which is too low for the amp. If you connect them in series, the amp will be happier, but it will not produce as much power as it can. If you connect two in series and then in parallel with the third, then the sound level will not be even across the speakers.

      So using a speaker selector switch may be a better solution,

      Whatever method, the power from the amplifier will be split when all three speakers are being used at the same time. If each set of speakers are in a different room. then having a speaker selector switch will turn off the ones you don’t need. If all speakers are in the same room, it will not be louder than using one set of speakers.

      Geoff

  3. Designing Speaker System (Advice Needed)

    If I have a 700 Watt Stereo Power Amplifier (350 Watts Per Channel). I wish to wire a total of 8 speakers (4 Woofers each at 8 Ohms going to an inductor crossover & 4 Midrange Speakers each at 8 Ohms going through a 400 Volt Capacitor crossover) all together within one single speaker cabinet. How should I wire/configure this without overloading my power amplifier?

    1. Woofer: Out of the four woofers (each 8 ohms) – can I safely wire each “pair” of woofers in series going to the amplifier; which will give me 4 ohms?

    and in addition to the above within one single speaker cabinet; can I also wire the following:

    1. Midrange: Out of the four midranges (each 8 ohms) – can I safely wire each “pair” of midranges in series going to the amplifier; also, which will give me 4 ohms? NOTE: Please keep in mind that ALL of the midrange speakers are going to 400 Volt Film Capacitor …..does this effect impedance/ohmages?

    Now with everything as outlined above give me a total combined ohmage of 4 Ohms or 2 Ohms?

    *********************

    My second option would be to connect all of the four 8 ohm Woofers in series together and all of the four 8 ohm Midranges together going together into one amplifier terminal which will give me a total speaker ohmage of 16 ohms?

    *************************

    So what is my best solution for this speaker configuration without overloading my amplifier?

    Thanks everyone for your assistance.

    • Hi AJ,

      Unfortunately I’m a not a speaker designer, so I may not be a lot of help.

      I can though comment on your calculations. You talk about wiring each pair in series, then you use the parallel calculation. That is to say, two 8 ohms speakers in series will give a total impedance of 16 ohms, not 4 ohms.

      Then two lots of 16 ohms in parallel will give you 8 ohms in total.

      However there is then the cross over to consider, as you say. This is where I’m out of my area of knowledge. I would think that as impedance is frequency dependent, then the frequencies going to the woofers are only going to see the impedance of the woofer, and the frequencies going to the mids are are only going to see the impedance of the mids. But what happens in the cross over area will be the tricky bit, as the crossover is not a on/off type of cross over, but rather a gradual crossover, meaning some frequencies will see both speakers, or part therefore. This is where speaker designers earn their money, and they have the test gear to verify it all.

      Sorry I can’t help any more.

      Geoff

  4. Hi Geoff, I am looking for amp specifications to drive 6 8ohm speakers in a single outdoor room. The speakers are 150w RMS. Been through way too many articles and getting confused. Wiring 3 in parallel gets me to 2.67 ohm, but that seems pretty low. Wiring in series gets me to 24 ohm…is that just too high? Advice welcomed.

    • Hi Pete,

      As you have found, it is not easy to wire three speakers in series/parallel and get even power through each one.

      I think the best way forward would be to wire all three in parallel, which would give you a load impedance of 2.7 ohms for each channel (as you say). Then use an amp which will work into 2 ohms. Something like the Crown XLS1000 will deliver 550 watts into 2 ohms with both channels working. They are reasonably priced too.

      Does this help?

      Geoff

  5. I have an Episode 500 LCR speaker manufacturered by Snap AV

    Link below ….

    https://www.snapav.com/shop/en/snapav/episode-reg%3B-500-series-thin-design-3-channel-passive-soundbar-(each)

    It is a 6 ohm speaker.

    How can I rewire it so that all 3 channels operate as one ?

    I’ve tried wiring it in series , doing it this way it sounds beautifully but it presents a 2 ohm load to the amplifier.

    I’d like to rewire it so it works as a single 6 ohm speaker .

    Currently my amplifier goes into safe mode and shuts down at high volume.

    • Hi Kevin,

      Thanks for the link, saves me some time and effort.

      It seems you actually wired all three in parallel to get your 2 ohm total impedance, and hence the amp not liking that and turning off to protect itself.

      It is not easy to wire 3 sets of 6 ohm speakers in any configuration to give a reasonable total impedance and a level power sharing between them. My best attempt is to forget the center channel, and wire the left and right in series. This will give a total load impedance of 12 ohms, which the amp should cope with nicely. While this will lower the maximum power from the amp, it wont be overly noticeable. Both left and right will be same level and all common sound will appear to come from the center.

      let me know how it goes,

      Geoff

  6. Hi Geoff. Thanks for your page, it is very helpful. But alas.. I am still a little confused.

    I already have 2 (50wrms 4ohms)transducers wired to my game chair in stereo(1 on each channel). I am thinking of adding either 2, or 4 more 20wrms 8ohms smaller transducers. (These smaller ones also come in 20wrms 16ohms). I am trying to figure out if I can power all of them with one amp??

    Option 1) Add 2 smaller transducers:
    Left: 50wrms 4ohms + 20wrms 8ohms(or 16ohms)
    Right 50wrms 4ohms + 20wrms 8ohms(or 16ohms)

    Option 2) Add 4 smaller transducers:
    Left: 50wrms 4ohms + 20wrms 8ohms(or 16ohms) + 20wrms 8ohms(or 16ohms)
    Right 50wrms 4ohms + 20wrms 8ohms(or 16ohms) + 20wrms 8ohms(or 16ohms)

    When I use your Parallel calculator I get 2 ohms per channel, which seems really low for a amp.
    When I use your Series-Parallel calculator I get very high impedance and the wrong watts for the small and larger transducers.

    So, I am wondering what I am doing wrong. Or if I need to just power the small and large transducers with separate amps? Thanks!

    • Hi Andy,

      I think the only thing you are doing wrong is thinking you will get more power when adding extra transducers. If you have a 50 watt amp, then it will only produce 50 watts. Adding extra transducers (or speakers) will mean that 50 watts is shared by all the transducers.

      As you have seen, if you connect all three in parallel the impedance is too low for the amp. If the connect them in series, the total impedance is higher (not two high for most amps, but it will reduce the maximum power output form the amp).

      You could connect the two 8 ohms in parallel (a total impedance of 4 ohms) and then connect these in series with the 4 ohm, which would give you a total impedance of 8 ohms. The 4 ohm would take 50% of the power the two 8 ohms will take 25% each.

      Or you could connect it this way with a 100 watt amp. By increasing the power available each transducer you will get more power, but the ratios will still be the same.

      Certainly the best way to increase the power would be to use a second amp. If you connected both 8 ohm transducers in parallel (4 ohms total load impedance) to a 100 watt amp, then all three would get the same power (50 watts each).

      Geoff

      • Thank you very much for your reply Geoff! Since I am trying to get the correct wattage to each transducer (50, 20, and 20 wrms) I was thinking a 250 watt 4ohm amp should work using your Parallel / Series design. (250w x .707 = 176wrms, which is 2x88wrms) Just so I know that I understand what suggested, here is a diagram that I drew up for the design. Can you please take a look and see if I got it right? I really do appriciate you taking the time to help me. Thanks, Andy

        http://imgur.com/a/aoV16

        This design makes sense to me. But it seems you would still recommend a 2nd amp. I am open to that idea. Just thought one amp could do it all and would be just as good assuming it had the correct wattage and ohms needed.

        • Hi Andrew,

          I agree your idea will work. The impedance is taken care of and the power is good too.

          My only comment is that if the amp is 250 watt peak into 4 ohms, it is probably a lot less into 8 ohm, so you may want to check out how much lower it will be. Also check if the 250 peak watts is total or per channel. Either way, the 4 ohm will take 50% of the amp’s output and the two 8 ohm speakers will take 25% each, will be close to the distribution you are after.

          Well done.

          Geoff

  7. hi sir
    i have a onkyo 175W/ch @ 6ohms and i want to connect 2 speakers each on surround LR and Atmos LR.and i have wharfedale speakers @6Ohms each .please advice and if we connect 2 speakers on each channel is the 175W/Ch divided to 2 speakers ? please advice on what impedance i should use and in parallel or series connection it should be.

    thank you

    • Hi Jeemon,

      As you can tell from the calculator, running 2 lots of 6 ohms speakers in parallel will give a total load impedance of 3 ohms, which is double what the amp is designed for. Therefore wiring them in parallel is not wise.

      However you can wire them in series. The total impedance will be 12 ohms – your amp will like this better. While the power will be slightly less, I doubt this will be a problem.

      hope this helps
      Geoff

  8. Hello Geoff,

    My question is car audio related. What would be the best way to wire 2 subs with different impedances and how much power would I potentially be getting to each sub? I have a 2 channel amp that has a rated output of 1500w @1ohm stable. Both subs are 400w RMS and dual voice coil. 1 sub is 4 ohm and the other is 2. Bought the 2nd sub at a swap meet already wired up in a box and didn’t realize what the resistance was until I got to messing with the wiring. So now I’m stuck figuring out how to wire it best without overloading my amp or blowing my subs.

    Please help! I have a headache already from thinking through all the ways of wiring them lol.

    • Hi Victor,

      First up, car audio is not topic, but the principles should be the same.

      Wiring the 2 ohm and 4 ohm is parallel will give the amp a total load impedance of 1.3 ohms as you can see from the calculator above. While the amp will cope with this, the 2 ohm speaker will take twice the power as the 4 ohm speaker. So it will sound a bit louder (3dB).

      Is it possible to wire the 2 ohms as a 4 ohm speaker? this is would make the power even across both subs. However it may decrease its power handling capability.

      Either way, don’t forget that no matter what speaker/amp combination you have, if you try hard enough you can damage them. If you hear any distortion, turn them down as distortion is the early warning sign of emanate damage.

      Sorry I can’t be more help

      Geoff

  9. […] Whether resistance goes up or down with multiple speakers depends entirely upon how you wire them. If you wire them in series, then the resistance the amp sees will increase. If you wire 3 speakers in series, for example, the total resistance will be R1+R2+R3. If you wire them in parallel, however, the resistance will decrease. The formula for resistance in parallel wiring is more complicated. In general, if you are talking about 2 identical speakers, then the resistance of the pair will be double if you wire them in series and will be half if you wire them in parallel. It is possible to combine wiring types, for example to drive 4 speakers from a single amp by creating two pairs of serially wired speakers and then wiring those 2 pairs in parallel. If you do this with 4 ohm speakers, then the load from 4 speakers would still be 4 ohms because you double the resistance of the serial pairs by putting them in series, and you half the resistance by wiring those pairs in parallel. The combo of series and parallel wiring is very frequently used for home theater seat shakers, where you often need to drive large number of shakers with a single subwoofer amp. You can usually find a wiring approach that will make the amp happy with multiple speakers. If you can't get the resistance exactly what you want, it is safest for the amp to err on the side of too much resistance rather than not enough. There is an online calculator here -> Speakers in Parallel Calculator – Geoff the Grey Geek […]

  10. I have an amplifier that handles 4 ohm speakers per channel. I want to hook up three 4 ohm speakers per channel. Is it better for the impedance to be higher for the amp to be happy. Three 4 ohm speakers in parallel is 1.3 ohms which is too low and three in series is 12 ohms. A series/parallel combination would be 6 ohms, which is slightly higher than the amplifier requires.

    • Hi Jay,

      Other than a tube amp, all amps will work into a higher load impedance, but they don’t like a lower load impedance.

      As you say, 1.3 ohms is way too low.

      Series parallel will work fine, but the one on its own will be louder than the two in parallel.

      All three in series will give a total load impedance of 12 ohms, as you say. This will not hurt the amp. It just means the amp won’t work as hard as if it had a 4 ohm load, so its maximum power output will not be as high, but it will be happy. And all the speakers will be at the same level.

      hope this helps.

      Geoff

  11. what is the best for sony DSX-A30 50wx4
    1-pioneer TS-A6969E 300W 40W NOM
    2- SONY XS-N6950 600W RATED POWER 85W 100RMS
    THX

    • Hi Ashraf,

      I don’t normally give advise on particular gear. It is like asking “what car should I buy?”.

      In general though, you should get the speaker that sounds best to you.

      Check the impedance is within the range of the amp – this normally means it needs to be above 4 ohms.

      For power, it is best to have the amp slightly more powerful than the speakers can cope with. But you should never run the speakers load enough that they distort. For normal listening levels in a home, I would think both the speakers you mention will sound loud enough.

      Which brings us back to which speaker sounds best to you for the type of music you normally listen too.

      Geoff

  12. This calculator is confusing me. If I have 2 speakers in series and one is 2 ohms and the other is 4 ohms and the amp is 200 watts. Why would the speaker with higher ohms get more power? That is what the calculator is telling me. Shouldn’t the speaker with lower ohms get more power?

    • Hi Jeremy,

      Good point, and you are correct that the speaker with lower impedance will draw more power, if they are wired in parallel. However if they are wired in series, then the higher impedance speaker will draw more power.

      In a series circuit, the current through both speakers is the same. As the formula for power is the current squared times the resistance, the speaker with the highest resistance will draw more power. For example, let say there is 5 amps going through both speakers. 25 x 2 ohms will draw 50 watts. 25 x 4 ohms will draw 100 watts.

      I used to think it was the other way around too, but I think that is because we regularly deal with parallel connections, but not series.

      hope this helps

      Geoff

  13. Hi Geoff,

    I have bought a Yamaha micro hi-fi system, the mcr-n560, with two speakers included. I have also bougth a second pair of speakers, the Yamaha ns-pb182, which is exactly the same speakers, obviously with the same specs, as the ones included. So my question is, after reading most of the related articles and understanding some of it, am I doing the right thing to series wire the speakers to the amp?

    SPECS

    Center unit:
    Total Harmonic Distortion(CD to Sp Out, 20 Hz-20 kHz) 0.05%
    Output Power/Channel (6 ohms, 1 kHz, 10% THD) 32 W + 32 W

    Speaker System:
    Woofer 12cm cone woofer
    Tweeter 3cm dome tweeter
    Input Power (Max/Nominal) 40 W / 110 W
    Frequency Response 60 Hz-40 kHz
    Sensitivity 83 dB/2.83 V/1 m
    Crossover Frequency 5 kHz
    Impedance 6 ohms

    Thank you in advance

    • Hi André,

      You are correct. As along as you don’t need to switch any one pair on/off, wiring them in series is the best for the amp. It does lower the power to the speakers but it does keep the amp happy. Certainly, wiring them in parallel would over load the amp.

      If you want individual control over each pair, then a speaker selector switch would be required.

      Hope this helps,

      Geoff

  14. Hi Geoff, after lots and lots of online searching, I found your guides to be the best at explaining the “ins and outs” of whole house speakers. Still, I have some questions regarding calculating impedance for 6, 8 Ohm dual input stereo speakers for background music, as well as when to use the selector switch protection circuit switch.

    My stereo receiver is capable of 100w per channel. It has an A/B switch rated 4-8 Ohm A or B, 8 Ohm A and B. My plan is to use B—with or without A turned on—to feed a 6 speaker selector switch (with a push button 2×10 ohm/15 watts per channel impedance protection). I am planning on using a single 8 Ohm, 40W nominal 100W max, dual input stereo speaker (one speaker with both L & R input driving one woofer, two tweeters). One speaker in each of the 6 rooms. Each room will have a wall mounted volume control.

    Questions
    1. If I am following your calcs, that’s (8 Ohm speaker x 1/6 power) x 6 speakers = 8 Ohms total Impedance. Or, 8 Ohm x 6 speakers = 32 Ohms, divided by 6 = 8 Ohms total Impedance, yes?
    2. As long as I use all single, 8 Ohm, dual input stereo speakers this should match the stereo’s 4-8 Ohm, or 8 Ohm limits, yes?
    3. If all 6 speakers are on, then the speaker selection switch impedance Protection Circuit should be Off, yes? Otherwise, it’s adding 10 Ohms to the 8 Ohm speaker load, 10 more than the receiver’s 8 Ohm max?

    Or, am I misunderstanding some basics here? That you in advance Geoff. And the voice in the video is not what I expected given your picture 🙂

    • Ha! I’m disappointed you don’t like my falsetto voice! However my wife’s voice is far more pleasant than mine.

      I think you have confused the power sharing with the impedance calculations. Six 8 ohm speakers in parallel will share the power with each getting 1/6 of the available power. However six 8 ohm speakers in parallel will have a total impedance of only 1.33 ohms – way below the 8 ohms your amp needs.

      That is why speaker switches with a series resistor are popular as they provide a minimum resistance in the load. However a 10 ohm 15 watt series resistor is a bit high in resistance and way too low in power handling capability for a 100 watt amp.

      You mention each room will have a wall mounted volume control. If you use impedance matching volume controls, you won’t need a speaker selector switch. If you use the x4 setting on each volume control, that will look after the impedance matching for you (similar to the impedance matching selector switch in the video).

      Please come back with follow up questions if you need further explanations,

      Geoff

  15. Hi Geoff

    Thank you for your insight and patience to share your knowledge with all of us!

    My question is: I have a 2 way amp (Cambridge 851W, 200 watts per channel into 8 ohms
    350 watts per channel into 4 ohms) and i would like to test it by connecting 4 speakers (2 left, 2 right, 8 ohms/spk). What would be the optimal method of doing so?

    Thank you

    • Hi Stelios,

      Two 8 ohm speakers in parallel is 4 ohms. As your amplifier is designed for a load impedance of 4 ohms or more, you can simply wire each pair in parallel.

      Geoff

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