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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118 COMMENTS

  1. I have been googling for an answer and stumbled on your website. I have a McIntosh MC2205 200w amplifier with autoformers. I am using a Russound SDB-4.1 speaker selector, also with autoformers, connected to three pairs of 8ohm speakers.

    I don’t necessarily use all three pairs at one time but often do. Which tap in the amplifier should I connect the selector to? 2, 4 or 8?

    • Hi Shawn,

      I’m more technical rather than being an audiophile, so others may have a different opinion to me based on different criteria.

      So, technically speaking, I would probably set the multiplier links to x2 (the default). With all three sets of 8 ohm speakers connected in parallel the total speaker impedance would be 2.6 ohms. Then multiply this by 2, and the minimum load impedance the amp will see would be 5.43 ohms (when the switch volume controls at are full volume). So connecting to the amp at 4 ohms would probably be a good fit.

      Obviously, with less speakers connected, the load impedance will increase. You can play with all this on the third speaker switch simulator. Having a different load connected to the amplifier shouldn’t cause any harm, it just doesn’t give the best possible power transfer – which you don’t need at lower levels anyhow. So my reasoning is to set the switch and the amp for best power transfer when you want the most power (that is, with all speakers connected and all volume controls up full).

      hope this helps some

      Geoff

      • Geoff-
        Thanks so much. I missed that simulator when I was searching earlier. My speaker selector (sdb4.1) manual says the default multiplier is x4 so I think if I am using your simulator correctly I am safe using the 8 ohm tap. That is what I have been using these last two weeks.

        Thanks so much for your time.

  2. I have (2) 2ohm phoenix gold ti312d2 speakers and need to get them to a 1ohm load to run on my phoenix gold elite.5.? Did I buy the wrong speakers? My amp is only stable to 1ohm not .5ohm!

    • Hi Ryan,

      Let me start by saying I’m not a car audio person, so I don’t claim any expertise at all in this area. However the basic physics still hold.

      The amp looks a solid unit and will work into any load above 1 ohm. Obviously it produces more power at 1 ohm (1100 watts), but it will work fine at 2 ohms (700 watts) on the sub output.

      The Phoenix Gold subs look, their documentation is quite limited. Normally a dual coil sub will allow you to wire the two coils in series, giving you a 4 ohm sub. You could then wire the two subs in parallel and get a totals load of 2 ohms.

      To my mind this will work technically, but car audio people seems to have to get the most out of everything – but, as I said, I’m not a car audio person. Mind you, the difference in level between 700 watts and 1100 watts is less than 2dB – not much in reality.

      Sorry I can’t help more

      Geoff

  3. Hello Geoff,
    Working on Sundays?
    Here is what I have run across.
    I have 6 speakers all connected with a single lead (+ / -) running back to the head end.
    All the connections are behind the drywall some where cant see them at all.
    in testing i attached my tone generator to one of the 6 speakers and got the generated tone at each speaker through the toner.
    I have a 50 watt 8 ohm amplifier.
    do you know what needs to happen to get the proper impedance at the amplifier.

  4. Hi Geoff,

    Love the site!

    I have eight 8ohm speakers(250) I want to connect to an amp. The amp is rated 800@ 2ohms, 550@ 4ohms, and 325@ 2ohms. If not possible, what would be the correct speakers/watts to get for this amp. Also do each speaker get the same amount of watts or does the amp distribute the watts evenly the more speakers you connect. Your help would be great.

    • Hi Mike,

      I assume you have a stereo amp, and therefore only need to connect 4 speakers to each side.

      This being the case, you could connect all four in parallel. This will give a load impedance of 2 ohms for each amp. Which according to your comment the amp is designed for.

      The 800 watts from the amp will be distributed evenly across all four speakers, so each speaker will see 200 watts when the amp is at full power.

      hope this helps

      Geoff

  5. Hi Geoff. Great site you have. So my question is I have an amp that puts out 1500 watts Rms@ 1ohm. If I’m running it at 1.33 ohms how much rms power would you figure it puts out? Then same question for 1700 watts rms@1ohm running at 1.33 ohms. What would its rms power output?

    • Hi,

      I would hazard a guess by saying it would out just slightly less. But it would all depend on the design and build of the amp.

      I doubt you could discern the change in output.

      Geoff

  6. Hi Geoff

    Absolutely fantastic site you have. Great work!

    I appreciate this will probably sound a little strange but here goes.

    I have a Technics SU-V300 amplifier.
    It has A and B speaker selection.
    This I think has 27w per channel but I’m unsure if that’s per speaker channel when running in A and B mode or just with only A or B.
    Running A or B only it can do 4-16 ohm loading.
    Running A and B it can do 8-16 ohm loading.

    My speakers I have are 2 centre channel speakers.
    Focal CC700S and Focal CC700V.
    They are both 8ohm.

    My plan is to run the tweeters off 2 channels but this would be with the one from A and one from B both being a right signal.

    Then to run 2 woofers from each channel again one from A and one from B both being a left signal.

    Now these are not being ran as a centre speaker in home theatre at all. I’m splitting the signal up so strangely because I’m planning to remove the passive crossovers from the circuit and to make them active, I don’t have the correct active equipment as such but I do have a way I think may well work and before I buy some small chip amps I just need to test the validity of my theory. If it doesn’t work then I have a different idea to go down that will work but that means buying different amps hence this is just a trial.

    My issue is I can work out the ohm loading for the speakers in many different configurations I could do but due to trialling with this amp which I think is already parallel internally I’m unsure how or if that affects what the amp sees.

    So basically my left signal is doing the woofers.
    Right signal is doing the tweeters.
    Channel A would have 1 tweeter 8ohm on one output and two 8ohm woofers on the other output.

    Duplicated for channel B.

    What will the amp see per channel A/B and what is the best way to wire the 2 woofers per this amp. Also any idea on the wattages they would see.

    I understand I can use just one speaker per channel on speaker set A bit this as I said is an experiment into what is possible for my plans which is more about testing the set up from source to line in on the amp but I would run it as that until I buy the amps.

    Thanks so much I hope this makes some sense even if only a little.

    • Hi Simon,

      I think I understand what you are trying to do.

      First up, you are correct in that the A and B outputs are the same. They are in parallel and simply provide a convenient way to connect and switch two sets of speakers. So for calculation purposes they are in parallel.

      So, lets say you use the left channel for the tweeters. You would effectively have two 8 ohm speakers in parallel, giving a total load impedance of 4 ohms, which should be fine for the amp. Each tweeter will share the power from the amp 50/50.

      Now the right channel will have four 8 ohms speakers. Wiring them in parallel will give a total load impedance of 2 ohms, which the amp will not like at all. However if you wire the pair in each box in series (8+8=16 ohms), then the two boxes wired in parallel (one on A and one on B) will give a total load impedance of 8 ohms. Each speaker will get 25% of the power from the right channel.

      I’m not completely sure why you would want to do this, but it will work technically. However I think you will find the tweeters are much louder than the woofers. You can adjust this with the balance control, or your external processor when you go that way.

      Hope this helps

      Geoff

      • Many thanks Geoff.

        Yes it was the already parallel amp that made me think I had my calculation wrong which you confirmed and it would be as you say.

        I have various equipment doing nothing so I’m experimenting to learn about about ohms effects on wiring and active type designs and how much power I need to run the speakers. After I posted my question I had an even crazier idea.

        The full set up is like this and it’s a bit complicated haha
        iPhone as source outputting mono.
        Into pioneer DJM250 DJ mixer with left input on channel 1 and right input into channel 2, this gives me gain input on the split mono signal, 3 band EQ with infinite to +9db and HPF/LPF on each channel, channel 1 becomes LP, channel 2 becomes high pass, Independant volume control and master volume out.
        Then possibly go into a Marantz 7 band EQ.
        Then into a Promitheus TVC passive pre which gives me my 2 mono signal inputs into 4 mono outputs with attenuation volume control.
        Then from there the 2 left LP mono signals wired to L/R input of a Marantz NR1501 A/V receiver and use 4 channels of 50w @8ohm x4 per driver as I have 4 woofers to drive. Set it into multichannel stereo, have volume control and bass treble if needed.
        Then the 2 Right mono HP signal to the Technics L/R input with 27w @8ohm driving the tweeters with with volume control and tone if needed.

        It’s a fun project if nothing else.

  7. Hi Geoff,
    I am trying to wire 6- 8ohm speakers as efficiently as possible. They are all in my garage, and I have a Crown CDi 1000 amp (its 2 channel, 275W @ 8 ohms per channel). Speakers are handling 80 watts RMS. I used the series/parallel calculator and it gave me 45.8 watts power for each speaker. But it says if I wire them all in series/parallel the total load impedance for the amp is 12 ohms. Also total impedance for first 3 and last 3 speakers is 24 ohms. What does this mean? The amp can handle 2, 4, and 8 ohms, but I don’t think 12. Is wiring like this not a possibility in my situation?

    • Hi Trey,

      Your amp will run fine with a total load of 12 ohms, it just wont work as hard or be quite as loud as running into 4 or 8 ohms.

      However if you have six 8 ohm speakers, won’t you have just 3 speakers on each channel? If this is the case, then you could run each set of three in parallel. This will give each of the dual amps a load of 2.7 ohms. Since you amp will work into a load of 2 ohms or more, then this should be fine.

      hope this helps

      Geoff

  8. 2 6-ohm speakers
    2 unknown impedance speakers.
    Amp capacity is 6 ohms to 18 ohms

    What’s the safest? Wiring them in series or parallel?

    • Hi John,

      Running a speaker of any impedance in parallel with a 6 ohms speaker will result in a total impedance less than 6 ohms, so best not to run any other speakers in parallel. Wiring them in series will be safe for the amp.

      Geoff

  9. I am attempting to build a set of custom speakers, and was hoping to achieve a 4 way design using an 8 ohm bass driver wired in parallel to a series of 3 smaller speakers starting with an 8 ohm mid bass, 4 ohm full range, and 4 ohm tweeter. According to your calculator, this would give me a total of 5.7 ohms… I have the bass driver hooked up to a 500hz low pass filter (the speaker jack type), and the other 3 speakers run off of the full range signal. My questions.. is how can I hook up a crossover network to the 3 speakers in series? I have a capacitor for the tweeter that I calculated for about 5000hz, just to protect the tweeter… but the other 2 speakers are not splitting the frequencies well and it sounds quite muddy… Im a super noob to this.. so bare with me… lol

    Here is the parts list.. everything is from Parts Express

    HP-6020 6-1/2″ Poly Cone Woofer with Rubber Surround 8 Ohm
    Part # 299-2120

    Dayton Audio ND65-4 2-1/2″ Aluminum Cone Full-Range Driver 4 Ohm
    Part # 290-204

    Dayton Audio ND140-8 5-1/4″ Aluminum Cone Midbass Driver 8 Ohm
    Part # 290-218

    Dayton Audio DMPC-7.5 7.5uF 250V Polypropylene Capacitor
    Part # 027-429

    Speaker Wire Terminal Plate with 550 Hz Low Pass Filter
    Part # 269-012

    Dayton Audio ND20FB-4 Rear-Mount 3/4″ Soft Dome Neodymium Tweeter
    Part # 275-035

    • Hi Josh,

      You are discovering why speaker manufacturers charge so much for the designs. It is not easy. I’m an installed, not a speaker designer, so I can’t help too much I’m sorry.

      From the little bit that I know, I’s suggest your current crossover frequencies are not right for the speakers. Every speaker has its optimum frequency range and would need to get those frequencies.

      I also suggest that by wiring the three in series as you have, that none of them are getting enough power to let you hear the mids and highs. You 4 ohm speakers are only getting less than 25% of the power from the amp.

      I’m sorry I can’t help much more, but at least you understand why the only speakers I’ve built were based on proven designs, because I can’t design them myself.

      • Thanks for the reply Geoff, I understand the power difference between the speakers, and actually used 4 ohm speakers to split the power like that on purpose.. as the 8 ohm speakers are much bigger and can handle considerably more power than the smaller full range and tweeter.. So by using the 4 ohm smaller speakers.. it sends more power to the bigger speakers that can handle it.. based on the wattage rating, it’s actually pretty close to optimal for each speaker. (based on your calculator above)

        My question is more regarding the wiring procedure to hook up a crossover in a series. Most of the pre-wired ones appear to be designed for parallel operation.. but I am really just trying to see if wiring a cap between each of the higher speakers.. say if I sent the full range signal to the 5-1/2 mid bass.. the a cap between the mid bass and the 2-1/2 full range at around 5000hz, and then the next at around 10-12000hz for the tweeter. I am no audiophile.. so “optimizing” each speaker really isn’t of much concern… but I would like to try to at least split the frequencies a little better if possible.. I just don’t know if wiring the cap between the speakers in series like this will achieve the desired effect.. Or if there is a way I can wire a pre-designed 3way crossover to work in a series arrangement? Thanks for your reply.. it is much appreciated!

        • Hi Josh,

          As I’m not a speaker designer I may not be able to help much.

          However I think your basic logic is OK, and should not hurt anything to give it a try. You could then play around with different caps to see if you hear any difference.

          My thought is it should work, but the cross-overs will not be tight. But that is only my guess as I don’t pretend to know much about speaker designing.

          Geoff

  10. Hi Geoff!
    I have a 2-channel HiFi amp with 190watts that can handle 6-16ohms output impedance. I have 2 speakers with 6-ohms impedance. Now, I want to add the additional 2 speakers (no specifications stated) that my uncle lend me, is it safe if I just wire them in series?

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