How do I Connect Multiple Speakers to my HiFi Amplifier

I am often asked “How do I connect multiple speakers to my amplifier?” Before I answer, let’s define what we mean by the word “amplifier”. In a stereo “amp” there are two amplifiers – one for the left, and one for the right channel. That is, in the one amplifier box, there are two different amplifiers. In a home theatre amplifier with surround sound, there may be 5, 6, 9 or 11 amplifiers in the one “amplifier” box. For the purposes of this article, we are talking about connecting multiple speakers to a single amplifier only, that is, either the left or the right, or any single amplifier. Of course you can connect multiple speakers to both the left and right amp of a stereo – you just need to follow the principles twice, once for each amp.

Multiple Speakers on One Amplifier

Multiple speakers - Connecting two speakersBy adding an extra speaker to the output of an amplifier, you are adding to the load of the amplifier. That is, two speakers is double the load of one speaker. Most amplifiers can cope with a load of two speakers. Similar to a passenger on a small motor bike: add another passenger and the load the bike needs to carry is doubled, but most bikes will cope with two passengers.

However adding more than two speakers will normally overload the amplifier. Similar to the motor bike example: it can cope with two passengers, but starts to struggle with 3 or more passengers. Most modern amplifiers have some sort of limiting circuit to stop the amplifier working if it is overloaded. In some amplifiers, this involves blowing a fuse inside the amplifier. In other (more technical) amplifiers they will automatically turn off until you turn it back on with a load that is under its maximum safe load.

Amplifiers may cope with multiple speakers at low volumes,multiple speakers - bike example (400 x 267) but will have issues when running at high volume levels. Similar to the motor bike illustration: it may cope with 3 or 4 passengers while going slowly on a flat road, but it will struggle when asked to work harder (like go up a hill or go faster). To be safe, never overload your amplifier.

To understand the technical reason for this, I strongly encourage you to read through the technical explanation below. A good overview on this can be found in the video in the article on Understanding Speaker Impedance

If you just want to know how to wire two speakers to one amp, (4 speakers to a stereo) without switching or individual volume control, see the article on How to connect 2 speakers to 1 amplifier.

If you want speaker on/off or individual volume control, or you want more than two pair of speakers, (like three, four or more pairs) connected to your HiFi amplifier, see the article How to wire four speakers to one amplifier.

If you need to wire more than four pairs of speakers, particularly in a commercial installation, see the article on Distributed Speaker Systems.

Technical Explanation

In the specifications for a hifi amplifier might say Output: 100 watts @ 4 ohms

This is normally specifying the maximum power output of the amplifier and the minimum resistance in the speaker circuit. So in this case, the amplifier will produce 100 watts of power when run at full volume connected to a speaker load of  4 ohms. The ohms bit is our main concern. Ohms is a measurement of resistance. In the case of speakers, it is the measurement of how much resistance the speaker has in the circuit connected to the amplifier. Technically speaking, the resistance of speakers is called “impedance”, as the output of an amplifier is AC, and resistance in an AC circuit is called impedance.

To understand what all this means, we need to get technical and use some formulas. An explanation of these formulas can be found in the article The Dreaded Ohms Law. multiple speakers - ohms law We will use the summary table from that article. You don’t need to understand these formulas but we need to use them.

In our example, we know:

Power is 100 watts: P = 100

Impedance is 4 ohms: R = 4

So we can use the various formulas to calculate the output voltage(V) and current(I) of the amplifier.

Calculation of output voltage(V):

V=\sqrt{P\times R}=\sqrt{100\times 4}=\sqrt{400}= 20\ volts

Calculation of output current (I):

I=\sqrt{\frac{P}{R}} =\sqrt{\frac{100}{4}} =\sqrt{25} =5\ amps

So, from the specifications and a couple of calculations, we now know the following:

Power=100 watts Impedance (resistance) = 4 ohms Voltage = 20 volts Current = 5 amps

An equivalent circuit will help us visualise what is happening.

multiple speakers - connecting 1 4 ohm speaker

This illustrates the maximum capacities of the amplifier. With a load impedance (speaker) of 4 ohms, the amplifier needs to deliver 5 amps to produce the 100 watts of power. This amplifier will normally have some sort of limiting circuitry to limit the current output to no more than 5 amps. The reason being, all the electronics will be designed to deliver 5 amps. Therefore to avoid “blowing up” the output stage (and possibly the power supply), some form of current limiting is employed. The most simplest form of a current limiting circuit is a fuse. If a 5 amp fuse is placed in series with the output, then it would supply the current until the total current exceeds the 5 amps at which point it would “blow”.

Remember, these are the maximum ratings of the amplifier. In practice, many speakers are made to have an impedance of 8 ohms. Therefore the equivalent circuit would be similar, but with a different impedance, therefore a different current as shown here:

I=\frac{V}{R} =\frac{20}{8} =2.5\ ampsmultiple speakers - connecting one 8 ohms speaker

The power output of the amplifier is also reduced:

P=\frac{V^2}{R}=\frac{20^2}{8}=\frac{400}{8}=50\ watts

In practice, because the speaker impedance is increased, the load is decreased and the amplifier is capable of outputting around 23 volts which gives a maximum power output of 70 watt @ 8 ohms.

The important principal is: the higher the speaker impedance, the less current required from the amplifier. Also, the lower the speaker impedance, the more current required from the amplifier.

OK, this is all very good, but what about connecting two or more speakers to the amplifier? Glad you ask, this is the fun bit. Let’s connect two 8 ohm speakers to the one amplifier.

multiple speakers - connecting 2 8 ohms speaker in parallel

You will notice that each speaker still draws 2.5 amps from the amplifier. So the combined load on the amplifier is now drawing a total of 5 amps (2 x 2.5=5). You may have noticed that this is the same current (and therefore the same total load) as one 4 ohm speaker. That’s right, two 8 ohm speakers in parallel is the same as one 4 ohm speaker. If you like, you can prove this using the formula for calculating resistances in parallel. If you’ve had enough formulas, just skip this and go to the next paragraph.

\frac{1}{R_{Total}}= \frac{1}{R_1}+\frac{1}{R_2}\ \ so\ \(\frac{1}{R_{Total}}= \frac{1}{8}+\frac{1}{8}=\frac{1}{4}\ \ therefore\ {R_{total}=4\ ohms

The good news is, this is within the specifications of the amplifier as we saw earlier. So, as long as the speakers both have an impedance of 8 ohms (or more), and the amplifier is rated for 4 ohms, then you can safely run the amplifier with two speakers.

Now what do think is going to happen if we are having a party in several rooms and need multiple speakers (like four speakers) connected to one amplifier on the stereo? The circuit would look like this:

multiple speakers - connecting four 8 ohm speakers

If the poor old amplifier can still hold the 20 volts, each speaker is still trying to draw 2.5 amps, meaning the total current draw from the amplifier is 10 amps – way above its specified capabilities. At this point, we hope it has a limit/protection circuit and has turned itself off, or at the very least the 5 amp protection fuse inside has blown. If there is no current limiting circuitry, then quickly turn the power off when you see the smoke rising from the amplifier.

For those who like the mathematical evidence rather than just the pictorial reasoning, the calculation of the total resistance looks like this:

\frac{1}{R_{Total}}= \frac{1}{R_1}+\frac{1}{R_2}+\frac{1}{R_3}+\frac{1}{R_4}\ \ so\ \ \(\frac{1}{R_{Total}}= \frac{1}{8}+\frac{1}{8}+\frac{1}{8}+\frac{1}{8}=\frac{1}{2}

therefore\ {R_{total}=2\ ohms

and then calculate the current:

I=\frac{V}{R} =\frac{20}{2} =10\ amps = smoke.

For an easy way to calculate the total impedance of speakers in parallel, try my simple Speakers in Parallel Calculator.

Keep in mind that changing the total load impedance of an amplifier will also increase or decrease the power output of the 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. 

Multiple Speaker Selector Switches

multiple speakers - 4 way speaker selectorThere are ways of connecting multiple speakers to a HiFi amplifier without causing damage, but not by simply connecting one speaker onto the other. For a detailed and practical outline of how to connect four or more pairs of speakers to a HiFi amplifier, see this article. The simple method (with the limitations listed in the other article) is to use a speaker selector switch. A 4 zone switch will allow up to 4 pairs of speakers to be connected to the one amplifier.

Please note, speaker selector switches are designed for multi-room installs in a home or small low power installs (like an office or cafe). They are generally suited for low power (under 100 watts) amplifiers. They should be not be considered in a commercial install or for use with high output power amplifiers.

Speaker selector switches can use various techniques to allow multiple speakers to be connected to the one amplifier, namely:

  • a series resistor (around 2½-5 ohms) to restrict the minimum impedance of the speakers circuit to this value. This simple series resistor is often marketed as “manual impedance protection” or simply “Protection”. They are normally good for lower powered amplifiers, and the resistor can get hot at high volume levels.
  • combining the different speakers in series and/or parallel to keep the overall impedance above 4 ohms.
  • matching impedance transformers – this is normally the best, but it is also the most expensive.

All these methods allow multiple speakers, but at a lower volume than using just one speaker. This is logical as the signal is being shared by more than just the one speaker. To see how the power is distributed by the different types of speaker selector switches, see my Speaker Selector Switch Simulator.

For a more detailed explanation and summary of the features of speaker selectors, see my Speaker Selector Switch Summary.

Australian readers can see Amazon’s range here.

Instead of using a speaker selector switch to connect multiple speakers to your hifi amplifier you can use impedance matching volume controls, as outlined in the article on connecting four speakers.


Depending on the impedance of your speakers and the rating of your amplifier, you should be able to use two pairs of speakers connected to a HiFi amplifier. However, it is wise to use the example given above as a guide and use the figures in the specifications of your amplifier and speakers to calculate and know for sure what the outcome will be. Otherwise use a multiple speaker selector switch and/or impedance matching volume controls. The video in Understanding Speaker Impedance explains how speaker selectors help with impedance protection

For a practical discussion on how to simply wire just 2 pair of speakers to a stereo amplifier (4 speakers to a stereo amp), see my article on How to connect 2 speakers to 1 amplifier.

For more practical information of how to wire two, three, four or more speakers to one amplifier using speaker selector switches and volume controls, see this article.

Manymultiple speakers -download PDF practical examples of connecting multiple speakers to your HiFi have been discussed in the comments below. If, after reading these discussions, you still have a question please read the FAQs before submitting your question.

Thanks to James from Sydney, Australia who suggested this topic.


  1. Hi Geoff,

    I have an Amplifier (2 Channels) rated at 900W at 2 Ohms load, 600W at 4 Ohms load, and 380W at 8 Ohms load; this is, as written in the specs sheet, the Maximum Midband Output Power.

    Then I have 3 units of identical Speakers (Active Speakers) that each has nominal impedance of 8 Ohms and can handle up to 300W of power.

    Now my option to power up the 3 Speakers using 1 Amplifier is to connect the 2 Speakers in parallel (4 Ohms load) to 1 Channel and 1 Speaker (8 Ohms load) to another Channel. I think this is possible but is there any possible problem I will encounter in this setup?..Is there any other setup you can recommend?

    Very informative site indeed..Keep it up!



    • Hi Don,

      I think your suggestion is probably the best.

      Two possible issues come to mind. Firstly, there may be some level difference between the two channels, but this can be compensated for with the channel volume controls.

      Secondly, as said many times, 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.


  2. Hi Geoff,
    My church has 30 70v (all on 2.5w tap) speakers in it, which as best I can tell are wired together in series and parallel, and they are all being driven by a crate spa200 watt amp which is not 70v. I am confused as to how this is even possible, unless there is a transformer somewhere that I’m not seeing, however I don’t think there is as I see all the speaker wires coming down into the sound box and then they combine into one and plug into one quarter inch output.

    • Hi Terry,
      I agree with you, it is not the best way to do it.

      I’d assume all the speakers are in parallel. In that case, the total impedance will be 66 ohms. A low impedance amp (designed for 8 ohms) will work into 66 ohms, just not to its best.

      According to a manual I found online, the SPA200 amplifier is rated as 70 watts into an 8 ohm load per channel. So working into a load of only 66 ohms, it will generate less than 10 watts.

      So I suggest the amp is turned up fairly high. If you were to put a transformer between the amp and the speaker cables, you will get a lot more gain if you need it. It will likely sound better too.

      For those readers who don’t know what we are talking about, see my article on Understanding Distributed Speaker Systems.


      • Thanks for the info! Just one more quick question since I’m having a hard time wrapping my head around speaker impedance. The speakers we have are over 20 years old and sons like crap (although like u said that may be due to lack of a transformer). We have new speakers that we are waiting to install, so our main room which had 18 speakers on the 2w tap will now have only 3 speakers on the 6w tap, and there will be 8 more in other various rooms on the 2w tap.
        Will that make it easier on the amp with less speakers? Or should we still get a transformer?

        • Hi Terry,

          I would still get a transformer.

          The lighter load means the amp will deliver even less power without a transformer.

          The beaut thing about using a 70 volt system is you don’t need to worry impedance. Simply add up the total load. In your case, that will be 3 x 6 = 18 watts, plus 8 x 2 = 16 watts, so all together the load will be 18 + 16 = 34 watts. You could use a 50 watt transformer, or 2 x 25 watt transformers and put one on each amp (left and right)


  3. Hi. I wanna connect two speakers to one Port of Samsung home theater ht-f450k.
    What is your advice?

    • Hi Harris,
      All in one systems like yours are normally designed to work with the matched speakers that come with it. This seems to be case with yours also. I wasn’t able to find much info on it, but it appears the amp is designed for a speaker impedance load of 3 ohms (and presumably the speakers are 3 ohms also). Adding another speaker in parallel would put too much load on the amp.

      However you could add another set of speakers in series with the current speakers. They will not be any louder (as both speakers need to the power from the amp) but it could help if you want them in another room. For details in how to do this, read the article on connecting 2 speakers.


  4. Hi Geoff – thanks for this, really useful.

    I’m planning to update my amp to a Yamaha RH602, and a planning to run 2 pairs of speakers from it. I will need to buy a new pair of speakers (8 ohm), but my existing speakers specify 4-8 ohms (Eltax monitor iii’s) and I’m not sure if this will put too much load on the amp (does it mean the speakers run at 4 or 8 ohms?!?). To add confusion the Yamaha spec suggests it can run at a load of 4 of 8 Ohms. I’m confused and would really appreciate your view. Would prefer not to have to buy a selector switch if poss.

    Thanks for your help,


    • Hi Drew,

      Every speaker has varying impedance depending on the frequency it is measured at. Most manufactures market their speakers are nominally 4 ohms or 6 ohms or 8 ohms. This is a biased average, which can normally be safely used in calculating total impedance etc. It seems that Eltax are saying their speakers’ impedance will be between 4 and 8 ohms over the normal frequency range. While this doesn’t help in making total impedance calculations easy, it does highlight that any such calculation is a guide only as impedance is only static at one specified frequency.

      So what should you do? Well it depends on your intended listening.

      If you are mainly going to use one or the other set of speakers, that is, only set at a time, then there is no issue at all. If you are going to have both on at the same time then some more thought is involved. In the worst case, you have a 4 ohm and 8 ohm speaker in parallel. That is total load impedance of 2.67 ohms. This is below the load impedance the amp can cope with at full power. However at low power outputs it wont know. If you are going to only occasionally use both sets at once and only at low levels, then it should be OK.

      If you want to use both sets at higher power levels, then you may want to play it safe and wire them in series. Of course this can’t be done using the A/B switches on the amp. However using a simple series-parallel type of speaker switch would overcome this issue, give you on/off control of each speaker, and give you maximum power when using any one set. You can see this using my speaker selector simulator.

      Hope this helps


  5. Hi Geoff

    Excellent explanation. Lot of the concepts are very clear.
    I have a setup of 8 speakers each rated at 8 ohm. Long term power handling of the speaker is mentioned at 16W.
    The amp is rated at RMS output power of 350W.
    Can I connect a pair of speakers in series (16 ohm impedance) and wire 4 such pairs in parallel to get a net impedance of 4 ohms?
    I am not sure of the power each speaker gets. Will it be more than the rated 16W mentioned for the speaker?

    • Hi Ashish,

      Your calculations are correct. Connecting the speakers in the series/parallel arrangement as you suggest will sort out the impedance issues, as long as your amp is capable of driving a 4 ohm load.

      Each speaker will get 1/8 of the power from the amplifier. So if you only turn the amp up to output around 8 watts, each speaker will get 1 watt. If you turn the amp up to provide 80 watts of power, then each speaker will get 10 watts (and probably be fairly load).

      Obviously if you turn the amp up full, then 350/8 = 43.75 watts = blown speakers. Just make sure you don’t turn the amp up to extent that your speakers distort.


  6. Hi Geoff, all I’d like to say what a great site you have, loads of information. I have a couple of questions. Amongst a few vintage amps as well, I have a Marantz PM7004 stereo amp which is rated at 70 watts per channel at 8 Ohms and is very nice sounding , very clear, detailed and warm. I recently bought a pair of Wharfedale Diamond 240 floorstanders which are also very nice. They are rated at 4 Ohms. However, despite 2 x 8” woofers, I feel perhaps the bass is somewhat lacking at low to moderate levels, though at higher volumes it’s there in spades. But I don’t generally listen at high levels often. My first question is – would a more powerful amp give me a stronger bass response at lower levels? The Marantz does not have a loudness function like say the Yamaha AS500 does. Or is it more likely the bass will open up after more playing time? I only bought the speakers a week ago and have probably only done a total of 2-3 hours. In fact, after listening last night I swear the bass has already started to become more prominent and detailed. But I do wonder about a more powerful amp. I don’t wish to use a sub, nor am I looking for earth-shaking bass, just a fuller bass presence at those lower levels.
    Another question is – the back of the Marantz has descriptions for speaker set A = 4 – 16 Ohms, set B = 4 – 16 Ohms, and A + B = 8 – 16 Ohms. Does this mean I shouldn’t run a second set of speaker (8 Ohms) if the main set (A) are 4 Ohms? Your thoughts are much appreciated.

    • Hi Paul,

      I don’t think a bigger amp will make much difference, as at the lower volume levels it will be the same power reaching your speakers. It seems the speakers are too low in the bass frequencies compared to the highs at lower volume levels. It is possible the woofers will loosen up a bit as they bed down, or at least you can think they do, whether they actually do or whether you get more used the sound or both.

      The speaker impedance notice on the back refers to the fact that the amp will work with a load impedance as low as 4 ohms, but no lower. Hence one set of speakers can be 4 ohms or 6, or 8 or even 16 ohms, as these are all 4 ohms or higher. If you use a second set on the B terminals, the total load of speakers A and B still needs to be 4 ohms or above. Therefore both sets of speakers need to be 8 ohms or above each, as two 8 ohm speakers in parallel gives a total load impedance of 4 ohms.

      Since your new Wharfdales are 4 ohms on their own, you can’t add any other speakers in parallel. You can though use a 2 way speaker selector switch which will connect both in series when you run both, but will connect one set directly to the amp if one set is selected.

      hope this helps


    • Thanks for your reply Geoff, very informative indeed and much appreciated. I still really like the Wharedales a lot and they would go nicely with other set-ups elsewhere in the house if need be. Out of curiosity, do you have any recommendations for 8 Ohm speakers that have a good bass presence at lower levels that would go well with the Marantz? Again, many thanks.

      • Hi again,

        I’m sorry I don’t know the domestic speaker market very well. Even if I did, I could only say what I like based on how I like my sound to be with my type of music.

        My only suggestion is to take a CD (or other source) with the type of music you like. Use this CD when auditioning possible candidates. Also try to find a demo room with similar acoustics to your room. The same speakers will sound a lot different in a reverberant room compared to a “dead” room.


  7. Hi Geoff,

    I have a Marantz 2215b that I got repaired recently. I also bought a set of Bose 301 speakers to upgrade from my small 4 Ohm Philips spealers.

    Since the Marantz 2215b can connect two sets of speaker (“main” and “remote”), I was wondering if I could hook up both sets.

    Do you know if there is any wrong about connecting my 8 Ohm Bose speakers (e.g. in “main”) and my 4 Ohm speakers (e.g. in “remote”)?

    I would understand if both sets would not give the same volume output, but I want to see if I can fill up my room nicely with this setup.

    I can also switch between “both”, “main” and “remote”.

    Many thanks for your reply!

    Kind regards,

    • Hi Christiaan,

      From the specs, the amp is only 15 watts into 8 ohms. I can’t find a user manual, but it appears the minimum load impedance should be 8 ohms, so even the existing 4 ohms speakers would be too low if the amp were running at full power.

      Connecting both the 4 ohms and 8 ohms speakers via the rear panel and using the main/remote switch would be fine if you only had one set on at a time. But using “both” would give a total load impedance of 2.7 ohms which is pretty low.

      To run both sets together, you should either: wire them in series, or use a 2 zone speaker selector switch, which will sort out the impedance issue for you.

      Hope this helps,


      • Hi Geoff,

        Thanks for your reply.

        So you suggest that the mail/remote speaker connections on the amp make parallel connections, correct? Is that logical that their made it that way?

        I did find a service manual of the amp online which also features some wiring schemes, but I cannot make anything out of it.

        And connecting the speakers in series would make 12 ohms, right? Would that be fine for the amp, is there no impedance maximum?


        • Hi Christiaan,

          I also found the service manual, and the best I could make out from the schematic diagrams is that the switch simply parallels the two outputs.

          I agree, this is not smart, but it is simple, and most amps do it this way. I have only seen a few which connect them in series.

          Most amps made this way are designed for a load impedance down to 4 ohms, and on the back they say if connecting two sets of speakers they must be 8-16 ohms each.

          Your are also correct in saying that connecting your two speakers in series will give a total load imednace of 12 ohms. The amp will have no problem with this load, but it will be marginally less powerful. For a further explanation of this, see the article on Speaker Impedance and Power.

          Hope this helps a bit more


          • Hi Geoff,

            Many thanks for your elaborate replies and efforts.

            There is not much written on the back of the amp but I trust (based on your nice articles) that the amp will drive the 12 ohms well.

            I think I will try connecting the speakers in series first. In practice, would that mean that I need to run a wire from the plus on the amp, to the first speaker, then from there to the next speaker, and the same for the minus? Or is there a way to work with less wiring?
            I already have my 8 ohm set connected normally.

            Lastly, is a speaker selector switch a pricy component? Anything to be careful for when looking for such a device?

            Thanks again!
            Kind regards.

  8. Hi Geoff –

    First off, thanks for putting the time into this excellent post.

    I need to configure a sound system for a new store that my wife is opening. It is approximately 30’W x 50’L with a 15′ ceiling. It will be a women’s clothing store and they’ll be playing electronic dance music most of the time – not necessarily loud, but the music will be part of the overall experience. I really enjoy good sound (I’ve got a Marantz system with Paradigm Reference speakers) so maybe I’m over concerned, but here are my thoughts.

    We need to put this system in on the cheap for now. Originally I was thinking we could use a $150 home amp/receiver and hook up 6-8 speakers in the ceiling plus a sub-woofer. But I just learned about 70V systems and now am considering getting something like an Atlas Sound AA35 and hooking up 6-8 Atlas FAP62T speakers to it.

    The cost for the two options comes out to about the same. My concerns with the home system is longevity and how to run the speakers properly. My concern with the 70V system is sound quality, especially bass. The system would be on about 10 hours a day, 7 days a week.

    Any thoughts on which way to go and instructions on how to do it would be appreciated.


    • Hi Jenagah,

      I think your 6-8 speakers is on the right track. Although being 15′ high the coverage of each speaker will be around 25′-30′, so you could get a way with just two speakers (see the speaker dispersion calculator). The Atlas FAP62T speakers look to be good, and should be for that price. The cumulative bass from them might surprise you. If there is not sufficient bass, you could add a self powered sub in the future.

      I’m a bit concerned about the amp though. It looks too small to me. According the Amplifier, Speaker & SPL Calculator, you need about 10 watts to get a 85dB level at standing height (10′ from speaker). If you use 8 speakers, then you need at least 80 watts, so use something like a 120 watt to be safe, and leave plenty of head room. If you use less than 6-8 speakers, I’d put the extra money into a better amp (either stereo or 70 volt).

      hope this helps some,


  9. Hi Geoff. Great website. Just wondering if I can use a powered sub to help drive an extra pair of speakers? So my amp powered 4 while with a line out to my powered sub and then I can try and use the amp in my sub to power an extra set. Is it possible?



    • Hi Graham,

      In theory your idea might work. However most sub amps are designed to only amplify the sub frequencies, not the whole frequency range. Often this could just be a filter on the input, but often this is not defeatable easy. If there is a by-pass switch on the sub then it would be worth a go. Although presumably you would have to disconnect the sub speaker also.


  10. Hi Geoff,
    Your website is very informative – I have learnt a great deal from it in a relatively short space of time and I’m now hoping you can help clarify my understanding and ensure I’m on the right path…

    I’ve recently purchased a house with 4 pairs of speakers: 2 in the lounge, 2 in the kitchen diner. The cables all exit to a cupboard in the kitchen and each speaker appears to be wired separately ie I have 8 sets of wires marked for its corresponding speaker so I’m assuming this is the equivalent of parallel wiring. Changing the wiring to series would be impractical so I’m a bit limited.

    The speakers are all Monacor 12w 4Ohms which also seems to limit my options. I’m looking for a stereo system that will work safely with reasonable sound quality that will work with the existing speaker setup safely. I’m not looking for anything too fancy (or expensive!). I’m considering the Marantz MCR611 which has all the functionality I need. It has 4 speaker outputs with the ability to adjust volume between two zones but an impedance rating of 4-16Ohms. A few questions:

    If I connect all 8 speakers to this, I’m assuming the impedance drops to 2 Ohms which may damage the equipment or worse and reduce the sound quality? If so, I should use a multiple speaker selector switch like the ones you link to? Is there one in particular you would recommend bearing in mind the Marantz MCR 611 and my setup? Or alternatively is there an alternative similar spec hi-fi you know of that would be more suitable. Or have I got it all wrong?! Thanks in advance for any help and for the insight your website has already given me.

    • Hi Joe,

      There are a few options for you to consider.

      1) if all cables come back the cupboard, it is easy to wire two speakers in each room in series (see the top diagram in connection table in this article. Then each room would have an impedance of 8 ohms, and with both rooms on, the total load impedance would be 4 ohms, which should be fine for the map.

      2) You could use any type of 2 way speaker selector switch. For a overview of how each type works, see the 2nd half of the video here.

      Hope this helps,


  11. Hi Geoff,

    thank you for all the information on your website.
    I am trying to find a solution for a setup for a while now, but all that seems to change is that my hair also gets grayer every time I attempt it.
    We bought a house a few years ago that has 3 speaker zones: the entertainment area, the great room and the outside. All wiring comes together in an A/V closet. The entertainment area has a 7.1 surround sound setup. The great room and outside only have 2 speakers each. I have a Sony STR DN840 receiver that has speaker outputs for one 7.1 surround sound zone. What I am trying to accomplish, is having that receiver power all 3 zones. Now, the outputs on the receiver for the one zone are for the 7 speakers, which ones would I use to ‘split’ to the other 2 zones with a switch? The front ones? I am OK if the surround sound in that one room goes from a 7.1 to a 5.1 system when the other 2 zones are switched on, but like to preserve the 7.1 system when the other 2 zones are off.

    Thanks for any help.

    • Hi Norman,

      There are a couple ways you could go.

      Certainly, connecting a 4 way switch (with impedance protection) to the front speakers is a good way. When you want the great room (zone 2) and/or the outside speakers (zone 3) simply select and deselect the zones as required. The Lounge front will be connected to zone 1 of the switch. When running more than one zone, turn on the speaker protection switch, which inserts a resistor into the speaker circuit to maintain a minimum load impedance for the well being of the amp. However when only running one zone (like when watching a movie) you can turn this switch off and all the lounge speakers will appear as per normal.

      The only real possible issue with this method, is even when you deselect the main speakers, some signal may still come through the surround speakers. However can turn this off by using the appropriate stereo mode on the amp.

      Another issue may be that you want one of the other zones louder or softer than your lounge room, which you can’t achieve. A way to solve this would be use a ‘slave” amp for the outside and great room speakers.

      Hope this help (and remember we worked hard to get the grey hairs!)


  12. hi there, i am also new to this and i want to add 2 speaker sets 8 ohm (4 speakers) to the following installation.
    Is this possible? or else i should use a speaker selector such as this ?

    harman kardon amp: AVR 151S (375w 5.1)
    Stereo power: 75W per channel, two channels driven @ 6/8 ohms,

    with these speaker set:
    Harman Kardon HKTS 5
    4 x Satellites
    • Recommended power: 10W – 80W
    • Impedance: 8 ohms nominal

    thanks in advance for the attention

    • Hi Paligkostas,

      You are correct in that it is best to use a speaker selector switch. The one you mention is a series/parallel type. This means that the speakers connected to outputs 1 and 2 are connected in series, as are any speakers connected to output 3 and 4. Then these two sets of outputs are connected in parallel.

      So if you connect your two new sets of 8 ohm speakers to outputs one and two, they will be connected in series when both are selected – this will give a load of 16 ohms. Then your existing front speakers (8 ohms) can connect to output 3. When all speakers are turned on, the total load impedance will be 5.3 ohms, which most amps will be fine with. Connect the input of the switch to the front speaker terminal of the amp

      hope this helps


  13. Hello, I am searching for an amplifier to drive an outdoor pool/patio system.
    I have an Oknyo TX-8050 two channel receiver with preamp outputs. The amp would need to drive a JBL Control SB210 sub with crossover and four JBL Control 28 Satellites speakers.
    (1) JBL SB210 – 400 watt 8 U x2
    (4) JBL 28 – 175 watt 8 U each
    JBL set up is two channels from the receiver to the amp to the Subw/crossover and from there to the two satellite speakers for each channel.
    If I did the calculations correctly, I need an amp that has 1600 watts at 4U with 80 volts and 20 amps.
    Do the calculations work if I’m going thru a subwoofer with crossover? Are my calculations correct? Can you recommend an amplifier that has these specs?

    • Hi Delway,

      What amp you need depends to some extent on how loud you like your music and what type of music. Have you tried running these speakers off your Onkyo? For most domestic setups they would work well together. Remember the power ratings on the speakers are the maximum power capabilities, not the required amount. They will work well with much less.

      If you want some real grunt, you would be better off using a commercial amp, something like a Crown. A quick search on Amazon shows this one.
      It has a built in cross over, so one channel would drive the sub, and the 2nd channel would drive the 28’s. You would ideally need two such amps, one for the left and one for the right channel (they are pretty cheap for what you get). You would need to be careful that you don’t over drive the 28’s with this amp though.

      I don’t like recommending a particular amp as everyone’s needs, expectations and budgets are different, but something like this one would work well. Just remember, if you hear distortion, it means impending damage – so turn it down.

      Hope this helps some. Please come back if I’m on e the wrong track you were after something different.


  14. hello geoff, like most people, i too am a little confused… i have a sony ta-fe370 amplifier with an impedence of 4-16Ω. i have 2 sets of sony speakers; one set with a rated impedence of 6Ω and the other set rated 8Ω – can i connect 1x 6Ω + 1x 8Ω to the R channel, plus same for L channel ? thanks, tom

    • Hi Tom,

      A 8 ohm speaker and a 6 ohm speaker in parallel gives the amp a total load impedance of 3.4 ohms. This is slightly below the minimum impedance the amp is designed to work with at full power.

      So your options are:
      1) Don’t run the amp at full power
      2) connect the speakers in series, this will give a total load impedance of 14 ohms – within the working range of the amp
      3) Use a speaker selector switch which will increase the impedance seen by the amp

      hope this helps


  15. Hi Geoff

    Great work! And thanks for being so helpful 🙂

    One small question if you dont mind….

    I have a 60w stereo capable of handling 4speakers.

    Is it ok to connect 2 speakers of 120w each on 2outputs? Would that mean that i have used the stereos’ 4 amplifiers? Or is the stereos 60w capability split up between the 4, thus only capable of handling 4 15w speakers?

    Thanks !

    • Hi Joe,

      It can be confusing can’t it?

      If your stereo is rated at at 60 watts, that normally means each of the two amps (left and right) inside are rated at 60 watts.

      If your amp has two outputs, like speakers A and B, this is normally just a convenience for you to connect and second set of speakers (set B). But they are still connected to same amps as set A.

      So, the power is shared between them when both are on. You can still drive a 120 watt speaker with 30 watts of amp, the speakers just wont reach their maximum possible volume, but it will still work fine.

      More importantly is the total impedance of each pair connected. Most amps don’t like driving a total load impedance of less than 4 ohms. Hnece they often have a warning on the back that says something like: for A+B use 8-16 ohms speakers. This is because two 8 ohm speaker together will give a total load impedance of 4 ohms.

      hope this helps


  16. Hi Geoff,
    First let me thank you for the great explanation. I am trying to grasp all this info and understand all the ways to connect speakers to an amp. I have an old AKAI AA-1010 amp. On the back of the amp, I am trying to understand the way the amp is designed. I see speaker A with R & L( with four outputs ) then speaker B with again R & L. ( with four outputs)

    In your article, you mentionned left and right channel. Does A and B means the left and right channel?It also says on the back speaker ( 4-16 Ohms) then speaker A+B ( 8-16 Ohms). What does that mean?

    I did connect my speakers to only A ? Am I doing it right? I am guessing B is if you are trying to connect another set of speakers??

    Thank you to help me on this one.



    • Hi Mike,

      It appears you have connected your speakers up correctly.

      The naming of the connections can be difficult at first. let me try to explain.

      In your stereo amplifier box there are two amplifiers. One for the left channel and one for the right channel. So the speaker connectors on the back are marked “L” and “R” are for the left and right speakers.

      Your amplifier also has a built in 2 way speaker switch – useful if you wanted to have speakers in two rooms. You could have speakers in Room A and also in Room B. Hence you have connections for Room A (L and R), and for room B (L and R). Still only two amps, each with two possible outlets. Hence on the front panel there is a speaker switch which allows you to select the speakers in Room A, or Room B, or both.

      Now we need to get technical. As discussed in the article, when you add a 2nd set of speakers you are doubling the load. Basically your amp can cope with a load impedance of 4 ohms or higher. That is why it says on the back “4-16 ohms”. So for one set of speakers, the impedance of those speakers can be 4-16 ohms. However if you are having two sets of speakers connected at the same time (A + B), then each speaker needs to be 8-16 ohms, so that when they are connected in parallel (both on at the same time) then total load impedance doesn’t fall below 4 ohms. Two 8 ohms speakers in parallel totals 4 ohms – all good. Two 4 ohms speakers in parallel totals 2 ohms, not good for an amp designed for 4 ohms or more.

      does that help?


  17. I have a Sony DAV TZ 140 Home Theatre System 50w per channel@ 8ohms.
    I would like to add 2 additional 67w speakers 3ohm in parallel to the two front speakers into the next room. Is this possible or advisable and will it adversely affect the system?
    Should I rather connect the additional speakers in parallel to the central speaker but then I won’t have stereo sound?
    Your advice please and thanks for a most informative site

    • Hi Andy,
      As you probably know, these all-in-one systems are fairly basic and don’t allow much expansion. In fact on the instructions for your unit is specifically says “Do not use any speakers other than those supplied with this system.”

      However there are two ways I can think of to help you out.

      The best way would be to use a second amp. It doesn’t need to be big or new. Connect the input of the second amp to the line out of the Sony and then you can adjust the volume of the second set of speakers to any level you like via the volume control of the second amp, and there will be no chance of disturbing the Sony.

      The other way would be to use a 2 zone speaker selector switch which uses a series resistor for impedance protection. This will keep the minimum impedance close to the 8 ohms your amp wants.

      hope this helps


  18. I have just purchased a small replacement Hi fi mini system pioneer rating of 30w with two 8ohm speakers,I would like to connect two additional speakers in the kitchen using the old Sony speakers which are 6ohm,is this possible to carry out with a selector switch without damage to the amp.


    • Hi Derek,
      You should be able to use a speaker selector with no problems.

      You only need a selector if you need to turn one set on or off. If you want both sets to work all the time, you could simply wire them in series.


      • Geoff
        Thanks for your info I will go ahead to connect them and let you know if there are any problems.

  19. Hi Geoff
    1.My wife is very deaf and uses a set of bluetooth wireless bone conduction headphones to listen to music from her ipad. She would also like to be able to use these headphones with our (old but very good) hifi system so we can both listen to music from it at the same time ie she wants to use her bluetooth headphones at the same time as I am listening through speakers. I know I can get a bluetooth transmitter which plugs into the headphones socket of the amp, but the problem is that the phones jack cuts off the speaker sound. Is the only way round this for me to open up the amp and solder closed the socket contacts which are pushed apart by the inserted plug? (that is, if they are accessible and not hidden inside a lump of plastic).

    2. Some modern upmarket portable radios/systems have a “line out” socket. Does this cut off the speakers? If not, could this be used with a bluetooth transmitter to enable simultaneous phones/speaker use?


    • Hi Jeff,
      There are several option I can think of for you.

      Modifying your amp headphone socket is possible, but you would have to ensure you don’t bypass the dropping resistors in the process. Most amps use a resistor around 330 ohms to drop the speaker level down to headphone level. This is normally wired across the “switch” so you may have to modify it more than you think.

      An easier way would be to use one of these converters. These will connect to the speaker connections of the amp (along with the speakers) but give you a line level output which your Bluetooth transmitter will connect to.

      A possible issue with either of these solutions is that the level to her transmitter will vary every time you change the volume. To overcome this, it would be best to use the “line out”. I’m surprised your old Hifi doesn’t have a “record out”. Most older units had this facility to allowing recording on an external cassette player/recorder. If it does, you could use this to feed the transmitter.

      If this doesn’t help, let me know the model of your amp or send me a picture of the connections on the back and I’ll try to find a better solution.


  20. Hi, I think I have a pretty simple question that may have been already answered on this page, if so I apologize. I simply want to power 4 of these speakers on my patio from my TV (using headphone jack) to this or something like it. I’m not too technical on ohms etc. Can you direct me to a cheap amp on amazon that will be sufficient? Note that this is an outdoor setup and does not need to be super loud or super hifi. One thing I’d like to avoid is the “pop” when powering on. Additionally, I’d like to make sure I can control the volume of the speakers with the TV remote. Thanks so much!

    • Hi Pete,
      The system you suggest will work well for a budget system. Many people would use a more powerful amp, but if the specifications are correct for that amp, it should provide sufficient sound for your use.

      You will be having two speakers on each channel (left and right). Since those speakers are 4 ohms, you will need to wire them in series, to make up 8 ohms. See my article on how to wire 2 speakers, for more on this.

      Being able to control the volume through the TV remote is a function of your TV – most will change the headphone volume. You may need to go into the sound menu of the TV and turn off the TV speakers if you don’t want the sound coming from the TV also.

      The thump you get when you turn on an amp is a function of the amp. More expensive amps have special anti-thump circuitry, which your basic unit may or not have.

      hope this helps


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