Speakers need to provide excellent sound. For this reason, some people choose to connect two speakers together. But to do that, it is crucial to understand how two speakers share power.
Speakers can share power if they are wired correctly. When in series, the resistance adds together (2 x 4 ohm speakers = 8 ohms). When wired in parallel, the resistance decreases (2 x 4 ohm speakers = 2 ohms).
To connect multiple speakers together, you need to understand how they share power. It is also crucial that you know a speaker’s determinants of power to find out if two speakers are compatible.
Also read: Do Surround Sound Speakers Need Power?
How Speakers Share Power
Most of the time, people want to connect their amplifiers and speakers to increase audio power. But in some cases, connecting two speakers reduces the power in any of the two. To prevent that, you need to know how speakers share power.
How speakers share power is not too technical. Here is what Geoffrey Sean Petersen, an electrician, and owner of the blog Geoff the Grey Geek, says
“How the speakers share power from the amplifier is dependent on whether the impedance of each speaker is the same or not, and if the speakers are wired in series, parallel or a combination of series and parallel.”Geoff The Grey Geek
However, it is worth noting that connecting multiple speakers together does not double their power. So, you may ask why you even need to add speakers to your amp. The main reason for that is to spread the coverage of the speaker.
Because speakers share power depending on their impedance, you may be asking what impedance is. To understand it better, let us use an analogy.
Think of your speakers as pipes, and the audio signal or the sound you play is the water flowing in these pipes. On the other hand, your amplifier is the pump.
If the pipe is bigger, it will be easier for the water to flow through it than smaller pipes. Additionally, bigger pipes can handle more water flowing through them due to greater volume capacity.
The lower a speaker’s impedance is, the more easily an audio signal or electricity can flow through it. For example, you will see amplifiers that can deliver 100 watts at 8 ohms impedance. Alternatively, some amps are rated to deliver 150 or 200 watts at 4 ohms impedance.
Using this analogy, you can connect two speakers together though they have a different impedance. However, the connection can only spread the speakers’ coverage if the amplifier is powerful enough to push extra power. The reason is that the connected speakers will share the power provided by the amp.
Moreover, as sound goes up or down in pitch, the impedance of your speaker changes as well. For instance, speakers playing at 41Hz might have a 10 ohms impedance.
If you know how the impedance of speakers works, you will be able to choose the speakers that you want to connect.
How Speakers with Same Impedance Share Power
Suppose you connect two or more speakers with the same impedance. In that case, the resulting impedance is the impedance of one speaker divided by how many speakers are connected. So, if you connect four speakers in parallel with an impedance of 8 ohms, the total impedance would be 2 ohms.
Alternatively, you can connect two speakers in a series of wiring. In this case, the total impedance will add. For instance, if you connect two 16 ohm speakers with one 8 ohm speaker, the total impedance in series would be 40 ohms.
However, if you connected the same speakers in parallel, it would be significantly less. Remember that if we have two speakers of equal impedance, they divide the impedance in half (by the number of speakers) relative to the individual speaker’s ratings.
Can You Connect Speakers with Different Impedance?
You can connect speakers with different impedance together. However, the process is a little more complicated than connecting the same impedance speakers.
Before anything else, you need to check your receiver or amplifier and find the minimum impedance rating that it requires. For instance, your amp has a rate of 100 watts at 4 ohms minimum.
Now, take that you have two pairs of speakers with 4 and 8 ohms, respectively. Add the sum of the total impedance for each pair, which in this case is 4 ohms + 4 ohms and 8 ohms + 8 ohms.
After getting the sum of system A and system B, multiply the two together (128 ohms). The product of the two impedance is then divided by the total impedance of the two speaker systems, which is 24 ohms.
So, 128 ohms divided by 24 ohms is 5.33 ohms. Such is within the suitable range of the 4-ohm minimum rating of your amplifier. Meaning you can safely connect the set of speakers without them getting damaged.
Connecting Multiple Speakers in a Series Wiring
When you are planning to wire speakers with multiple voice coils, it is vital that you are well aware of the process of series wiring.
You can wire to or more speaker voice coils in series. To do this process, you need to connect the first voice coil’s positive connection to the positive connection of the amp. Next, attach the negative voice coil connected to the second voice coil’s positive connection.
If there are only two voice coils that you need to wire in series, the second voice coil’s negative connection will need to connect to the negative connection of the amp.
On the other hand, if you have multiple voice coils, you need to repeat the above-mentioned process for every additional voice coil.
Connecting Speaker Voice Coils in Parallel Wiring
Parallel wiring is much simpler than series wiring. In parallel wiring, you only need to wire all the speaker’s positive voice coils to the positive terminal of the amplifier.
Similarly, the negative voice coil connection attaches to the negative amp terminal.
Connecting Speakers Using Series-Parallel Wiring
Often, you will need to use a combination of series and parallel wiring so that you can get your desired impedance. For this method to be more accessible, it is ideal to use an even number of voice coils with the same impedance.
If you have single voice coil speakers, you need to use a minimum of four speakers with the same impedance. After the series-parallel wiring process, the resulting impedance will be the same as the impedance of one speaker.
To complete the series-parallel wiring, you need to series wire two sets of speakers. Next, the second set should be wired in parallel with the other group of speakers.
On the other hand, you need to decide how you will wire the coils on each speaker, either series or parallel, if you have multiple dual voice coils speakers.
You will then take the final impedance of the speaker’s two coils and use the other method that you have not used yet. This way, you will be able to compute the final impedance to the amplifier.
What Determines the Power of a Speaker?
A speaker’s power rating is a crucial consideration for people planning to buy a pair of speakers and connect them together. Usually, you will see the power rating listed with all the other features of the speakers. But sometimes, they are not easy to understand.
However, the problem is that power rating is something that many people misunderstand. That can be an issue, especially if you are trying to connect multiple speakers to create a sound system.
Before anything, you mustn’t get confused between the amplifier and speaker power specifications. Remember that the speaker does not work to generate power. Such is something that the amp does.
Hence, the power rating you see for speakers, measured in watts, refers to the power that the speaker can safely receive from the amplifier.
If a speaker receives more power than it safely can, it will distort and overheat. Such may lead to permanent damage to the speaker.
On the other hand, if the amp supplies power within the speaker’s capabilities, you can ensure that it will not render the speaker damaged.
To simply put it, a speaker’s power rating, known as wattage rating, is the measured limit of electricity a speaker can handle before it burns out. The measurement for this power specification is watts.
Additionally, you can calculate it as a continuous, root mean square (RMS) or peak value.
Minimum and Maximum Power Ratings of Speakers
Looking at the specifications of a speaker, you may find a minimum value for the power listed on it. If you see a minimum figure, the most minor power level is required to drive the speaker to make an audio signal.
However, your amplifier also needs to deliver this power level for the speaker to work.
On the other hand, the maximum figure you will see on a speaker’s specifications is the highest power level that it can handle before distorting. You need to make sure that you are not going over this limit.
However, it is worth noting that that the figures that you see listed in the specifications are pretty conservative.
In reality, you can exceed a little more than the maximum power of your speaker. But you can only exceed the limit for short periods to ensure that you will not damage the speakers.
Reverse Wiring: Common Mistake When Connecting Speakers
One of the most common mistakes when connecting speakers is reversing speaker wires. Of course, the best thing to do is to wire the speakers correctly.
However, the effects of incorrect wiring differ depending on the situation.
In some cases, miss-wiring is unnoticeable. On the other hand, it may cause severe problems in other cases.
Accidental reversal of your speaker wires can occur when the wires are not labeled correctly for polarity. Such an issue results in making the speaker out of phase. It will also cause audio oddities.
This common mistake is not dangerous to your speaker or amplifier. However, the proper delivery of power and speaker response will not be possible if you mistakenly reverse speaker wires.
Below are the problems that can occur as a result of reverse wiring:
- No bass
Bass’s response is one of the primary things that suffer due to reversed polarity. Speakers form bass tones by putting pressure on the air in the space that surrounds the speaker.
If the signal is out of phase, the bass speaker will move in when it should move out.
As a result, drum notes will become inaudible, causing the music to lose impact.
- Unclear Treble
Incorrectly wired speakers cause high frequencies to lose their focus. It causes airy treble, which makes the audio sound larger but less defined between each speaker.
Some people want this effect. However, it is still inaccurate in audio production. The reason is that it will affect all the drivers. For this reason, Techwalla noted that “this brand of high-frequency response also comes with a poor imaging and thin bass penalty.”
Notably, Techwalla is one of the reputable online sources of technical information for homes.
Imaging happens when two speakers project an audible representation of different instruments in the audio.
If the speakers are incorrectly wired, the sound of instruments becomes out of focus. In addition, the sound becomes sonically disorganized.
Such is especially true since miss-wiring affects the other drivers in the speakers.
Additionally, you can find mid-range frequencies in the bass and tweeter drivers. If the wirings are revered, it causes a collapse in the dynamic stereo information. For this reason, music will lose most of its impact.
- Geoffrey Sean Petersen, How Multiple Speakers Share Power, https://geoffthegreygeek.com/multiple-speakers-share-power/
- Brent Butterworth, What Speaker Impedance Means and Why It Matters, Lifewire, https://www.lifewire.com/speaker-impedance-3134705/
- How to Power Two Speakers with a One Channel Amp, WikiHow, https://www.wikihow.com/Power-Two-Speakers-with-a-One-Channel-Amp/
- James Clark, How to Mix Different Ohm Speakers, Hunker, https://www.hunker.com/12475102/how-to-mix-different-ohm-speakers/
- Series, Parallel, and Series-Parallel Speaker Wiring, Kicker, https://www.kicker.com/app/misc/support/tech/tech_papers/docs/SeriesAndParallelSpeakerWiring.pdf/
- Understanding Speaker Power Rating Specifications, The Home Cinema Guide, https://www.the-home-cinema-guide.com/speaker-power-rating.html/
- David Lipscomb, What Happens If I Reverse My Speaker Wires?, https://www.techwalla.com/articles/what-happens-if-i-reverse-my-speaker-wires/
Jason is a home theater expert with over 10 years of experience in setting up home cinema rooms and systems. What started out as a hobby soon transformed him into an authority in the audio-visual field. He is passionate about providing readers with accurate and up-to-date information on the latest audiovisual technologies and their applications for home theaters. Read more about Jason.