SERIES & PARALLEL SPEAKER WIRING

BASICS OF WIRING SPEAKERS

There are several ways to wire up Speakers, the most common methods are Series and Parallel which are discussed here. It is also quite common to wire Speakers in a Series/Parallel Combination.

Wiring up Speakers correctly to provide the best possible sound, requires some knowledge of Loading, Phase, and Impedance, while understanding Ohms Law will help you to connect your speakers properly.

Although we discuss here two ways to wiring Speakers – Series and Parallel , we should mention Series/ Parallel Combination, so we have included a diagram showing this configuration.

SERIES SPEAKER WIRING

The Amplifier sends an audio signal (+) out through the (+) Speaker output into the first Speaker; then the signal is sent from the first Speaker’s (+) and so on until the circuit is complete with the (-) of the last speaker is connected the Amplifier’s (-) connection.

Adding Speakers in series increases the overall resistance of the circuit.

Therefore the resistance of each Speaker is added together, For advanced installations with Multiple Speakers, Series Speaker wiring can be used to increase the resistance of the “equivalent” or “overall” resistance that the Amplifier sees. This allows the Amplifier to run cooler and more efficiently.

Series Circuits are “voltage dividers”, and using Ohms Law, one sees the result as a decrease in amplified voltage audio signal to each Speaker. Since Series Circuits are “voltage dividers” each Speaker sees a percentage of the amplified output from the Amplifier.

It is often assumed the Amplifier is producing less output, but it still produces the same output, because each Speaker only gets a percentage of the overall power.

single speaker with 8 ohm load

4 Ohm Speakers (unlike Speakers at 8 ohms of resistance) keep the “overall” resistance on the Amplifier at or near 4 ohms.

However, increasing the resistance to more than 4 ohms of speaker resistance by adding Speakers in Series, will split the amplified audio output from the Amplifier across all the Speakers in the circuit.

The formular for Series Wiring is: Znet=Z1+Z2+Z3….

PARALLEL SPEAKER WIRING

Parallel circuits are the simplest electrical circuit to wire.

Adding Speakers in parallel decreases the overall resistance of the circuit

Parallel Speaker Wiring combines all Speakers (+) positive Speaker leads together, and all (-) negative Speaker leads together. Parallel Circuits are the simplest to wire because adding a Speaker is as easy as connecting the new Speakers (+) positive lead to the (+) Speaker wires of the other Speakers and the (-) negative lead to the (-) connection of the other Speakers.

Adding additional Speakers is as easy, however, adding Speakers in Parallel causes the overall resistance of the circuit to drop, as resistance drops, the current must increase according to Ohms Law.

So, each time a Speaker with the same resistance is added to the parallel circuit, the current draw on the amp increases. The circuitry of the amp must be able to handle this increase in current at the reduced resistance.

The formula for Parallel Wiring is:

parallel wiring formula

When n is the number of Elements

Note: If more than 2 Speakers are connected in Parallel, so long as they are all the same impedance then the net impedance of the load is equal to the impedance of the one Speaker divided by the total number of Speakers.

For Example:

Three 8 Ohm Speakers in Parallel, the Impedance is 8/3 or 2.667 Ohms.

A COMBINATION OF SERIES & PARALLEL

In reality this is just two sets of Series Speakers wired in Parallel

8 ohm speakers wired in series

Nigel Brent studied at the EMI College of Electronics in London England and subsequently formed a Design Company in Los Angeles, California. His current projects include a range of Miniature Amplifiers for both Traditional Stereo and 70 Volt Applications. Being small enough to fit in your hand, they can be easily concealed, reducing the chance of theft.

Typically they are used for Commercial, Corporate, Restaurants, Schools and Universities. His full range of products can be seen on his Web site www.nigelbdesign.com.

Nigel B Design, Inc. CA USA. Tel: (818) 487-9323 Fax: (818) 766-9805 Web Site: www.nigelbdesign.com . E-Mail: sales@nigelbdesign.com

14 thoughts on “SERIES & PARALLEL SPEAKER WIRING”

  1. How do u add a 5th speaker between the left and right in a series to be the center speaker .

    • You can create a “center” speaker by connecting the + from the left side and the – of the right side to your 5th speaker. You could even daisy chain the connections from the other speakers if you’re installing rear speakers, as opposed to running wires all the way from the head unit.

    • You don’t. This wiring diagram is for getting wide area coverage on one zone of output. Are you thinking about a 5 channel surround sound setup? That would require a surround sound receiver and 5 speakers, each wired to its own output.

  2. Don’t connect series the speakers, because they make low pass filter and high frequences it’s will be a lost.

  3. How would I wire a 3 channel LCR speaker to be a center channel, Each channel is 8 Ohm. The receiver, an Onkyo, will do 6 OHM.

    • Hi Eric, thanks for your comment! Hopefully one of our knowledgeable readers will be able to chime in with some insight on this. This is above my pay grade!

  4. Sounds like you will have to have knowledge of resitors.. good luck…I’ll be interested to see what others have to say

  5. Thanks Deacon! Nigels work here is very easy to understand the Series / Parallel was very helpful to me in my current project…made everything very clear and saved me some headaches…

  6. Is it possible to connect two speakers in parallel and then connect them to one speaker in series? I currently have two vintage speakers (8 ohms each) connected in series for my center channel (of a receiver that puts out 80 watts per channel at 8 ohms). So the vintage speakers combined in series are at 16 ohms and receive 40 watts (20 watts per speaker). This seems to work fine. Is it possible to add a newer 4 ohms speaker to this center channel by connecting the two vintage speakers in parallel (now with a combined resistance of 4 ohms) and then connect these to the new speaker (at 4 ohms) in series. In theory would this combine to make an overall resistance of 8 ohms? With the two vintage speakers receiving a max of 20 watts each and the new speaker receiving 40 watts? I have noticed that none of the diagrams online show this kind of configuration. Is it possible / acceptable?

    • Hi Tom,

      Thanks for your comment. I’m hopeful that another reader will be able to chime in and give you an answer on this one!

  7. I would like to put 3 speakers on The left side of my room and 3 on the other. I’m trying to decide if I need to run them in series or parallel? The space is a 40×40 area.

  8. I am mounting 4 speakers on a patio that’s 16’ W x 60’ L. How should I mount these? What I mean is should I mount speaker A as left, speaker B as right speaker C as left and speaker D as right? Or speakers A/B as left and C/D as right? Then do I wire them in parallel or series? I plan on putting a volume control on the patio as well to control from outside.

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