How do I calculate the impedance of multiple speakers?

If you have 2 speakers wired in series, then simply add their individual impedance together. For example: A 4 ohm speaker in series with a 8 ohms speaker: 4 + 8 = 12 ohms.

If you have 2 or more speakers in parallel and all the speakers are the same impedance, then divide that impedance by the number of speakers. For example: if you have three 8 ohm speakers, then 8 ÷ 3 = 2.67 ohms.

If you have 2 or more speakers in parallel and all the speakers are not the same impedance, then it is easier to use my Speakers in Parallel Calculator.

Note: all these calculations are for connecting manufactured speakers (boxes). They are not used when building your own speaker box and connecting multiple speakers in a cabinet using a crossover circuit. A crossover splits the signal into different frequencies for each of the speakers and makes the total impedance calculation complex (as impedance is frequency dependent). That is why speaker designers get the big money, and as installers we benefit from their expertise.


Please Note: During the Covid-19 pandemic I'm busy with a number of streaming projects, and have very limited time to attend to this website. I'm currently taking up to a week to answer questions. Sorry for any inconvenience.

Disclosure: If you buy through this Amazon USA link Geoff receives a small commission from each sale.
European and Australian readers can use the links on the side panel - Thanks for the support


Please enter your comment!
Please enter your name here

This site uses Akismet to reduce spam. Learn how your comment data is processed.