How to Test Speaker Output With Multimeter

How to Test Speaker Output With Multimeter

It can be very bad if you are having guests over for a party or a birthday celebration and suddenly your speaker stops working.

Luckily, you can learn how to test if your speaker is working properly right here and this same process can be applied to guitar amps.

This will take only a couple of minutes, but it can save you from becoming that guy that had the most boring party ever.


You will need a screwdriver and a multimeter with standard multimeter test leads. If you want to be extra sure that everything is in order, get a 9 volt battery too.

Here’s the deal

Take your speaker or amp and unscrew it with a screwdriver. If there are any additional layers on the inside, carefully remove them until only the speaker and wires are left.

With the speaker still intact, take a look and remember the location of the wires (which wire went where) and unsolder them. If you don’t know from where you should unsolder them, wires are usually soldered on two bulges on the side of the speaker.

Those bulges lead inside the metallic box at the back of the speaker.

Open the box

Be careful while doing the following so that you don’t rupture the speaker’s membrane:

  • When you have unsoldered the wires, you need to unscrew the speaker from the box and remove it.
  • When you have done that, carefully remove the speaker from the box.

Inspect the speaker

Now is the time to visually inspect the speaker.

  • Carefully inspect the membrane for any ruptures and signs of damage.
  • Once you have done that, do the same, gently, with your hand or fingers, depending on the size of your speaker. Obviously, if you locate a hole or a punctured part, the speaker is broken.
  • If everything seems to be fine, yet, there is no sound, the problem could be in the wiring inside the metal case on the back side of the speaker.

Now is the time to use the multimeter

Take your multimeter (by the way you can buy Innova 3340 on -- great choice) and insert the standard multimeter test leads.

If you will be doing this on a smaller speaker, you should probably place the protective caps on the test probes to prevent false readings due to high possibility of accidentally touching the probes in small space.

Check the back side of your speaker to see what is the impendance of your speaker. It is usually printed on the side of the metallic box that contains the wiring. The value of impendance should be around 8 ohms.

It is worth noting that some homemade speakers can have impendances of 2 or 4 ohms, but lower the impendance, the higher stress will be exerted on the speaker.

Test your speaker with the multimeter

  • Set your multimeter on the lowest impedance setting.
  • Place the probes where the wires were soldered, according to poles.

If wiring is broken and you have done everything correctly, the multimeter should show no value.

If your multimeter is showing any value besides lowest ones, like zero, your speaker is OK.

Additional test:

  • There is one more thing that you can do to check it, if you don’t have a multimeter lying around.
  • Get a 9 volt battery and a wire and place one battery pole on the correct place where the wires were soldered.
  • Connect the wire by placing it on the battery and on the free pole on the amp.

If you have done everything as you should, the membrane of the speaker will rise and produce a short deep sound.

!! Just be careful that you don’t get buzzed by the battery while doing this !!


  • If you have 20 dollar speakers and they have stopped working, just get new ones, it will save you a lot of time.
  • While doing the 9 volt battery test, wear rubber gloves.
  • Sometimes a magnifying glass can be of great use to you. This is one of those times.
  • Make sure that your multimeter is calibrated before doing this and be careful to solder the wires back on on correct places on the speaker.

This procedure saved me a lot of time and I was eventually able to repair my speaker.

I hope that you will be able to do the same.

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