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Is Equalizer APO Not Working? Here’s How You Can Fix It

You don’t have to work in the music industry to use an Equalizer. It is one of the basic tools to modify the audio played through your headphones or speakers. Windows Operating System doesn’t have a built-in Audio Equalizer. Hence, people usually rely on the equalizer in the audio player or a third-party software. The Equalizer APO is one such tool. It is a very popular software among audiophiles, who like to tweak their sound settings. However, there are some users who report about Equalizer APO not working on their system.

Is Equalizer APO not working on your Windows machine? Don’t worry. We are here to help you. First, we will take a look at the basics of Equalizer APO. After that, we will see the reasons why Equalizer is not working. Finally, we will look at some simple troubleshooting solutions that can hopefully fix the issue.

What Is Equalizer APO?

With Windows Vista, Microsoft introduced Audio Processing Objects (APO). It is a software-based digital signal processing (DSP) solution to provide special audio effects.

These “effects” can be equalizers, Automatic Gain Control (AGC), Echo Cancellation, Reverb, etc.

While Windows has a basic set of APOs, it also allows custom APOs from audio hardware manufacturers and third-party developers to enhance the sound experience with additional audio effects.

Jonas Thedering developed the Equalizer APO, a graphical equalizer for Windows in the form of APO (Audio Processing Object). It is an open-source software with several useful features.

Speaking of features, here are some important ones:

  • Low CPU usage
  • Minimal system resources
  • Easy to use GUI
  • Unlimited number of filters
  • Any number of audio channels

There are several more features of the Equalizer APO that you can explore in the official SourceForge link. If you are interested, then we can make a dedicated tutorial or guide on installing and configuring the Equalizer APO.

Is Equalizer APO Not Working?

Coming to the main topic, the Equalizer APO, despite being a simple and open-source software to customize your audio, has some problems. One such problem is that is stops working altogether.

Several users reported about Equalizer APO Not Working on Reddit and even on the official SourceForge comments pages. Are you facing a similar issue? Is the Equalizer APO not working on your system?

Let us quickly explore some common reasons why the Equalizer APO stopped working.

Reasons For Equalizer APO Not Working

  • Incompatibility with Sound Card: If you are using a specialty Sound Card in your system, then the Equalizer APO tries not to mess with the APOs of the sound card and its driver. While this may seem okay, this is one of the main reasons for instabilities in Audio Processing and Equalizer APO not working.
  • Problem with the Installation Mode: You can install the Equalizer APO in three modes. They are LFX/GFX, SFX/MFX, or SFX/EFX. The installation mode that you selected while installing might be not suitable for your system.
  • You Disabled Audio Enhancements: Audio Enhancements are Microsoft’s way of proving some form of customization to its basic audio settings. If you disabled these enhancements, then the Equalizer APO might not work.
  • Antivirus and/or Firewall is Blocking it: Antivirus or Firewall might see some software as a threat and blocks access. If this is the case, then the Equalizer will not work.
  • Using Audio Hardware Acceleration: You might think that using Hardware Acceleration for Audio Enhancement is a good idea. But the CPU offloads the tasks to special hardware (Audio DSP or Sound Card) and cannot read the software APO. As a result, the Equalizer APO might not work properly.
  • Equalizer APO Doesn’t Have Exclusive Control Mode: We have to give third-party software such as Equalizer APO some special permissions for it to work properly. One such permission is enabling “Exclusive Mode” in the sound settings of Windows. If you haven’t enabled them, then there is a good chance that the Equalizer APO will not work at all.
  • Corrupted Configuration Settings File: The important feature of Equalizer APO is the ability to create configuration files and use them with the software. But if these files are corrupted, then Equalizer might not work properly.
  • Problem with Audio Drivers: Any issue with sound drivers in Windows can make Equalizer APO to stop working.

There could be some other reason why Equalizer APO is not working. But the reasons we mentioned here are very common.

How To Fix Equalizer APO Not Working Issue?

Okay. We have seen about Equalizer APO and also some common reasons why it won’t work as expected. But how to fix the issue? Let us now see some simple troubleshooting methods to fix the “Equalizer APO not working” problem.

a. Disable Original APOs

The first solution to fix problems with Equalizer APO is one of the simplest and effective for many users. All you have to do is disable the original APOs (APOs from the sound card driver) and force Equalizer APOs.

This will try to eliminate any instabilities during playback or recording. To do this, open the Configurator and select the audio device.

Now, check the “Troubleshooting options” below. Next, uncheck the “Use original APO” options for both pre-mix and post-mix.

By doing this, we are disabling all the sound card features and APOs and forcing the system to use the Equalizer APO.

b. Enable Audio Enhancements

The next solution is also very popular. All you have to do is to enable audio enhancements in Windows’ Sound Settings.

Open “Settings” in your Windows Machine. Select the “System” tab on the left. Now, go to “Sound”. Scroll down and select “More sound settings”. This will open the Sound Settings Window.

In the “Playback” tab, select the speakers that you want to apply these settings to and then click on “Properties”. In the Speaker Properties window, select the “Enhancements” tab.

Uncheck “Disable all enhancements” option. Also, uncheck the options below this such as “Bass Management”, “Virtual Surround”, “Room Correction”, “Loudness Equalization”, etc. and then click on “OK”.

c. Turn Exclusive Mode On

Open “Settings” in your Windows Machine. Select the “System” tab on the left. Now, go to “Sound”. Scroll down and select “More sound settings”. This will open the Sound Settings Window.

In the “Playback” tab, select the speakers that you want to apply these settings to and then click on “Properties”. In the Speaker Properties window, select the “Advanced” tab.

You can see “Exclusive Mode” below. Check the “Allow applications to take exclusive control of this device” and also the “Give exclusive mode applications priority”.

d. Change The Installation Mode

By default, the Equalizer APO installs in the LFX/GFX Mode. Even the Equalizer APO recommends this mode. If you followed the recommended settings and installed the Equalizer APO in LFX/GFX Mode, then try to install the application in other modes and see if it is working or not.

Open the Configurator and select the speakers or device that you want to apply these changes to. Now, check the “Troubleshooting options” below that.

On the right side, change the mode by selecting “Install as SFX/MFX”. Click on OK and restart the application.

If this is working, then well and good. But if the Equalizer APO is still not working, then you can try to install it in the SFX/EFX mode. Note that even the Equalizer APO mentions this mode as experimental. So, use this mode at your own risk and the result may or may not be in your favor.

e. Reset Equalizer APO

You can reset the Equalizer APO to its default settings and see if its is working or not. Launch the Equalizer APO. Click on “Settings”.

Now click on “Reset all global preferences”. You will get a prompt, click on Yes. This will reset all the settings to default. Close the application and relaunch it.

f. Update Audio Drivers

Press Windows Key and R Key together (Win + R) to open the Run Command. In the run command, type “devmgmt.msc” to open the Device Manager.

Expand the “Sound, video and game controllers” option and right click on the audio device.

Click on “Update Driver”. If there any updates, this will try to update them.

g. Reinstall Audio Drivers

Alternatively, you can uninstall the drivers and reinstall them. you just have to uninstall the drivers from the Device Manager and when you restart the computer, Windows tries to reinstall the drivers for you.

h. Make An Exception For Equalizer APO In Antivirus And/or Firewall

If your Antivirus is the culprit for Equalizer APO not working, then you can simply disconnect the internet, disable the Antivirus and relaunch the Equalizer APO application.

Check and see if Equalizer APO is working or not. If it is working, then you have to add an exception for Equalizer APO in your Antivirus.

Windows Firewall is an excellent security feature for the whole system. It controls what applications can pass through it and what applications cannot pass through it.

Press Windows key and type “Allow”. As soon as you enter this text, you will get a bunch of options and you have to select “Allow an app through Windows Firewall” option.

Click on “Change settings” and from the list of apps, select “Equalizer APO Configuration Editor” and “Configurator.exe”. Select both Private and Public options for these two apps.

Now, restart the Equalizer APO and see if it is working or not.

i. Uninstall And Reinstall Equalizer APO

We are getting desperate here. You can uninstall the Equalizer APO from your Windows System and reinstall it. If there was a problem with the previous installation, this will solve the issue.

j. Disable Hardware Acceleration For Audio

If you are using any sort of Hardware Acceleration for Audio, then disable this and see. When we enable Audio Hardware Acceleration, all the audio related tasks are offloaded to a special DSP or Sound Card.

The CPU is essentially not in a position to recognize the Equalizer APO (which is a CPU based Sound Configuration). So, even if you are making any changes in the Equalizer APO, it will not work. Completely disable all Audio Hardware Acceleration options.

There are other solutions which involve tweaking the Windows Registry. This is an extreme approach and we thought messing with Registry files may not be ideal.


Equalizer APO is a very popular graphical equalizer for Windows Operating System. For those who are fed up with the lack of audio enhancements and customizations in Windows, the Equalizer APO is an excellent application.

It is a very lightweight application and the best thing is it is open-source. But sometimes, the Equalizer APO doesn’t work as expected or doesn’t work at all.

In this guide, we saw the basics of Equalizer APO. After that, we saw some common reasons for why Equalizer APO might not work on your system.

Finally, we also saw few troubleshooting solutions to fix the “Equalizer APO Not Working” problem. If you feel that we might have missed something important, please mention it in the comments section. It will be helpful to us as well as other readers.

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