Equalizer APO is a parametric / graphic equalizer for Windows. It is implemented as an Audio Processing Object (APO) for the system effect infrastructure introduced with Windows Vista.


  • Virtually unlimited number of filters
  • Works on any number of channels
  • Very low latency, which makes it suited for interactive applications
  • Low CPU usage
  • Modular graphical user interface
  • VST plugin support
  • Integrates into Voicemeeter

What's New

  • Fixed: Bluetooth devices on Windows 11 often did not work when multiple devices were combined (headphones and hands-free). In this case, installation as SFX/MFX is now used by default as EFX does not work.
  • Fixed: Reimplemented Voicemeeter integration (based on official examples) to fix stuttering issues.
  • Improved: On Windows 8.1 and newer, installation as SFX/EFX is now the default. This should remove the need to use the troubleshooting options for most users.
  • Improved: Updated to Visual Studio 2019 and Qt 5.15.2. Running Equalizer APO requires Universal CRT now, which means that Windows versions before 10 may need additional Windows updates or the Visual C++ Redistributable for Visual Studio 2015 - 2019 needs to be installed (installer provides assistance).


  • Windows Vista or later (currently only Windows 7, 8, 8.1, 10 and 11 have been tested)
  • The application must not bypass the system effect infrastructure (APIs like ASIO or WASAPI exclusive mode can not be used)