Every Headphone Surround Virtualization on your Sound Card!

Using audio processing objects (APOs) in Windows is possible since Vista. Those provide customizable, software-based digital signal processing (DSP). A freeware called Equalizer APO makes use of that infrastructure and allows to real-time-convolve 7.1 input sounds down to binaural stereo audio for headphones. This tool works nealy without using any CPU power, latency free and the kind of convolution you want to use is customizable. I have currently recorded or collected impulse responses of:

  • Dolby Atmos Headphone
  • CMSS-3D
  • SBX Pro Studio Surround (formerly THX TruStudio Pro Surround)
  • Dolby Headphone
  • Sennheiser GSX Binaural 7.1
  • DTS Headphone:X
  • Windows Sonic Headphone
  • Dolby Home Theater v4 Headphone Surround Virtualizer
  • Razer Surround
  • Out Of Your Head


  1. Download Equalizer APO.
  2. The program will ask you to configure your playback device. Tick the box in front of the port where your headphones are connected to and finalize the installation. (But do not reboot.)
  3. Instead of rebooting, press Win+R and paste the following into the opened window:powershell -Command "Start-Process cmd -ArgumentList '/c "net stop Audiosrv && net start Audiosrv && mmsys.cpl"' -Verb RunAs
  4. The sound preferences should open soon. First click on your device, then onto the lower right Properties button of the previous window and change Advanced – Default Format to 48000Hz. Save with OK.
  5. Click on Configure in the lower left of the previous window. Select 7.1 Surround and continue till the window closes. (Skip to the last step if you could select 7.1 or continue with 5a if it didn’t work [e.g. with some DACs or DP/HDMI audio].)

    5a. Download and install Voicemeeter, reboot.

    5b. Open Virtual IO Control Panel from your start menu and click Options – Internal Sampling Rate: 48000Hz. Open Voicemeeter and also select 48000Hz in Menu – System settings / Options – Preferred Main SampleRate.

    5c. Open mmsys.cpl again (that’s the sound preferences window from step 4) and change Advanced – Default Format to 48000Hz in the Properties of VoiceMeeter Input window. Open also the preferences of your speakers and tick both boxes below Advanced – Exclusive Mode. Reboot again.

    5d. Open EQ APOs Configurator.exe, select Output A1 and remove the cross you made earlier. Redo step 3.

    5e. Launch Voicemeeter and select your output device as Hardware Out – WDM: Speaker (Soundcard). Mark Menu – Hook Volume Keys (For Level Output A1) and Menu – System Tray (Run at Startup). You can now safely close this window.

  6. Download this archive and extract it into %ProgramFiles%\EqualizerAPO\config (a file called config.txt should be overwritten). Now you are ready to go!

Simply changing between stereo and 7.1 in Windows will de- and reactivate the sound processing. You can use a different virtualization by replacing hrir\atmos.wav in line 5 of the config.txt with something else from the hrir folder (change everything to 44100Hz when using ciair.wavirc.wav or mit.wav).

You can of course create filters and more stuff for your audio output, simply check out EQ APOs configuration reference or play around with its Editor.exe.

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