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Consider the following scenario:

  • You have a Windows 8-based computer that has a speaker and a microphone attached.

  • You set the speaker as the default device, and you enable the Room Correction feature.

  • You restart the computer. Or, you restart the Windows Audio service.

  • You run a Windows Audio Session API (WASAPI) loopback recording application to start recording in loopback mode on the default device.

  • You play an audio file in Windows Media Player.

In this scenario, the Room Correction feature is not enabled when you play the audio file. Specifically, the later rendering on the default device does not load the GFX APO system effects.


This issue occurs because some variables are not initialized correctly when the system uses a WASAPI application to perform loopback recording on the default device.


Update information

To resolve this issue, install update rollup 2855336. For more information about how to obtain this update rollup package, click the following article number to view the article in the Microsoft Knowledge Base:

2855336 Windows RT, Windows 8, and Windows Server 2012 update rollup: July 2013


Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

More Information

For more information about WASAPI, go to the following Microsoft website:

General information about WASAPIFor more information about loopback recording, go to the following Microsoft website:

General information about loopback recordingFor more information about software update terminology, click the following article number to go to the article in the Microsoft Knowledge Base:

824684 Description of the standard terminology that is used to describe Microsoft software updates

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