sAPO Bypass
After the endpoints and endpoint property stores have been created, the audio service builds the audio device graph that handles the signal processing. The endpoint property store has a global effects bypass setting, PKEY_Endpoint_Disable_SysFx, which enables or disables system effects. A check box on the Audio Control Panel item allows the user to set this property. By default, system effects are disabled. If system effects are enabled and LFX or GFX sAPOs are associated with the device, the audio service adds them to the graph along with the standard audio sAPOs.
The audio service registers for property store notifications so it can monitor changes in the GFX and LFX settings as well as changes in the effects bypass setting. If the audio service receives a notification, it signals a configuration change to all associated audio servers. From that point, the operation proceeds as it does for device format changes.
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