The levels are expressed as DWORDs that represent the default kernel streaming (KS) decibel levels that the class driver should return. To specify a custom audio volume level or microphone boost level, use the wrapper INF file to specify custom levels per pin complex ID. The pin complexes represent the physical connectors for the associated device (e.g. Note that there are IDs for the individual nodes, as well as IDs for the pin complexes. The following diagram which shows a sample HD Audio codec topology. The mechanism for overriding the Audio Class driver’s hard-coded values involves writing an INF file that wraps the Audio Class driver’s inbox INF file (hdaudio.inf), and using this wrapper INF to specify the desired values. The Audio Class driver has been redesigned to allow you to override the hard-coded default values. And one of the most important settings to adjust is the volume level, as users are sensitive to the loudness or quietness of their audio systems, especially during first-time use. As such, OEMs are not able to override these values to meet their own requirements. The HD Audio class function driver, which I shall now refer to as the Audio Class driver, uses various hard-coded default values that cannot be customized for any particular PC. Note The process described here can only be used if the default Microsoft HD Audio driver is being used.īy default, the HD Audio class function driver sets the audio volume and the microphone boost levels at predetermined values to ensure a pleasant “out of the box” experience for the user. The ability to customize the in box HD audio default audio volume and microphone boost levels to suit a specific PC, provides OEMs with some flexibility in their audio adapter installation parameters. Customizing HD Audio Driver Volume Settings