IAudioBass interface

The IAudioBass interface provides access to a hardware bass-level control. The client obtains a reference to the IAudioBass interface of a subunit by calling the IPart::Activate method with parameter refiid set to REFIID IID_IAudioBass. The call to IPart::Activate succeeds only if the subunit supports the IAudioBass interface. Only a subunit object that represents a hardware function for controlling the level of the bass frequencies in each channel will support this interface.


The IAudioBass interface inherits from IPerChannelDbLevel but does not have additional members.

The IAudioBass interface provides per-channel controls for setting and getting the gain or attenuation level of the bass frequencies in the audio stream. If a bass-level hardware control can only attenuate the channels in the audio stream, then the maximum bass level for any channel is 0 dB. If a bass-level control can provide gain (amplification), then the maximum bass level is greater than 0 dB.

Most Windows audio adapter drivers support the Windows Driver Model (WDM) and use kernel-streaming (KS) properties to represent the hardware control parameters in subunits (referred to as KS nodes). The IAudioBass interface provides convenient access to the KSPROPERTY_AUDIO_BASS property of a subunit that has a subtype GUID value of KSNODETYPE_TONE. To obtain the subtype GUID of a subunit, call the IPart::GetSubType method. For more information about KS properties and KS node types, see the Windows DDK documentation.


Minimum supported client

Windows Vista [desktop apps only]

Minimum supported server

Windows Server 2008 [desktop apps only]



See also

Core Audio Interfaces
DeviceTopology API
IPerChannelDbLevel Interface