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ISpVoice::SetVolume (SAPI 5.4)

Microsoft Speech API 5.4


ISpVoice::SetVolume sets the synthesizer output volume level of the voice in real time. The default base volume for all voices is 100.

    HRESULT SetVolume(
   USHORT 	usVolume


  • usVolume
    [in] Value containing the requested volume level. Volume levels are specified in percentage values ranging from zero to 100 - values outside this range may be truncated.

Return values



SetVolume affects the volume of synthesized WAV data; it does not affect the volume of the .WAV file that is played back. Volume is specified as a percentage of the maximum volume of the current voice. Different voices may have different maximum volume levels.

Applications can adjust the volume of a voice either through this function call, or through XML grammar passed to the voice with the input text of a speak call (see the XML Schema : SAPI white paper). The voice should combine volume adjustments made in these two ways to arrive at a final volume.