Adjusting DirectSound Acceleration for Testing

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[The feature associated with this page, DirectSound, is a legacy feature. It has been superseded by WASAPI and Audio Graphs. Media Casting have been optimized for Windows 10 and Windows 11. Microsoft strongly recommends that new code use Media Casting instead of DirectSound, when possible. Microsoft suggests that existing code that uses the legacy APIs be rewritten to use the new APIs if possible.]

By using the Sounds and Audio Devices page in Control Panel, you can adjust the performance of DirectSound on the system. Click the Advanced button in the Sound Playback group on the Audio tab. In the Advanced Audio Properties dialog box, choose the Performance tab. A slider lets you adjust hardware acceleration to one of the following settings:

  • Full
    Enables complete DirectSound acceleration, including the enabling of IKsPropertySet extensions.
  • Standard
    Enables acceleration of DirectSound secondary buffers, but disables any hardware-specific IKsPropertySet extensions. This is the default setting on Windows�2000.
  • Basic
    Disables hardware acceleration of DirectSound secondary buffers. This option is useful if you want to emulate a nonaccelerated sound card for testing purposes.
  • Emulation
    Forces DirectSound into emulation mode, where it acts as if there is no DirectSound-compatible driver on the system. All mixing is done by DirectSound in user mode, and the resulting data is sent to the Win32 waveform-audio functions. This typically results in a large increase in latency.