Microsoft DirectX 9.0

Adjusting DirectSound Acceleration for Testing

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:


Enables complete DirectSound acceleration, including the enabling of IKsPropertySet extensions.


Enables acceleration of DirectSound secondary buffers, but disables any hardware-specific IKsPropertySet extensions. This is the default setting on Windows 2000.


Disables hardware acceleration of DirectSound secondary buffers. This option is useful if you want to emulate a nonaccelerated sound card for testing purposes.


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.