 Then the streams are mixed by the global audio engine, where a set of "global audio effects" (GFX) may be applied.Finally, they're rendered on the audio device.The higher level APIs such as the Waveform-Audio Interface (waveXxx functions) and DirectSound use shared mode, which results in pre-mixed PCM audio that is sent to the driver in a single format (in terms of sample rate, bit depth and channel count).