A. This is a known problem that occurs when your Intel Mobile Pentium III processor uses Intel SpeedStep technology. SpeedStep requires that the processor restart and have its attributes modified several times a second. For good playback, the USB sound system relies on a data stream that reaches coders-decoders (codecs) at a steady rate. The problem occurs because the two processes conflict, disrupting the data stream. This disruption causes audio distortion, such as a popping or crackling noise.

To resolve the hissing problem, disable the SpeedStep functionality as follows:

  1. Start the Control Panel Power Options applet (go to Start, Settings, Control Panel, and select Power Options).
  2. Select the Power Schemes tab.
  3. Under "Power schemes" select Always On.