The Crystal WDM Audio Codec is a type of audio driver for audio chips produced by Crystal Semiconductor (later acquired by Cirrus Logic). The WDM (Windows Driver Model) version of the codec is a software interface that allows the operating system (Windows) to communicate with the audio hardware for tasks like playing sound, recording audio, and managing input/output (I/O) channels for audio devices.

The Crystal WDM Audio Codec Windows driver is necessary to enable audio functionality on a computer that uses a Crystal Semiconductor (or Cirrus Logic) sound chip. Without this driver, Windows may not be able to detect or use the audio hardware properly.