 By placing a microphone where the listener plans to sit and then running a wizard that measures the room response, Windows Vista can automatically set the levels, delay and frequency balance for each channel accordingly for this position.For PCs equipped with stereo headphones, Vista adds the ability to have surround sound using a new feature called "Headphone Virtualization", which uses technology based upon a Head-related transfer function.Windows Vista also includes the ability to use custom host-based digital signal processing effects as part of the audio device manufacturer-supplied driver's value-added features.