New digital signal processing functionalities such as ''Room Correction'', ''Bass Management'', ''Loudness Equalization'' and ''Speaker Fill'' have been introduced. ''SpeakerThese Fill''adapt mixesand 2-channelmodify content to use all available speakers in a manner similar to [[Creative Technology|Creative's]] [[Sound Blaster X-Fi#CMSS-3D|CMSS]]. ''Bass Management'' can be used to redirect thean subwooferaudio signal to the main speakers. If a channel is missing, a feature called ''Channel Phantoming'' allows thetake best useadvantage of the speakers that are there, by redirecting the sound of the missing channels through these speakers. Whether therespeaker isconfiguration a multi-channel or stereo soundgiven system in a home theater or living room,has. Windows Vista also includes the ability to calibrate the speakers for that room. By placing a microphone where the listener plans to sit and then running a wizard that measures thegiven room's response, Windows Vista canacoustics 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 newsoftware feature called ''Headphone Virtualization'', which uses technology based upon a [[Head-related transfer function]]wizard.<ref name="AudioImprovements">{{cite web |url=http://windowsvistablog.com/blogs/windowsvista/archive/2006/12/06/audio-improvements-in-windows-vista.aspx |title=Audio Improvements in Windows Vista |last=Allchin |first=Jim |author-link=Jim Allchin |date=December 6, 2006 |publisher=[[Microsoft]] |work=Windows Vista Team Blog |archive-url=https://web.archive.org/web/20061209135853/http://windowsvistablog.com/blogs/windowsvista/archive/2006/12/06/audio-improvements-in-windows-vista.aspx |archive-date=December 9, 2006 |access-date=November 3, 2015}}</ref>
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. These effects are packaged as user-mode System Effect Audio Processing Objects (sAPOs).<ref>{{Cite web |url=http://www.microsoft.com/whdc/device/audio/sysfx.mspx |title=Custom Audio Effects in Windows Vista |access-date=2007-09-06 |archive-date=2007-08-09 |archive-url=https://web.archive.org/web/20070809132956/http://www.microsoft.com/whdc/device/audio/sysfx.mspx |url-status=live }}</ref> These sAPOs are also reusable by third-party software.
