Editing Head-related transfer function (section)

== Recording and playback technology ==
Recordings processed via an HRTF, such as in a computer gaming environment (see [[A3D]], [[Environmental audio extensions|EAX]], and [[OpenAL]]), which approximates the HRTF of the listener, can be heard through stereo headphones or speakers and interpreted as if they comprise sounds coming from all directions, rather than just two points on either side of the head. The perceived accuracy of the result depends on how closely the HRTF data set matches the characteristics of one's own ears, though a generic HRTF may be preferred to an accurate one measured from one's one ear.<ref>{{cite journal |last1=Armstrong |first1=Cal |last2=Thresh |first2=Lewis |last3=Murphy |first3=Damian |last4=Kearney |first4=Gavin |title=A Perceptual Evaluation of Individual and Non-Individual HRTFs: A Case Study of the SADIE II Database |journal=Applied Sciences |date=23 October 2018 |volume=8 |issue=11 |pages=2029 |doi=10.3390/app8112029|doi-access=free }}</ref> Some vendors like Apple and Sony offer a variety of HRTFs to be selected by the user's ear shape.<ref>{{cite web |title=Spatial Audio: Part 1 - Current Formats & The Rise Of HRTF - The Broadcast Bridge - Connecting IT to Broadcast |url=https://www.thebroadcastbridge.com/content/entry/19051/spatial-audio-part-1-current-formats-the-rise-of-hrtf |website=The Broadcast Bridge |language=en |date=7 December 2022}}</ref>

[[Windows 10]] and above come with [[Microsoft Spatial Sound]] included, the same spatial audio framework used on [[Xbox One]] and [[Hololens 2]]. On a Windows PC or an Xbox One, the framework can use several different downstream audio processors, including [[Windows Sonic for Headphones]], [[Dolby Atmos]], and [[DTS Headphone:X]], to apply an HRTF. The framework can render both fixed-position [[surround sound]] sources and dynamic "object" sources that can move in space.<ref>{{cite web |title=Spatial Sound for app developers for Windows, Xbox, and Hololens 2 - Win32 apps |url=https://learn.microsoft.com/en-us/windows/win32/coreaudio/spatial-sound |website=learn.microsoft.com |date=27 April 2023 |language=en-us}}</ref>

Apple similarly has Spatial Sound for its devices used with headphones produced by Apple or Beats. For music playback to headphones, Dolby Atmos can be enabled and the HRTF applied.<ref>{{cite web |title=About Spatial Audio with Dolby Atmos in Apple Music |url=https://support.apple.com/en-hk/HT212182 |website=Apple Support |date=27 March 2023 |language=en}}</ref> The HRTF (or rather, the object positions) can vary with [[head tracking]] to maintain the illusion of direction.<ref>{{cite web |title=Listen with spatial audio for AirPods and Beats |url=https://support.apple.com/en-hk/HT211775 |website=Apple Support |date=19 July 2023 |language=en}}</ref> [[Qualcomm Snapdragon]] has a similar head-tracked spatial audio system, used by some brands of Android phones.<ref>{{cite web |title=Spatial Audio |url=https://www.qualcomm.com/products/features/snapdragon-sound/spatial-audio |website=www.qualcomm.com |language=en}}</ref> [[YouTube]] uses head-tracked HRTF with 360-degree and VR videos.<ref>{{cite web |title=Use spatial audio in 360-degree and VR videos - YouTube Help |url=https://support.google.com/youtube/answer/6395969?hl=en-GB |website=support.google.com}}</ref>

Linux is currently unable to directly process any of the proprietary spatial audio (surround plus dynamic objects) formats. SoundScape Renderer offers directional synthesis.<ref>{{cite web |title=SoundScape Renderer |url=http://spatialaudio.net/ssr/ |website=spatialaudio.net |date=9 January 2013}}</ref> [[PulseAudio]] and [[PipeWire]] each can provide [[virtual surround]] (fixed-location channels) using an HRTF. Recent PipeWire versions are also able to provide dynamic spatial rendering using HRTFs,<ref>{{cite web |title=Filter Chain |url=https://gitlab.freedesktop.org/pipewire/pipewire/-/wikis/Filter-Chain#virtual-surround |website=gitlab.freedesktop.org/pipewire/pipewire |date=14 April 2023 |language=en}}</ref> however integration with applications is still in progress. Users can configure their own positional and dynamic sound sources, as well as simulate a surround speaker setup using existing configurations.

The cross-platform OpenAL Soft, an implementation of [[OpenAL]], uses HRTFs for improved localization.<ref>{{cite web |title=OpenAL Soft - Software 3D Audio |url=https://openal-soft.org/index.html |website=openal-soft.org}}</ref>

Windows and Linux spatial audio systems support any model of stereo headphones, while Apple only allows spatial audio to be used with Apple or [[Beats Electronics|Beats]]-branded Bluetooth headsets.{{Citation needed|date=February 2023}}