Spatial audio; binaural audio

Spatial audio is the umbrella for placing sounds around, above, and below a listener instead of only between left and right speakers. Binaural audio is one headphone-ready way to deliver it: an HRTF, or head-related transfer function, filters each ear differently to mimic the timing and tone changes caused by a real head and outer ears.

Reach for it in games, VR, guided experiences, and immersive music. A Dolby Atmos mix can position channels and audio objects in a 3D scene, then a binaural renderer turns that scene into an ordinary two-channel headphone signal. Unlike a simple stereo pan, HRTF processing can suggest front, back, height, and distance as well as left and right. The Virtual Barber Shop clip is where most people first hear it work, and Apple's Spatial Audio adds head tracking on AirPods so the scene stays put when you turn your head.

Gotcha: binaural placement is built for headphones, and one generic HRTF does not fit every person's ears, so front and back can swap or height can feel vague. Head tracking helps by keeping the scene fixed while the listener moves. Always test on headphones, speakers, and mono; phase-heavy spatial tricks can collapse badly outside the intended playback setup.