HRTF, or Head-Related Transfer Function, adds 3D "spatial sound" to the Rift's array of features – enabling the headset to simulate the position of sounds in 3D space, and alter the sound to reflect your head movements. Although HRTF technology has existed for decades, the Rift takes advantage of its more accurate head-tracking technology to improve the fidelity of the 3D audio.
We stopped by Oculus VR's booth at CES to try out the latest version of Crescent Bay and its HRTF feature – and it certainly sounds impressive. We're ushered into a soundproof room and try on the latest iteration of the Rift headset – which is surprisingly lightweight, despite its size, and features on-ear headphones that fold into place over your lugholes.
The short demo that Oculus has chosen to showcase HRTF doesn't feature interactive gameplay – but it's impressive all the same. Kicking off with a scene set aboard a submarine, you can hear whistling steam from cracked pipes that shifts position as you turn your head. Another demo features a dinosaur growling and glowering at you; move in close and crane your head, and you can hear its breathing. A woodland scene with stylised, polygonal animals features rustling leaves and twittering birds that fly around your head, while another scenario presents you with a friendly alien that burbles at you as you approach; in the background, its spaceship can be heard humming away to itself.
Throughout the demo, what impresses most is how natural it all seems; the soundscape shifts around you as you move your head, and even small movements let you register changes in pitch and Doppler shifts, adding to the sense of scale and immersion. Particularly impressive is a sequence featuring a tiny living model of a city; firefighters tackle a blaze while cars and helicopters flit about. Lean in close, and you can precisely identify the location of different sounds, from crackling fires to whirring rotor blades.
The visual spectacle is impressive, too; though there's still a visible pixel grid in the display, it's much finer than that of the early prototype Rift devices – and the wide field of view plunges you into the action and helps to create a sense of scale. A sequence in which you perch atop a skyscraper like Batman induces wobbly-kneed feelings of vertigo, while a Jurassic Park-style scene in which you're menaced by a massive T-Rex produces an atavistic fight-or-flight response. We can only imagine the fun that game developers are going to have, giving us the screaming heebie-jeebies.
The demo reel culminates in Epic Games' Unreal-powered Showdown – an action sequence that gives you an idea of the device's gaming potential. You're plunged into the midst of a pitched battle between soldiers and a giant robot on a city street; shards of glass and shrapnel fly past in slow motion, and as you peer in close you can see the reflections of explosions in the puddles on the ground. Gunfire and explosion sounds are placed precicely in the 3D space, and we can certainly see how the HRTF technology will give FPS players an edge in combat.
If there's one problem with the Crescent Bay prototype, it's that the headphones feel a little flimsy, like the complimentary on-ears you get on an aeroplane. We'd like to see a more substantial set of cans, perhaps with noise isolation, in the final product; and a slightly higher-resolution display wouldn't go amiss too.
Despite those caveats, the Rift is undoubtedly impressive; frankly, they could release it in its current state, but founder Palmer Luckey clearly feels there's more work to do on it.
READ MORE: All the latest news from CES 2015