WTF is an HRTF?

Cory Martin
HEAR360
Published in
3 min readOct 19, 2016

WTF is an HRTF? That’s what our moms asked us when we told them we had created software that was about to become a game changer in the world of sound. So, we broke it down for them and we’re posting it here, just in case you want to wow your next bunko group with some high tech knowledge.

HRTF stands for head related transfer function. What does that mean?

Well, let’s first back it up a beat and get into how you hear. You see, even though we have two ears our reptilian brain has evolved to hear in 3D. Being able to hear in 3D is critical to how we survive. It’s allowed us to hunt, sense danger, find a mate, socialize and, of course, hear the pop of a champagne bottle from across the room.

If champagne isn’t your thing, that’s cool, because you might hear the crinkle of a chip bag instead. You see we all hear the world differently. That’s because no two human heads are alike and the distance between our ears, the density of our noggins and the shape of our pinna (the Dumbo flaps on our ears) are all unique. Our personal 3D sound systems work specifically for our individual experiences. Which is great in the wild, not so great when you’re Netflix and chillin’ with your iPad or ignoring the manspreading dude on the subway while you watch the latest X-Men.

Major motion pictures are mixed for theaters, not mobile devices. The sound designers and engineers can position sound above, behind, in front and to the left and right of an audience. That’s what makes it sound so immersive. BUT when that same movie is played on a mobile device through headphones the sound falls flat.

This is where HRTF comes into play. It’s a filter set that takes recorded or synthesized sound and allows it to be played back in three dimensions through headphones. No more boring, 2D sound, now you can hear sound just like you hear it in the real world or in a theatre. But not quite, because as we said everyone hears differently, so an HRTF that sounds good to you might sound awful to me.

Some companies like OSSIC are trying to solve this at the hardware level by using sensors to calibrate the sound of your headphones specifically to you — with a few simple inputs an HRTF that is closest to your hearing can be selected. BUT even that doesn’t always work, and that’s why HEAR360 has a different approach entirely.

We’ve developed H360Core, a proprietary HRTF that sounds great no matter what shape, size, or density your head may be. By running AC3 or PCM audio output through H360 Core, we are able to recreate not only a front and back, but also a height channel for ANY professionally 3D mixed music, movie or video game. The audio can be pre-encoded into the stream, processed on the client side of mobile apps, or embedded into chips for use in gaming headphones. We call this H360+ (HPS or iHS).

If you didn’t understand all that tech talk, don’t worry all you need to know is that H360+ is about to revolutionize the world of sound.

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