Head Related Transfer Functions (HRTF)
Locating sounds in 3D with your headphones

A human being hears the position of sounds. He can distinguish left and right, front and back, and up and down. But how do you hear spatially?

History

Back in the ‘70’s, “dummy head” microphones were used to create spatial audio recordings. With headphones, one was able to listen to those recordings and marvel at the impressive spatial distribution of sounds – just like in real life.

Use Headphones

Nowadays, we have a much better understanding of the human binaural perception and we can even simulate spatial audio signals with the help of computers. Indeed, a modern virtual reality (VR) headset such as the Oculus Rift or Samsung Gear utilizes 3D audio to allow a scene viewed in 3D also to be heard in 3D, with unbelievably realistic results.

For example, using headphones, listen to this example of spatial audio:

Why are the ears important for hearing spatially?

The shape of your ears is important. Depending on the direction of the sound, the coloraration of the sound is different and your brain can instinctively map this frequency filtering to a position.

In headphone based spatial audio system, the effect is simulated by a so called Head-Related-Transfer function (HRTF). The main problem is however that the human ears differ as much as finger prints. Thus, also the HRTFs differ from human to human.

The Effect of a HRTF

Part of the magic of a good 3D audio reproduction involves the so-called, “head-related transfer functions” (HRTFs). HRTFs describe the unique pattern of how acoustic waves propagate to a listener’s ear drums, being acoustically filtered by the listener’s ears, head, and torso on the way. When working with dislocated sound sources, the human binaural hearing helps us to better analyze the environment. This relates to the process by which the brain can filter out a specific direction from a mix of acoustic events.

Each Ear is Different

HRTFs create a problem because human ears differ from listener to listener as much as human fingerprints do. Instead of presenting personalized HRTFs for each of us, generic HRTFs are usually used in VR headsets. Such generic HRTFs might work well, or not, depending on their similarity to a listener’s individualized HRTFs

Get your Personalized HRFT

using free MySofa web service.

MySofa helps you to find the HRTF which suits your hearing best.

MySofa needs information about the size of your head and the form of your ears. Then, we calculate a HRTF which is a first suggestion. By listening to 3D audio sound, you need to tune the HRTF. Finally, you can view and download your HRTF. It comes in the AES SOFA file format.

1. step

Register and login

at https://mysofa.audio/login.html

2. step

Tell us about the size of your ears and head

measure manully or scan your head in 3D

3. step

We calculate your personalized HRTF

based on your preferences

4. step

Listen to your HRTF

to hear whether you like it

5. step

Download your SOFA file

and use it in your favorite apps