A scientific article I stumbled upon scanned subject’s brains using fMRI whilst they listened to voices being played over headphones. The voices were either played in stereo (inside the head) or using 3D audio (outside the head). The aim was to find the neural substrate for the perception of voices outside the head (in what we might call external auditory space) in an effort to better understand auditory hallucinations of that type. You can find the article for free here. Very interesting.

One other large emerging application of 3D audio that you might not be aware of is for hearing aids. People who require hearing aids at the moment have sounds simply amplified and they are unable to know the direction of where the sounds came from. This makes situations such as a dinner party almost impossible. Normal listeners at a dinner party are able to follow one conversation and ignore the other voices due largely to the fact that the brain knows where the sounds are coming from (this is the so-called Cocktail Phenomenon). Once this ability is lost, as with a hearing aid, all the voices are mashed together and it is impossible to follow a conversation. A hearing aid with 3D audio amplifies the sounds around the listener and at the same time provides a sense of where the sounds are coming from.

Have a listen to this demo (USING HEADPHONES ONLY) to see what it is like have a hearing aid with and without 3D audio. The demo starts without 3D audio and then 30 seconds in it switches to 3D audio, you will hear it don’t worry (think of what it’s like to have hallucinations of people talking while you listen). Focus on trying to understand the different talkers. Again, you must use headphones:

The aim of the first stage of the project has been to predict where in this space you the listener would be. We are in the process of refining a tool that will be able to predict your position in this space based on a few key morphological parameters (mainly related to the size of your ear). Once your position has been calculated we can then choose the closest neighbour (best set of ears) that is best suited for you. Have a listen here (or click on ‘Project Demo’ at the top of the page) to experience what it is like to listen with another person’s ears. See which set of ears you like more: the red, green or purple?

People Space

Is 3D here to stay? Could 3D audio be the next technology production companies roll out in order to lure customers back to cinemas and away from free downloads over the internet?

A recent article in The New York Times has suggested that the estimated $58.2 million in tickets at North American theatres over the opening weekend of ‘Monsters vs. Aliens’ “indicates that 3-D is the story”. The article goes on to say that a very significant number of theatres are being equipped for future 3D releases suggesting that the movie format could be here to stay this time.

Given the success of ‘Monsters vs. Aliens’ and the willingness of audiences to wear 3D glasses, could it be imaginable that they would be happy to wear headphones at the movies for a 3D audio effect? Using headphones at the cinema would allow for the ultimate surround sound experience, given that speakers can only create a convincing effect for a small number of seats in the cinema at the so-called ‘sweet spot‘. Movies could also be played in many different languages at the same time.

It’s an interesting concept, only time will tell.

What is interesting about Microsoft’s vision is the focus on tactile technologies, and in particular augmented and virtual reality. This is particularly relevant for the ‘listen with your own ears’ project (see About) given that the technology is all about creating a personalised virtual audio environment. Thus it could be used to compliment the technologies of the future in a big way.

Have a look at the montage and see what you think.

Visit the site and watch the short movie (or watch it below) for some amazing audio effects. Remember to wear your headphones.

Enjoy

The GSMA Mobile World Congress (formerly 3GSM World Congress) represents the world’s largest exhibition for the mobile industry with a stimulating and insightful congress that brings together prominent leaders and personalities from mobile operators and equipment vendors, as well as Internet and entertainment professionals. Arkamys will have a stand at the GSMA Mobile World Congress showing off its latest technology from the 16th to the 19th of February. http://www.mobileworldcongress.com/overview.shtml

It is an example of what is called a ‘binaural recording‘. A dummy head, with tiny microphones stuck inside its ears, is used to record an acoustic environment such as a person cutting your hair or a band playing in a room. You then listen to the binaural recording over headphones and it is as if you were sitting at the position of the dummy head at the moment of the recording. The best way to really understand the process is to just watch and listen to these examples:

YOU MUST USE HEADPHONES FOR THE FIRST EXAMPLE!

‘Snakecharmer-Binaural‘ by Ottmar Liebert

John Q. Walker’s talk (7 minutes 45 seconds in) entitled ‘Re-creating great performances’ from the EG 2007 conference posted on TED

Don’t forget to subscribe to the blog’s RSS feed on the home page to get updates on all the latest posts and demos.

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Here is a very accessible scientific journal article explaining how the shape of your own ear is unique and how this determines your perception of the sounds you hear around you everyday. And can you adapt to new ear shapes, or learn to listen with someone else’s ears?

If the journal article was not convincing enough, have a look at this 1998 BBC report on how a murderer was caught using his earprint…

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The photos are currently offline for this post. They will be back very soon!

Below is a run-down of the process normally involved, which makes the technology difficult to commercialize in its current form. Thus the push for a viable method in the current ‘listen with your own ears’ project in which a personalized 3D audio will be generated from a simple photo of the person’s head and ear.

A sound proof anechoic (no echoes) chamber is needed first.

Then tiny microphones are placed into my ears.

I am then seated in the middle of the chamber with the microphones inside my ears, and a head tracker on my head to let us know the position of my head at all times. Then sounds are played consecutively out of the three small speakers seen in the above photo on the robotic arm. The sounds are recorded with the small microphones in my ears. Then I am rotated around say 15 degrees on the chair and the sounds from the speakers are again played and recorded. This process continues for a full rotation, and then the robotic arm rises up a few degrees and a new rotation begins. This way the sound from the speakers is recorded from many positions on an imaginary sphere around my head.

The recorded signals taken from the microphones for the many positions around my head are then stored on a computer. Using these recordings we can see how my own ears filter sounds for each position in space. Using this information we can then take any audio stimulus and synthesize it so that when I listen to it over headphones I will get the impression that the sound is coming from one of the recorded positions in space. I will at this stage have a personalized 3D audio.

Thanks to Jack for the shots.

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