A technological playground of 64 loudspeakers

Friday 15 Jan 16


Marton Marschall
Senior Officer
DTU Health Tech


Torsten Dau
Head of Sections, Professor
DTU Health Tech
+45 45 25 39 77
For Marton Marschall, a postdoctoral researcher at the Technical University of Denmark (DTU) in Copenhagen, the department of Electrical Engineering’s new audio-visual immersion lab (AVIL) is “a great technological playground” where he and fellow engineers from academia and industry can probe the mysteries of human hearing. KEF, the company who provided the loudspeakers, has produced a video about the new laboratory.

A collaboration between the university and three Danish hearing-aid companies, the state-of-the-art facility creates realistic soundscapes in order to investigate spatial hearing in challenging conditions.
In designing the laboratory, KEF LS50 speakers were employed for the central 64-point sphere.
“We were looking for a compact studio monitor with a concentric design, and that has two advantages from our perspective,” says Marton Marschall.
“One is that the loudspeakers appear more like point sources when viewed from the centre, and that’s nice from a theoretical perspective for sound-field reproduction applications. Secondly, when you are in a sphere like this you have loudspeakers all around you, so it is important that the characteristics of the loudspeakers don’t change, which was one of the advantages of the concentric design,”
he says and then adds with a smile:
“In a way it’s a great technological playground, so who wouldn’t like to play around with 64 loudspeakers.”
Essentially a soundproofed anechoic chamber, the AVIL is a virtual environment that recreates complicated “sound scenes”, such as a rowdy restaurant or a crowded railway station. This is achieved with 64 loudspeakers that are arranged in the shape of a sphere, thereby surrounding a listener. The speakers are not only positioned above and around the listener, but also below the laboratory’s suspended floor. Ultimately, experiments performed in the laboratory could have profound impact on the quality of countless lives around the world, while also educating young engineers and preparing them for careers in industry. It is anticipated that the AVIL will contribute to improvements to hearing aids, cochlear implants and speech-recognition technology, the diagnosis of hearing-impairment conditions, and even to the design of school classrooms to maximize speech intelligibility when young children are learning.
According to Head of Hearing Systems Torsten Dau, about 10 per cent of the adult population worldwide currently has hearing difficulties, and it is predicted that perhaps 100 million people will suffer moderate to severe hearing loss by 2025. Torsten Dau adds that while experiments have been undertaken to unravel the cocktail-party effect before, the AVIL initiative is the most advanced yet. “Now we can go for more realistic, more complex scenes, where we use sound-field synthesis, ambisonics technology and other methods to go to the limits.” He says.

"It’s a great technological playground. Who wouldn’t like to play around with 64 loudspeakers."
Marton Marschall

Watch the video here