A trip through Munich in only a few short minutes: From the traffic noises of Stachus to the center of a concert hall and on to the idyllic chirping of birds in the English Garden. A new laboratory in an anechoic chamber at the Technical University of Munich (TUM) can simulate the widest possible variety of acoustic environments. The chamber, one of the most modern of its kind, was opened today with a scientific colloquium
The anechoic chamber (AEC) is located in a light-gray angular building on the TUM city-center campus. It can even be described as a building within a building: The cube-shaped chamber is suspended freely on a rubber mat in order to minimize the effect of vibrations. The anechoic chamber features walls, ceiling and floor covered with mineral fiber wedges that suppress the reflection of sound.
"The special construction of the AEC lets us conduct acoustic investigations without being disturbed by external factors and reflections from the walls," explains Bernhard Seeber, Professor for Audio Information Processing at TUM, who played a central role in the development of the AEC. The room is suited for a wide variety of experiments. There is even a lift platform that can transport entire vehicles into the chamber in order to investigate their acoustic properties.
60 loudspeakers create audio environments
A 3D loudspeaker system with 60 channels and high-performance computers can simulate entire acoustic environments in an instant. Eight infrared cameras detect the movements of the persons in the room and modify the simulation accordingly. This makes it possible to acoustically place people in locations such as Munich’s English Garden in the shortest of times. Furthermore, it is possible to create spaces in the AEC which exist only on the computer. For example, based on construction plans it would be possible to simulate the sound of an orchestra in Munich’s future new concert hall, even before the excavation work starts.
The spatial acoustics, simulated and made audible in real time using the "real-time Simulated Open Field Environment" (rtSOFE), are not limited to acoustic stimuli. Four 3D video projectors and the corresponding screens can also create virtual visual worlds.
New possibilities for research
What may at first sound like a toy, an approximation of Star Trek’s holodeck technology, is actually the ideal environment for new research projects. "By combining the controlled acoustic environment with projection technologies in the AEC we’ve created new opportunities for investigating the interaction between hearing and vision," says Prof. Seeber. "The knowledge we’ll gain can for example be applied to the development of new hearing aids and cochlear implants."
The AEC was opened today with a scientific colloquium at the Department of Electrical and Computer Engineering. "The field of Technical Acoustics is of interest for many areas in engineering sciences as well as for medicine," says Prof. Wolfgang Utschick, dean of the department. "With its special technical equipment, our new anechoic chamber makes research possible on a whole new level. It will be of great value to our scientists in their interdisciplinary work."