In this research area we focus on the electro-acoustical generation of sound and the interaction with room acoustics. A specific challenge is to adapt loudspeaker playback to accommodate for the acoustical properties of the playback room such that playback is as faithful as possible to the original recorded sound scene.
For the sound reproduction a transducer is used to convert electrical energy into a mechanical movement. The most common motor principles are the electromagnetic, electrostatic and piezoelectric devices. An electromagnetic loudspeaker, for example generates movement with a suspended diaphragm that is driven by a voice coil (electric wire) inside a magnetic field. Due to the polarity of the current, the coil creates a vibration of the diaphragm which leads to an alternating pressure change of the air around the diaphragm. These changes in pressure spread out as a wave and can be perceived by a listener.
The sound propagation does not develop independently of the room in which the loudspeaker is place, but instead spreads to all sides and interacts with the room’s floor, walls, ceiling and objects on their way. Below are two examples of a musical instrument played in two different rooms with the microphone at the same distance.
The quality of sound that is perceived is therefore not only dependent on the production but is also influenced by the interaction with the reproduction room.
In most practical situations it is impossible to reproduce the physical sound field with such accuracy that there are no perceivable changes in comparison to the recorded sound field. In this research area, the goal is to come to a better understanding of the perceptual requirements that need to be met in order to reach a faithful audio reproduction and to learn how this can be achieved with electro-acoustical systems. For faithful audio reproduction we consider both plausible reproduction, where one believes the audio source could be real without knowing the reference, and authentic reproduction where the reproduced audio source cannot be distinguished from the original sound source.