Sebastian Merchel Research SweetSpotter

The spatial reproduction of sound in a conventional stereo system works in a small area which is located on the symmetry axis between the loudspeakers – the so called sweet spot. Beyond this area, the spatial perception collapses and the stereo image moves to the nearer loudspeaker since the signal arrives both louder and sooner. Finally, the stereo image is completely located in the nearer loudspeaker due to the precedence effect.

Although stereophony has a long history, the listener has not yet been released from its static hearing position.

SweetSpotter demonstrates a playback system which adjusts both loudspeaker signals depending on the listener’s position in real-time. The position and orientation of the listener is tracked by a webcam and a face recognition system (head tracking). This information is used to calculate the amount of delay and amplification in the corresponding audio channels.

Thereby, a correct phantom source localization over the whole off-center listening area is achieved.

Sebastian Merchel and Stephan Groth: Analysis and Implementation of a Stereophonic Play Back System for Adjusting the “Sweet Spot” to the Listener’s Position, Journal of the Audio Engineering Society, 58(10) 2010, 809–817.