|Title||Listener-based Analysis of Surface Importance for Acoustic Metrics
|in||IEEE Transactions on Visualization and Computer Graphics (Proceedings IEEE Visualization 2007)|
Frank Michel, Eduard Deines, Martin Hering-Bertram, Christoph Garth, Hans Hagen |
|Keyword(s)||Sound analytics, Applications of Visualization, Room Acoustics, Phonon Tracing, Acoustic Metric|
Acoustic quality in room acoustics is measured by well deﬁned quantities, like definition, which can be derived from simulated impulse response filters or measured values. These take into account the intensity and phase shift of multiple reflections due to a wave front emanating from a sound source. Definition (D50 ) and clarity (C50) for example correspond to the fraction of the energy received in total to the energy received in the first 50 ms at a certain listener position. Unfortunately, the impulse response measured at a single point does not provide any information about the direction of reflections, and about the reflection surfaces which contribute to this measure. For the visualization of room acoustics, however, this information is very useful since it allows to discover regions with high contribution and provides insight into the influence of all reflecting surfaces to the quality measure. We use the phonon tracing method to calculate the contribution of the reflection surfaces to the impulse response for different listener positions. This data is used to compute importance values for the geometry taking a certain acoustic metric into account. To get a visual insight into the directional aspect, we map the importance to the reflecting surfaces of the geometry. This visualization indicates which parts of the surfaces need to be changed to enhance the chosen acoustic quality measure. We apply our method to the acoustic improvement of a lecture hall by means of enhancing the overall speech comprehensibility (clarity) and evaluate the results using glyphs to visualize the clarity (C50) values at listener positions throughout the room.