DAGA 2010 - Deutsche Gesellschaft für Akustik eV

Programm DAGA 2010 219
of instruments. Dozens of orchestral instruments were measured in this
way, allowing to build a database for their directivities. These data can
be used for computer simulations, as well as for sound reproduction by
using a technical sound source that resynthesizes the radiation patterns
of the measured instruments.
Mi. 14:50 Bauwesen H2 Virtuelle Akustik I
Comparison of acoustic centering maps for radiation capture of
musical instruments with spherical microphone arrays
D. Deboy und F. Zotter
Institut für Elektronische Musik und Akustik, KU Graz
Recently, the capture of sound radiated from musical instruments has
been topic of research, using surrounding spherical microphone arrays.
Astonishingly, spatial aliasing errors of these arrays depend on accurate
acoustic centering of the sound source as shifting yields higher-order
spherical harmonic components. Acoustic centering, however, is nontrivial
for musical instruments if not impossible. Therefore using different
measures like weights of spherical harmonic components can be used to
roughly track the acoustical centre for each partial of the musical sound
after the recording has been made. Eventually, the paper investigates
different strategies for tracking with respect to the uniqueness of the positions
by visualizing their time-varying localization map. The suggested
method shall give a more compact description of radiation-patterns extracted
from spherical microphone array recordings, which can be more
efficient in further analysis and synthesis processes.
Mi. 15:15 Bauwesen H2 Virtuelle Akustik I
Study of phase reconstruction methods employed at room acoustic
simulation
B. Masiero und S. Pelzer
Institut für Technische Akustik, RWTH Aachen
For an increase in truthfulness of room acoustic simulations, the directivity
of the sound sources must be taken into account. But the information
of source directivity is usually stored in the directivity balloon format, only
containing sound pressure level information, thus neglecting all phase
information. Now, a spectrum with inadequate phase component might
lead to disastrous results when simulating impulse responses. Phase reconstruction
methods with varying degree of complexity can be applied
to guaranty a causal and/or continuously decreasing impulse response.
This work deals with the question if humans can differentiate the impulse
responses with different phase components. This question will be
answered based on comparative listening tests, which presents various
types of signal (e.g. excerpts of speech or music) convolved with simulated
impulse responses of three rooms with varying reverberation times.
For each room, three different impulse responses are simulated, each
based on a different phase reconstruction method.