David Oliva Elorza - Room Acoustics Modeling Using The Raytracing Method.pdf

(10215 KB) Pobierz
untitled
Room acoustics modeling using the ray-
tracing method: implementation and
evaluation
Licentiate Thesis
University of Turku
Department of Physics
2005
David Oliva Elorza
2
3
A mi abuelo
4
Abstract
This thesis discusses room acoustics modeling and the basics and drawbacks of different
methods. Then it concentrates on the ray-tracing algorithm, and offers the author's
implementation of the method and an evaluation of its accuracy when comparing
modeled sound decays and predicted acoustical parameters with the corresponding
measured data in three different enclosures.
First, a general introduction of the sound propagation principles and a discussion of the
state of the art in room acoustics modeling are given. How to implement the ray-tracing
algorithm is explained, not only the way adopted by the author but also other
possibilities which could improve accuracy. That is followed by a geometrical and an
acoustical description of the three studied enclosures, and the comparison of the
modeled and measured data. Sound pressure level is predicted with very good accuracy,
while reverberation time is more contradictory due to the negation of the wave nature of
sound which is inherent in the model. The paper ends with a discussion of the results’
accuracy and the reasons for similarities and/or differences.
5
Preface
In August 2004 I started to write this thesis. In principle, it had to include the form of
the ray-tracing method that I had implemented during my time in the Finnish Institute of
Occupational Health (Työterveyslaitos), together with the evaluation of its accuracy in
some indoor enclosures, but it turned out to include more than that. The referred method
is good, although it is not perfect and it has several drawbacks. Hence, I finally ended
up writing down many things which in principle were outside the scope of the thesis,
but that constituted a part of the whole. That is, I discussed diffraction at great length
although I had not yet implemented it, but just because I thought I might do so some
day. Therefore, it became a very long paper, which could be hard to read for some
readers, useless until page 56 or 70 for others, and for the rest of them utterly pointless.
I do not know yet into which category my thesis reviewers belong, but maybe to one of
them. Their opinion made me work a little harder on the paper, delete about twenty
pages, and reorganize most of it. However, that was very positive, not only because this
thesis now looks better than it did before, but also because I have improved my
knowledge. A lot of time has passed since I typed the first lines of this paper, but on the
other hand, I have been doing some other things since then. For instance, the form of the
algorithm which is currently on my hard disk differs considerably from the one
described in this work, and my expected future work, and even more has already been
done. However, that is definitely another story about which I will perhaps still write
some day. Just one more thing: if you decide to go on with the reading of this thesis,
please, enjoy it!

Plik z chomika:

Inne pliki z tego folderu:

Inne foldery tego chomika:

Zgłoś jeśli naruszono regulamin