10
Acoustic Models of Sound
Production and Propagation
JAMES L. AROYAN, MARK A. McDoNALD, SPAIN C. WEBB,
JOHN A. HILDEBRAND, DAVID CLARK, JEFFREY T. LAITMAN, and
JOY S. REIDENBERG
1. Introduction
Acoustic models based on physics and mathematics may yield significant
advances in the understanding of sound production, propagation, and interaction associated with whales and dolphins. Models can be used to estimate
the limits of intensity and frequency that are physically possible given the
anatomy of a species. Models can also tell us what kind of anatomical structures would be necessary in order to produce sound having specific characteristics. Models can be used to clarify what type of measurements should
be performed to answer specific questions. Many areas of bioacoustics stand
to benefit from simulation of sound propagation through biological tissues
and the media surrounding them. However, accurate modeling of biological subjects with complex anatomical features is extremely challenging, and
few modern studies exist of sound production and propagation in whales
and dolphins.
In this chapter, we will consider two acoustic models, the first dealing with
the propagation of echolocation signals through the head of a dolphin. This
model combines a novel tissue modeling approach with techniques of
numerical wave propagation to study the acoustic principles operating in
the biosonar emission and reception processes. The second model deals with
the production of low-frequency sounds by the blue whale, Balaenoptera
musculus. The features of blue whale sounds are considered and a sound
production mechanism is derived taking the structures of the whale's
anatomy into account along with the physics of acoustics. The first model
results from the research of Aroyan (1996) and the second model is the
result of research by the remaining authors.
409
Acoustic Models of Sound
Production and Propagation
JAMES L. AROYAN, MARK A. McDoNALD, SPAIN C. WEBB,
JOHN A. HILDEBRAND, DAVID CLARK, JEFFREY T. LAITMAN, and
JOY S. REIDENBERG
1. Introduction
Acoustic models based on physics and mathematics may yield significant
advances in the understanding of sound production, propagation, and interaction associated with whales and dolphins. Models can be used to estimate
the limits of intensity and frequency that are physically possible given the
anatomy of a species. Models can also tell us what kind of anatomical structures would be necessary in order to produce sound having specific characteristics. Models can be used to clarify what type of measurements should
be performed to answer specific questions. Many areas of bioacoustics stand
to benefit from simulation of sound propagation through biological tissues
and the media surrounding them. However, accurate modeling of biological subjects with complex anatomical features is extremely challenging, and
few modern studies exist of sound production and propagation in whales
and dolphins.
In this chapter, we will consider two acoustic models, the first dealing with
the propagation of echolocation signals through the head of a dolphin. This
model combines a novel tissue modeling approach with techniques of
numerical wave propagation to study the acoustic principles operating in
the biosonar emission and reception processes. The second model deals with
the production of low-frequency sounds by the blue whale, Balaenoptera
musculus. The features of blue whale sounds are considered and a sound
production mechanism is derived taking the structures of the whale's
anatomy into account along with the physics of acoustics. The first model
results from the research of Aroyan (1996) and the second model is the
result of research by the remaining authors.
409