Engineering Noise Control
| Date: 28 April 2011, 03:53
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Although this third edition follows the same basic style and format as the first and second
editions, the content has been considerably updated and expanded, partly in response to
significant advances in the practice of acoustics and in the associated technology during
the seven years since the second edition and partly in response to improvements,
suggestions and queries raised by various practitioners and students. The emphasis is still
on passive means of noise control but as in the second edition, the book contains a
chapter giving specific consideration to active noise control. This particular chapter has
also been considerably updated and modified since the second edition.
Chapter 1 includes new material discussing practical approaches to noise control and
an expanded discussion of noise control strategies. The section on the speed of sound has
been expanded to include the effect of the compliance of containing boundaries on the
longitudinal wave speed in contained fluids and the discussion of wavelength and
frequency is now better illustrated. A section illustrating how two or more waves of the
same frequency travelling in the same or opposite directions may be combined, thus
leading to the introduction of the concepts of plane and spherical standing waves. A new
section on energy density has been added, the discussion on octave and 1/3 octave band
analysis has been expanded to include the derivation of the band widths and centre
frequencies and the section beating has been expanded to include a mathematical
derivation of the phenomenon for combining waves of slightly different frequency and of
similar or very different amplitudes to produce heavily or lightly modulated beating.
The description of the ear in Chapter 2 has benefited from recent advances in the
understanding of that amazing mechanism. In particular, the roles of the inner and outer
hair cells as well as the efferent and afferent nerve systems have been clarified, as has the
phenomenon of wave propagation and wave stalling on the basilar membrane. Both the
“un-damping” phenomenon and the “half-octave shift” phenomenon are explained with
reference to physical and mathematical models. In addition, the discussion of masking
has been extended and equal loudness contours for octave bands of noise have been
added.
In Chapter 3, the discussion on sound level meters (including taking measurements in
windy conditions) and noise dosimeters has been updated. A section on the measurement
of energy density has been included and the newly developed transducers that directly
measure particle velocity have been introduced.
Chapter 4 has included in it considerable new material defining the various measures
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