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Sound absorption of textile curtains – theoretical models and validations by experiments and simulations.
Pieren R., Schäffer B., Schoenwald S. & Eggenschwiler K., Laboratory for Acoustics / Noise Control,
Empa Materials Science
and Technology, CH-8600 Duebendorf, Switzerland
Textile Research Journal, 88(1), 36-48 (2018).
Abstract:
Textile curtains can be designed to be good sound absorbers. Their
acoustical performance, as usually described by the sound absorption
coefficient, not only depends on the textile itself but also on the
drapery fullness and the backing condition, that is, the spacing
between the fabric and a rigid backing wall, or the absence of a
backing in the case of a freely hanging curtain. This article reviews
existing models to predict the diffuse-field sound absorption
coefficient, which to date can only predict the case of flat curtains.
A set of existing models is extended to the case of curtains with
drapery fullness using a semi-empirical approach. The models consider
different backing conditions, including freely hanging curtains. The
existing and new models are validated by comparing predicted sound
absorption coefficients with data measured in a reverberation room.
Hereby, curtains consisting of different fabrics and with different
degrees of fullness are considered. Besides situations with rigid
backing, also the measurement data of textiles hung freely in space are
included in this study. Comparisons reveal a very good agreement
between measured and predicted sound absorption coefficients. Compared
to currently available commercial sound absorption prediction software
that can only handle the situation of flat textiles with rigid backing,
the results of the presented models not only show a better agreement
with measured data, but also cover a broader range of situations. The
presented models are thus well applicable in the design and development
of new textiles as well as in the room acoustical planning process.
Kurt
Eggenschwiler
EMPA
Abteilung Akustik
Überlandstrasse 129
CH-8600 Dübendorf
Tel. +41 44 823 41 77
Fax. +41 44 823 47 93
E-Mail: kurt.eggenschwiler@empa.ch