Extensive band structures have been computed for periodic arrays (in the ho
neycomb structure) of rigid metallic rods in air. Multiple complete acousti
c stop bands have been obtained within which sound and vibrations are forbi
dden. These gaps start opening up for a filling fraction f greater than or
equal to 8% and tend to increase with the filling fraction, exhibiting a ma
ximum at the close-packing. th tandem structure has also been proposed that
allows an ultrawideband filter for environmental or industrial noise to be
achieved in the desired frequency range. This work is motivated by the rec
ent experimental observation of sound attenuation on the sculpture by Euseb
io Sempere, exhibited at the Juan March Foundation in Madrid [21] and compl
ements the corresponding theoretical work [22, 23]. (C) 1998 Academic Press
.