Akl and Baz  controlled the Helmholtz resonator
with negative modulus with by coupling with piezoelectric film and applying the electric field.
is an acoustical tool frequently used in applied acoustics.
The Helmholtz resonator
and the seashell demonstrate that a high-quality (i.e., low-loss) spring/mass system can be excited to large amplitude displacements by a vanishingly small exciting force.
Helmholtz Resonator--The Helmholtz resonator
(or cavity resonator), consists of a cavity that is connected to the noisy space through a short neck.
Among their topics are the generalized argument principle and Rouche's theorem, perturbations of cavities and resonators, photonic and phononic band gaps, plasmonic resonances for nanoparticles, near-cloaking, and Helmholtz resonators
, and Minnaert resonances for bubbles.
It was the basis of a series of works of Sugimoto and coauthors [6,7], where the propagation of nonlinear acoustic waves was investigated in a tube connected with an array of Helmholtz resonators
. A mathematical model was proposed, as well as a theoretical analysis and a comparison with experimental data.
corporating new materials with Helmholtz resonators
built into an innovative hollow block and panel tri-layer composite sound wall, designed by himself and Aina Julian, Architect.