Interaction between Resonators and their Surroundings

The phenomena of acoustical and mechanical resonances are very important in acoustics: (1) The effect of acoustical resonances are used in room acoustics in the construction of resonant absorbing panels; (2) acoustical resonantors are used in the construction of mufflers; (3) the resonance effect determines the quality of musical instruments; and (4) mechanical and acoustical resonances cause an increase in noise produced by machines. In particular cases, different resonator theories are used. In this paper a common theory for resonators, based on the interaction between resonators and their surroundings, is given. It is demonstrated that the conditions of the surrounding medium strongly effect the properties of resonators. By changing the conditions of the medium surrounding the resonators, different changes of resonator parameters can be obtained, namely, changes of sound absorption and sound reinforcement and changes of resonance frequency or selectivity of resonators. The experimental results confirm the above considerations.