Leakage effect in Helmholtz resonators

The effect of leakage in Helmholtz resonators has been investigated in this predominantly experimental study combined with a computational effort. A prototype has been built with varying levels of intentional leakage due to holes in the baffle and gaps between the baffle and the housing. The transmission loss is then measured with different combinations of holes and/or gaps. Such openings, even though their cross-sectional areas are small, are found to have a significant impact on transmission loss. The effect of holes versus gaps is also compared as a function of the leakage area. The present study illustrates the critical need to account for such leakages at the design stage for the proper tuning of these resonators.