The common design of passive low-reflecting acoustic terminations mostly include Helmholtz resonators, quarter-wave resonators, Meta Material, duct area expansion (this refers to all kinds of horns with a gradual or step-wise increase of the wavefront area), use of acoustic absorbing materials (fibrous, porous, reticulated, micro-perforated, etc.), and so-called “acoustic black hole” based constructions (typically consisting of a range of discs with holes of decreasing diameters separated by cavities). The practical implementation of the low-reflecting terminations usually combines several of the above-mentioned design principles.

Despite numerous proposed constructions, the problem to provide a compact, passive, robust, and well-performing acoustic termination which works in a wide frequency range for all kind of the applications is still actual. This is especially problematic if the ultra-low frequency range is considered. The crux of the problem is related to the difficulty of efficiently absorbing or radiating waves of long wavelengths.

The high-tech technology of the newly developed mufflers at ATA Mute has a huge potential to satisfy the challenging demands of noise mutation. Due to the small size of the mufflers, they can be integrated relatively easily inside or outside appliances without significantly affecting the final size, weight, or cost of the appliances.