A compact acoustic waveguide demultiplexer configuration is studied via finite-element numerical modeling and audio frequency experiments. The demultiplexer consists of a Y-shaped waveguide with a single input and two outputs. The narrow transmission bands created by stubs side-loaded on each output arm lead to selective transmission of certain frequencies. The experimental work characterizes the broadband response along each output arm by using an impulse response method. Finite-element numerical simulations are conducted using COMSOL. The results of the experiment and the simulation are compared to an existing analytic theory.

The application of acoustic ring resonator structures for the manipulation of audio frequency acoustic waves is demonstrated experimentally and via numerical simulation. Three ring resonator systems are demonstrated: a simple single ring structure that acts as a comb/notch filter, a single ring between two parallel waveguides that acts as an add-drop filter, and a sequential array of equally spaced rings that creates acoustic bandgaps. The experiments are conducted in linear waveguides using an impulse response method. The ring resonators were created via 3D printing. Finite element numerical simulations were conducted using COMSOL.