Maximum Sound Absorption by a Monopole in a Room at Low Frequencies

The article considers the problem of sound absorption by a monopole in a room with perfectly hard walls. The radiation impedance of a monopole in the form of a piston built into one of the walls was found. The impedance of the monopole is calculated that ensures the maximum damping constant of the room first natural resonance. It is shown that in the general case, a monopole with an impedance chosen in a certain way absorbs sound more efficiently than a Helmholtz resonator. The proposed approach can be used to design active sound absorption systems for small rooms.