The study explores the problem of forming an acoustic field in the Helmholtz resonator cavity using the mode-matching method. Acoustic boundary value problems for the description of acoustic fields in resonator cavities under traditional boundary conditions and boundary conditions at the edge (and in its absence), which is characterized by the known acoustic properties, are set and solved. For certain dimensions of an air-filled resonator, the basic field characteristics in the resonator are calculated, analyzed and compared with experimental data. The influence on the results of field formation of the involved condition at the edge with acoustically rigid boundaries-surfaces is estimated. In view of the foregoing, the research aims to formulate and solve the wave problem of acoustic field formation in the cubic Helmholtz resonator taking into account classical boundary conditions, conjugation conditions, and conditions at angular points of structural elements formed by the mode-matching and applying the eponymous method.