Аннотация:The Q factor of a resonator is a constant, which gives an estimation of its ‘‘quality.’’ A system with a high Q can accumulate high energy and provide markedly nonlinear phenomena even in the case of weak power sources. At small amplitudes Q is limited by linear absorption caused by both the medium inside the resonator and its boundaries. As the amplitude increases, nonlinear absorption and frequency response distortion come into play, and Q is determined by both system design and the acoustic field strength. In general, nonlinearity leads a to significant decrease in Q. One can enhance Q in different ways using impedance boundaries whose frequency‐dependent response destroys shock fronts, a medium containing selective absorbers suppressing shock formation, resonators of special shape, or special types of excitation to counter the distortion. Data on nonlinear Q‐factors and response taking into account dissipative and frequency‐dependent properties of systems are presented.