Helmholtz resonance is widely used in various engineering applications and especially in noise reduction systems. While the phenomena itself is well-known, it still plays an important role in the development of modern concepts, such as acoustic metamaterials or bound states in the continuum. In this work we explore high-Q states occurring in an open system of two coupled Helmholtz resonators. When the coupling is strong, the in-phase and out-of-phase excitations of the resonators are possible, which are characterized by the symmetric and anti-symmetric spatial field distributions. We demonstrate that the quality factor of the anti-symmetric resonance may reach values beyond 1000. Using numerical calculations, we analyze the behaviour of the system under the symmetry break and describe the formation mechanism of these high-Q states. The obtained results provide a route towards development of novel resonant systems, such as filters, absorbers and sensor.