As already mentioned, an axial mode consists in an acoustic wave between two surfaces whose wavelength is a multiple of the distance between the two surfaces, and the frequency of the wave in question is called resonance frequency.
We have established that the distance between the walls influences the frequencies of the modes that are stimulated. The arising of modes is a phenomenon that must be kept under strict control, in that they risk heavily tampering the frequency content of a sound within a closed environment.
