The fundamental factor is the relationship between the length of the waveguide and the wavelength : the length of the waveguide must be the integer multiple of the one-half of the wavelength.

It is amplitude of oscillations formed the standing wave field

A standing wave needs some kind of reflective Boundary to develop. The shape is then influenced by the frequency of the wave, the length of the waveguide and the acoustic impedance of the boundary. You can check some classical books about technical acoustic,i.e, Acoustics An Introduction to Its Physical Principles and Applications by ALLAN D. PIERCE.

In my view the wave numbers in acoustic media as well as the boundary condition may be two major factors affecting the standing wave.