Strutt|Fundamentals|Wavenumber inserts the wavenumber of a sound wave in air into each octave band or 1/3-octave band of the selected row.
The wavenumber (`k`) is calculated as:
`lambda = c//f` is the wavelength of the sound wave
`c` is the wave velocity, temperature dependent (343 m/s at 20 °C)
`f` is the frequency of wave (Hz)
The user may calculate the wave velocity as a function of temperature (using the Speed of Sound calculation) or else use the default value of 343 m/s.