The calculation of the acoustic room mode is based on the following formula:
$$ f_{n_x,n_y,n_z} = c_0 \left[ \frac{1}{2} \left( \left( \frac{n_x}{L_x} \right)^2 + \left( \frac{n_y}{L_y} \right)^2 + \left( \frac{n_z}{L_z} \right)^2 \right)^{\frac{1}{2}} \right]. $$