The scattering coefficient is one of the most important input parameters in room acoustics simulations. Together with absorption coefficient they belong to main descriptors of interior surface properties in the calculation process based on ray or radiosity method algorithms. This paper investigates the influence of scattered sound on the objective room acoustic parameters in the example of a virtual concert hall. Six different alternatives were simulated, where scattering coefficients s = 10, 30, 50, 60, 70 and 90 % respectively, were applied to the interior surfaces of the ceiling, side and rear walls. Analysis has been performed by studying the results of objective room acoustical parameters predicted by simulations done in the software Catt- Acousti