This paper shows the possibility of calculating the absorption characteristics of the most intense X**1 SIGMA -A**1 PI and X**1 SIGMA -E**1 SIGMA bands of SiO vapor in the 2000-10,000 degree K temperature range, by means of a random Elzasser band model approximated to a composite line contour. The random Elzasser band model consists of a statistical superposition of the different Elzasser subbands, each with its own parameters.