We report on ultrasonic investigations of the frequency dependent and temperature dependent sound velocity in pure C-60 and in C-60/C-70-compounds. For both compositions of pressed bulk samples used here elastic anomalies owing to the wellknown transitions at about 260 K and 160 K are observed. Concerning the absolute values of the elastic stiffness our results differ markedly from those found by means of low frequency vibrating reed techniques on C-60 single crystals.