Weishampel (1981) did an extensive study of the vocalization potentials of the crest paying
particular attention to the Parasaurolophus. He equated its tube with a trombone and by
application of simple acoustical theory, he calculated the resonant frequencies of a tube.
Long tubes resonate with lower frequencies than shorter ones. The lowest note obtained from a
given tube is called the FUNDAMENTAL FREQUENCY. Weishampel calculated the fundamental
frequency for the Parasaurolophus to be 48Hz.