A second consideration is that a useful synth vco is expected to output several different waveforms , so that the synth player has harmonic starting points for creating a given sound .
In a four-cylinder engine , the forces caused by the primary harmonic of the crankshaft 's rotational frequency can be balanced by arranging one pair of pistons to move down while the other pair moves up .
Every harmonic and melodic idea of the composer is there ; one can trace just as clearly the subtle processes of his mind ; every step in the working out of the materials is just as plain .