A Dictionary of Music and Musicians/Preparation
PREPARATION. The possibility of using a very large proportion of the dissonant combinations in music was only discovered at first through the process of 'suspension,' which amounts to the delaying of the progression of a part or voice out of a concordant combination while the other parts move on to a fresh combination; so that until the delayed part moves also to its destination a dissonance is heard. As long as the parts which have moved first wait for the suspended notes to move into their places before moving further, the group belongs to the order of ordinary suspensions (Ex. 1); but when they move again while the part which was as it were left behind moves into its place, a different class of discords is created (Ex. 2).
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