Existing research has shown that single-voice entries in polyphonic music are more easily perceived than single- voice exits. A study of 195 assorted musical works reveals a marked asymmetry between voice entries and exits. Specifically, voices tend to be added one at a time, while voice exits tend to occur several at a time. This practice is consistent with the hypothesis that voice entries and exits are perceptually important points in musical works and that composers avoid single- voice exits because they are less likely to be perceived.

References

References
Huron, D. Voice denumerability in polyphonic music of homogeneous timbres. Music Per- ception, 1989, 6(4), 361-382.
Huron, D. & Fantini, D. The avoidance of inner- voice entries: perceptual evidence and mu- sical practice. Music Perception, 1989, 7(1), 43-48.
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