In music, voice leading is the continuity between pitches or notes played successively in time. For example, when moving from a root position C triad or chord played C-E-G to an F triad in second inversion, played C-F-A, you might say that the middle "voice" rises from E to F while the top "voice" rises from G to A, this being a way to "lead" those voices. Instead of thinking of the two successive chords vertically as separate, we are concentrating on the "horizontal" (temporal or linear) continuity between notes. Concern for voice-leading often means a predominance of stepwise motion and may assist or replace diatonic functionality.

An auditory stream is a perceived melodic line and streaming laws attempt to indicate the psychoacoustic basis of contrapuntal music. It is assumed that "several musical dimensions, such as timbre, attack and decay transients, and tempo are often not specified exactly by the composer and are controlled by the performer." An example of one law is that the faster a melodic sequence plays the smaller the pitch interval needed to split the sequence into two streams. Two alternating tones may produce various streaming effects including coherence (perceived as one unit), a roll (one dominates the other), or masking (one tone is no longer perceived).

See also: tonality, chord progression, polyphony.

Further reading

• McAdams, S. and Bregman, A. (1979). "Hearing musical streams", in Computer Music Journal 3(4): 26-44 and in Roads, C. and Strawn, J., eds. (1985). Foundations of Computer Music, p.658-698. Cambridge, Massachussetts: MIT Press.