For all RealTracks there is an algorithm which cuts and pastes and sometimes pitch-transposes snippets out of a real - very long - audio-recording - by motif or phrase - in order to conform to the desired chord at each change in chord-progression.

Although the algorithm will try and use patterns that were played in the same key/scale type as the desired chord - where this isn't possible the algorithm uses pitch-transportation (zPLane) to transpose the original audio motif ( bass-line phrase ) to the new root.

The problem comes when there is a transition between one chord and the other - where the last note played in the bar of the prior chord gets followed by the first note in the new bar and chord - but where there is clearly no "Musicality" in how the last note in the old chord leads into the first note of the new.

This problem is particularly noticeable for Jazz style bass-lines that "walk".

Often the transition is smooth and musical sounding - which in most cases means that the notes and patterns aren't that far from each other in pitch. In this case the cutting and pasting of phrases (bass-line sections) has worked fine. And the result sounds authentic.
Something Ron Carter MIGHT DO.

But sometimes there is a considerable jump - and the "bass player" just does something that a real one wouldn't . In such cases the new phrase is pasted in - at say more than a 5th above the last note and it becomes obvious that this is TWO different motifs taken from somewhere in the long original recording made by the session musician hired by PG in the studio. And just crudely glued together in a manner in which the walking bass-line really doesnt "walk" like any real bassist.

and this includes RealTracks by Ron Carter himself.

One reason for these abrupt transitions is - i think because BIAB only does zPlane pitch transformations on phrases as a WHOLE. If the algorithm were to be improved so that individual notes of a [MONOPHONIC] phrase were able to be changed and transposed - then the melodic type leading notes and more natural melodic contours of walking bass lines would sound more realistic.

As it is - it isn't too hard ( for a jazzer or pro musician ) - I contend - to spot a BIAB generated double-bass walking line compared to an original walking bass-line as done by any competent jazz ( or other ) bassist.

Last edited by nonchai; 12/29/18 04:31 AM.
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