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Fig. 5.7
A virtuoso passage (152 bpm) in a chorus by John McLaughlin on Frevo Rasgado (Gui-
tarTrio
1977
). Note the 'smooth' chord transitions
is a specific improvisation
mode
, in which the musician deliberately chooses to en-
ter and exit, during his solo. Often, virtuoso passages constitute the climaxes of
the chorus. This is obvious in concert recordings such as the GuitarTrio (
1977
)in
which virtuoso passages (see Fig.
5.7
) are followed by enthusiastic rounds of ap-
plauses.
An important apparent characteristic of virtuosity in bebop is that the musicians
give an impression of precisely
controlling
their production, using some sort of
high-level inner commands. Such an impression is obvious when listening to the
effortless character of Art Tatumis' improvisations, which allow him to flow in and
out of harmonies with a total control on their high level structure. Indeed, the impro-
viser's ultimate fantasy is probably not to
produce
but to
control
such a virtuoso flux
(Sudnow
1978
), through high-level mental commands. In short, to be the director of
one's inner orchestra. How is this possible?
5.2.6 Claims
In this chapter, we make a number of claims. The main one is that we present a sys-
tem that generates virtuoso phrases of the same musical quality as the ones human
virtuosos produce. The validity of this claim is left to the appreciation of a trained
jazz listener, who can judge from the outputs (scores and videos) of our system,
Virtuoso
, available on the accompanying web site.
The second claim is that we propose an operational answer to the virtuosity ques-
tion (how do they do that?), by introducing the notion of
intentional score
:thetem-
poral series of high-level musical decisions taken by the virtuoso to generate a cho-
rus. These decisions are arbitrary, and may be seen as the '
1%magic
' mentioned
by Levine in his introduction (see Sect.
5.2
). This intentional score is the backbone
for automatically producing virtuoso phrases, and our system may be seen as an
in-
terpreter
of this score, which generates a chorus that satisfies it, i.e. Levine's '
99 %
stuff
'. We show through our various examples that this score suffices to generate
virtuoso phrases of high quality. All the decisions in the intentional score are done
at the
beat level
(and not at the note level), i.e. at a
low frequency
, thereby substan-
tially reducing the cognitive load of rapid note-level decision making. This explains
how the bypass of high-level cognitive decision-making may be operated in practice
(see Sect.
5.1.2
).
Most importantly, we show how human jazz improvisers have contributed, at
least in two respects to
inventing the bebop style
(and its extensions)
thanks to
