A
Virtual Piano Concerto
Coupling
of the Mathews/Boie Radio Drum and the Yamaha Disklavier Grand Piano in
"The Seven Wonders of the Ancient World"
David A. Jaffe
W.
Andrew Schloss
295 Purdue Ave. School
of Music
Kensington, CA
University
of Victoria
94708 U.S.A. Victoria,
B.C. V8W 2Y2
david@jaffe.com CANADA
aschloss@nero.uvic.ca
1 Introduction
We
describe here the process of collaboration that went into the creation of a The
Seven Wonders of the Ancient World a seventy-minute, seven-movement concerto by
Jaffe, scored for remote-control piano and an acoustic ensemble of eight
instruments. The solo piano part,
written specially for Schloss and developed in collaboration, for the Yamaha
Disklavier C7 Grand Piano Mark II (a piano that can "play itself"
under computer control) and the Mathews/Boie Radio Drum [Boie et al, 1989] (a
device that conveys three-dimensional gestures to a computer.) The
Drum and Disklavier are connected via a Macintosh computer running software
created with MAX (Puckette/Zicarelli.)
Thus, the final result of this work is entirely acoustic.
The
piece was developed in four stages: initial research on the "percussionistic"
use of the Drum (Schloss), exploration of the Disklavier and of the
Drum-Disklavier interaction (Jaffe, with extensive input from Schloss),
composition of the work itself (Jaffe), and a period of refinement of the solo part (Schloss, with extensive input
from Jaffe.) This mode of
collaboration was markedly different from the authors' previous collaboration,
Wildlife[Jaffe and Schloss, 1992 and 1994], a collaboratively-composed and
-performed work [Jaffe and
Schloss, 1994]. In this paper, we
distinguish between the contributions of the authors by referring to them as
"the composer" (Jaffe) and "the performer" (Schloss). The reader is requested to keep in mind
that this division simplifies to some extent the actual collaboration that took
place, as well as the fact that in a quasi-improvisational context the boundary
between composition and performance is somewhat blurred.
The
first four movements of The Seven Wonders have been completed and were recorded
at the Banff Centre for the Arts in 1993 and premiered at the University of
California at San Diego in May 1994.
These three movements, taken as a group, are known as "Part I"
of the work. The remaining three
movements are in progress.
2 The Seven Wonders of the Ancient
World
Two
statues, a temple, a roof-top garden, two tombs and a lighthouse. This rather odd collection of monuments
has come down through history as "The Seven Wonders of the Ancient
World." All but one (the
Pyramids) have been destroyed, either by Nature or by human hands. A closer look at the Wonders reveals a
crosshatch of parallels and oppositions.
Two deal with death the Pyramids and the Mausoleum. The Hanging Gardens glorify cultivated
nature, while Artemis was the goddess of wilderness and wild animals. The two statues are of the heavens Zeus,
the god of thunder and rain; and the sun god of the Colossus of Rhodes. How can the essence
of these monuments be conveyed in music?
In searching for an answer, the composer turned to the Disklavier and
the Radio Drum, the latter used in a percussive manner. Note that this differs from the
conductor paradigm followed by Max Mathew's "Conductor" software
[Mathews, 1988], and used in the composer's Terra Non Firma [Jaffe, 1994].
The
sound of the Drum-Piano is further expanded by an unusual ensemble consisting of
instruments that extend the piano's sound five plucked string instruments
(harp, mandolin, guitar, harpsichord, and contrabass), two percussionists who
play primarily pitched instruments, and one instrument capable of sustained
sound (harmonium). In addition,
the contrabass sometimes plays arco, providing another sustained sound. Since these instruments are used in a
predominantly orchestral role, we refer to them as the "orchestra," despite
the relatively small size of the ensemble. Finally, an improvisational approach to extended cadenzas in
the solo part allows the performer to respond and communicate intimately with
his unusual instrument. The result
is a new kind of piano concerto.
3 Methodology
3.1 Building an Instrument, Part 1:
The Controller
The
Radio Drum part is based on the foundation developed by Schloss during the period
1988-1990 [Mathews and Schloss, 1989].
After much experimentation, the percussionist's apparatus stabilized as
follows: He performs on the Radio
Drum with two mallets, allowing six degrees of freedom, while his feet control
an Elka MIDI organ foot-pedal, a polyphonic device consisting of 18
velocity-sensitive pedals.
Both devices send information to a Macintosh computer. Each of the Drum mallets may be in one
of two modes. In "whack mode",
the Drum sends data each time its surface is struck (more precisely, each time
the mallet changes direction.) In
"continuous mode", the Drum sends position data, whenever it is
polled by the computer, usually continuously.
3.2 Building an Instrument, Part 2:
Radio Drum Meets Piano
Work
on this piece began with a series of experiments (or "sketches") in combining
the Drum and Disklavier, during the summer of 1992 at the Banff Centre for the
Arts, where the authors were Resident Artists. The composer discovered that the flexible and seemingly-magical
mapping of percussion gestures onto piano mechanism makes possible the grand,
monumental, yet very uncharacteristically "pianistic", sounds the
Seven Wonders idea called for. We
created a set of quasi-improvisational scenarios, each with a strong immutable
identity, but allowing the performer an opportunity to interact with a strong
sense of immediacy with the Drum-Piano [Schloss and Jaffe, 1993].
A
variety of approaches were used in exploring the rich space of possibilities. First, the composer explored
compositional ideas on the Disklavier alone, focusing on effects that would be
difficult or impossible if the piano were played in the conventional manner. Later, the parameters were refined and
mapped onto the Drum. Since the effect
of a given gesture on the Drum is entirely up to the composer, the Drum often
controls aspects of compositional algorithms.
Other
effects were conceived with the Drum itself in mind. One of the most intriguing aspects of the Drum-to-Piano
transformation is that it enables the idioms, conventions and vocabulary
studied by percussionists to be applied to the alien world of piano sound
production. In one case, we
created a "drum set" in which regions of the Drum surface correspond
to musical gestures on the piano.
For example, one region might play a rapid trill, another might play a
staccato chord, a third might play a quick series of notes. The gestures are all short enough to
allow the performer to play the Drum as if it were a trap set, but one in which
each "instrument" is actually a piano motive. Often, the composer would implement a
configuration, the performer would try it, and then the performer would suggest
a modification (see section 4.1).
Occasionally, this interaction was reversed, as in the "rhythmic
grid" of movement III (see section 3.3)which was suggested by the
performer, then implemented and refined by the composer, who played the Drum
part himself as a way of exploring its potential. This illustrates the fluidity of roles typical of the
collaborative process, with the performer assuming aspects of the composer's
role and vice versa.
3.3 Compositional Strategy
The
third phase involved the composition of the orchestral parts and was carried out
by the composer alone during the period January 1993-May 1993. He returned to California armed with a
set of some twenty completely different approaches to interaction between the
Drum and Piano, as well as several hours of recordings of improvisations with various
Drum-Piano configurations.
He then began structuring this material into a concerto, proceeding by
selecting one or two highly-characteristic approaches for each movement of the
piece and structuring the movement around them. Examples are given below from the first four
movements.
The
first movement, The Pyramids, is based almost entirely on 88-note effects in
which every note of the piano is played on each gesture (see section 4.1). The orchestral material is
complementary, much of it based on chromatic tone clusters. For example, an extended passage for
harpsichord, mandolin, guitar and harp rhythmically explores an 18-note tone
cluster melody, with each instrument playing some portion of that cluster and changing
which portion it plays as the melody moves. The harmonium and arco bass also figure prominently in this
movement, playing tone clusters and minor seconds that swell and fade, growing
and contracting. The second half
of the movement is an extended Drum-Piano solo with commentary by the timpani
and glockenspiel, leading eventually to a climax whose resonance is allowed to
ring throughout a coda section, in which this resonance is taken up by the
harmonium, guitar, low harp and bass playing harmonics.
The
second movement, The Hanging Gardens of Babylon, is built on a simple melody,
ornamented in a variety of ways.
Here, the Radio Drum controls a "time map" that influence show
far cascading melodic strands drift with respect to one another, floating between
homophonic and canonic textures.
The orchestral material is similarly conceived, with melodies that
proceed with like melodic contour, but not in lock-step synchronization.
The
third movement, The Statue of Zeus in the Great Temple of the Sacred Grove, is
based on pulsations at various conflicting tempi. The Drum performer improvises in the context of polyrhythms
by moving within a "metrical grid," performing cross-rhythms and
creating metric modulations as
each new rhythm is "latched" to become the dominant pulse. The orchestral music is similarly based
on conflicting pulsations. At one
point, the orchestra's multi-rhythmic patterns suddenly become homogeneous as
the Radio Drum breaks into an improvised solo that attempts to contradict the
pulsations of the orchestra.
The
fourth movement, The Colossus of Rhodes, is entirely based on trill-derived
material, performed by the Radio Drummer (see section 4.2) and taken up by the orchestra
using a technique of gradual disintegration of ensemble, in which the conductor
begins conducting and then stops, allowing the instruments to drift out of
synchronization until they all arrive at the final trilled fermata [Brant,
1980]. Eventually, the trills morph
into a wild fiddle tune, performed by the Radio Drummer over a string band accompaniment,
eventually disintegrating into a
rhythmic chaos that finally leads back to the trills.
3.4 Shaping the Performance
The
final phase involved refining the improvisational cadenzas and structuring the
software into a series of sequential cues. This work was carried out at CNMAT (U.C. Berkeley) and the
Banff Centre for the Arts in July 1993.
Before the solo part could be shaped, we had to devise a system of sequential
cues so that the various configurations of the Radio Drum could be accessed as
specified in the score. This was
done by introducing a global "current cue" variable that selects the
appropriate functionality. One
pedal is used to advance to the next queue, while another is reserved for
stepping back a queue for rehearsal purposes. There is also a graphical user-interface that allowed for
random access to any queue.
Shaping the solo part required extensive
practicing with each of the Drum-Piano's improvisational scenarios. The performer began by executing the
instructions in the score as written, asking questions of the composer when
necessary. In most cases, coaching
by the composer, plus long sessions in which the performer alone explored the
possibilities of the scenarios, were sufficient to refine the solos. Sometimes the performer would add detailed
annotations to the composer's general instructions, to remind himself to focus
on aspects of the improvisational space that he found particularly
effective. In one or two places, these
additions took on a structural significance and were added to the score
itself. The final result still
left the performer a good deal of room to improvise in the performance itself,
but with "guide-posts" enabling him to find his way and allowing the
conductor to fit in the orchestral part.
4 Challenges and Opportunities
A
number of challenges were involved in the creation of this piece. Each posed a problem, but also
presented opportunities for innovation.
The first was to discover ways of using the Drum-Piano combination
idiomatically so that the strengths of each instrument are maximized, while the
weaknesses are minimized. The
second challenge was to work within the physical limitations of the Disklavier,
which are entirely different from those of a synthesizer or sampler. In approaching this issue, we were led
to some fascinating algorithms that we would have been very unlikely to find
had we not been required to work within the constraints of the piano
mechanism. A third challenge was
to provide the performer with enough freedom to take advantage of the
expressive potential of the RadioDrum, while remaining in the context of a
fully-composed concerto.
4.1 What is "Idiomatic" for
the Drum-Piano?
The
Radio Drum is excellent for playing rapidly and for controlling multiple
independent variables at the same time.
However, it is not very good at random access to a large set of discrete
values, such as the pitches of a piano. Therefore, when exact pitches were required, we used a
"sequential drum" mode, in which each note of a stored sequence is
splayed each time the Drum is struck.
A different version of the sequential approach is used in "The
Hanging Garden of Babylon."
Here, a pre-composed melody is played, duplicated at several
transposition levels, while the Drum controls the drifting of the voices with
respect to one another, using a real-time performance "time map"
[Jaffe, 1985]. The Drum's left mallet is in continuous mode here
and implements the following mapping:
The x axis determines how far the voices move out of
synchronization. As the performer
moves the mallet to the right, the voices move from unison rhythm to a kind of
heterophony, and eventually to a canonic texture. The y axis controls dynamics. The right mallet restarts the melody.
Similarly,
the piano is constrained by a number of factors, not the least of which is the
geometry of the human hand. In an
effort to exploit the Drum-Piano combination in an idiomatic manner, we explored techniques that would be
awkward or impossible if the piano were played in a conventional manner. For example, for "The
Pyramids", the composer was interested in creating ponderous massive
blocks of sound, each comprising all 88 notes of the piano. We devised a mapping of the Drum in
which all 88 notes of the piano are played each time the Drum surface is struck
with the left mallet, with the speed and loudness of these notes corresponding
to the y value and how hard the
Drum is struck, respectively, and the
x axis controlling the "correlation" of these notes as
follows: The right side of the
Drum corresponds to the most correlated effect a single 88-note chromatic glissando. The left side of the Drum corresponds
to the least correlated effect 88 notes in random order. Between these points are such
combinations as 4 groups of 22-note glissandi, 8 groups of 11-note glissandi,
etc. Multiple instances of this
process can be active at once.
The
score calls for the performer to improvise with this mapping for several minutes. After extensive experimentation, we
decided the performer needed more control over the configuration. This led to a modification of the
original plan: As originally implemented,
the direction of each glissando was randomly determined. However, the performer wanted to be
able to create multiple cascading glissandi in the same direction. Therefore, wemodified the algorithm to
allow assignment of glissando direction from a foot pedal. Also, the performer found that slow
88-note gestures could continue for an annoyingly long time, leading to an
undesirable plodding effect; he wanted a way to stop the gesture midstream. So we gave the right mallet a special
role; it stops the most recently-begun instance. For example, the performer can start a slow 88-note
glissando, play several other gestures on top of it and then stop several of
the latter gestures while the initial gesture continues. This mapping allows for a great deal of improvisational
variety, despite the severe constraint that each Drum stroke produces 88 notes.
4.2 Physical Limitations of the Piano
as a Source of Inspiration
The
physical limitations of the Disklavier include the duration required for a
piano key to bounce back before it can
re-strike the strings; the number of notes that can be played simultaneously;
the maximum duration a note or the pedals can be held down; and thedelay
between the reception by the piano of a MIDI message and the sounding of the
corresponding note, which depends on the velocity with which the string is
struck. The process of working
around these limitations led to discovery of an interesting set of effective
mappings from the Drum to the Disklavier that we would have never found were not
working within the confines of the piano's limitations.
For
example, the score called for an improvisational scenario in which the Drum's X
axis is mapped to pitch and the performer's left hand played four-octave chords
in a D major scale, while the right hand played the same chords in a D minor
scale. As soon as the
performer started playing quickly, the limitation in the piano's action became
problematic. The solution we
discovered was to constrain the piano to never repeat the same pitch
twice. If the performer attempts
to strike the same location on the Drum surface twice, the pitch "dithers"
in the vicinity of the pitch corresponding to the location where he struck. This
dithering is in the context of the scale of the hand with which the performer
played. For example, if the left hand plays a G and the right hand then strikes
the same location on the Drum, the resulting pitch is F-natural. However, if the right hand plays
a G and the left hand then strikes the same location on the Drum, the resulting
pitch is F-sharp. This simple
variation on the original design was an enormous improvement. The performer could now play as fast as
he wanted and the piano kept up beautifully. More significantly, the resulting musical effect was
substantially more effective and intriguing than that of the original
design. This is especially
apparent when the Drum is switched to the continuous mode. In this mode, even when the mallet is
held in one position, an interesting constellation of pitches result. If, as the score calls for, the mallet
is swept slowly from left to right, the effect is a generally-ascending set of
gestures, but with a local elaboration that greatly enhances the melodic
interest.
4.3 Performance Freedom in the
Context of a Fully-Composed Concerto
Since
the Drum is a fully-configurable instrument, it is up to the composer how it is
used to affect a musical result.
In The Seven Wonders of the Ancient World, it is used in a wide variety
of ways that often cross the boundary where expression meets improvisation. The model that seems to come closest to
the way we worked is that of the
concerto with improvised cadenzas.
The programming of the Drum is where the composer and performer
meet. The composer provides a
virtual world or language in which the performer can express himself. The freedom is not limited to
unaccompanied passages, but appears often in conjunction with the
orchestra. In such cases, the
composer was especially careful to guarantee that no undesirable
orchestrational collisions could result.
For
example, in "The Colossus of Rhodes", the piano plays twelve simultaneous
trills. One trill is considered
"selected". The selected
trill is chosen continuously according to the performer's left hand X
location. The speed and
loudness of the selected trill corresponds to the left hand z location as the
hand approaches the surface, the trill speed and loudness increase. The right hand controls the speed of
the non-selected trills. The score includes passages where the approximate
range of the selected trill pitch isspecified, along with the dynamics, while
it is up to the performer to select an appropriate trill pitch. In other passages, the performer has
freedom to improvise in the context of this highly-constrained "trill
world."
5 Summary and Acknowledgments
Mappings
from percussive and continuous gestures to piano sound production make possible
a new realm of piano music. The
approach of using quasi-improvisational scenarios for the Radio Drum part can
allow a composer sufficient influence over musical materials, while
simultaneously allowing the performer freedom to realize the potential of his
instrument. Work on this piece was
supported in part by a Collaborative Composer Fellowship fromthe N.E.A., a
federal agency. Further support was provided by the Banff Centre. Special thanks to Yamaha for providing
the Disklavier used in developing the piece. Thanks also to Max Mathews and Bob Boie for their marvelous
inventions.
6 References
Boie,
R.A. et al. Gesture Sensing via
Capacitive Moments. Work Project No.311401-(2099,2399) AT&T
Bell Laboratories,
1989.
Brant,
H. Personal communication, 1980.
Jaffe,
D. and A. Schloss. The
Computer-Extended Ensemble.
Computer Music Journal, 1994 .
Jaffe,
D. Ensemble Timing in Computer
Music. 1985. Computer Music Journal,
9(4):38-48.
Jaffe,
D. and A. Schloss. Wildlife. CDCM
Vol. 15, 1994
Jaffe,
D. Terra Non Firma. Ibid.
Jaffe,
D. and A. Schloss. The Making of
Wildlife. Proc. of the 1992 ICMC.
Mathews,
M.V. and A. Schloss The Radio Drum as a Synthesizer
Controller, Proc.ofthe 1989 ICMC.
Mathews,
M.V. The Conductor Program and Mechanical
Baton. 1988. Current Directions in Computer Music,
MIT Press.
Schloss,
A. and D. Jaffe. Intelligent
Musical Instruments...
Interface, 22(3):183-1
93.