A Computer-Based Approach to Teaching and Learning Complex Rhythms
Bruce Dalby, University of New Mexico
This century has witnessed a steady increase in the rhythmic complexity of certain forms of serious art music. Solo literature for percussion, in particular, has reached a level of sophistication unimaginable a hundred years ago. So difficult is some of this material that performers and teachers question the feasibility of learning it through conventional methods of audiating beat and subdivision. Marshall McLuhan stated that technologies tend to reverse themselves. Perhaps the "technology" of written musical notation has outrun itself in reaching its current apex of complexity, creating a need for new approaches to advanced literature.
Non-literate musical cultures may provide a useful clue to the solution to this problem. North Indian tabla drumming, for instance, is taught through a rote-imitation process. The master serves a dual role: he provides an aural model of correct performance and then evaluates the accuracy of each attempt of a given rhythm by the disciple. A similar rote procedure may be effective in teaching and learning contemporary solo literature for percussion and other instruments.
Precise sequencing and timing of virtually any set of musical events are possible with today's microcomputer and MIDI (Musical Instrument Digital Interface) technologies. Current high-end music notation programs, for example, include a "fancy tuplet" feature that enables the user to superimpose almost any subdivision scheme over any musical duration. By layering multiple tracks in this fashion, musical passages of virtually limitless complexity are created with relative ease. Likewise, selecting a section of any length for repetitive drill is a simple matter. The software thus performs in a manner analogous to the first function of the master in the teaching relationship described above, namely, providing an aural model of correct performance. These programs, however, have no way of fulfilling the second role of the teacher, that of evaluating the accuracy of each attempt. Although a perfectly accurate rendition of a musical passage is available to the student in aural form, this type of feedback doesn't necessarily lead to insight as to the specific nature of temporal inaccuracies in her own playing. In addition, the high monetary cost and time necessary to learn powerful notation and sequencing packages may be an impediment to their effective implementation in teaching situations.
Music education software developers have investigated the idea of providing visual feedback about the rhythmic accuracy of students' playing. Ibis Software's Rhythm Ace, for instance, displays rhythmic relationships graphically, using horizontal lines on the computer screen to represent durations. The student sees a picture of her attempt displayed directly underneath the correct rhythms. This feedback leads, presumably, to increased awareness of rhythmic strengths and weaknesses and how to practice for greater accuracy.
The limitations of Rhythm Ace correspond closely with the capabilities of notation programs:
1. There is no provision for entering complex tuplet groupings.
2. Rhythms play on a single pitch, without melodic content.
3. The length of exercises is limited to a single screen.
4. The user cannot select a segment of a longer exercise or piece for concentrated, repetitive practice.
This paper describes a software sequencer, Rhythm Coach, specifically designed to combine the strengths of both types of products described above in a single package. Like today's expensive notation programs, Rhythm Coach provides an intuitive interface through which the user can quickly and easily enter complex passages and hear them played perfectly through any MIDI compatible synthesizer. Like Rhythm Ace, it also affords precise feedback about the student's attempts to perform with rhythmic accuracy.
Description of the Program
Rhythm Coach is a Hypercard stack that runs on the Macintosh computer. The edit screen, where users enter musical event data, is shown in Figure 1. The editing process is as follows:
1. Specify the number of tracks, to a maximum of three. In most cases, a given track would consist of a discrete melodic line with its own beat and subdivision scheme.
2. Indicate which note (eighth, quarter, or half) will function as the basic beat. .
3. Create a measure map (for a given track). The measure map indicates the lengths of macrobeats in basic beat units and the basic subdivision of each macrobeat. Information in the Measure Map field for each macrobeat includes the measure number, beat number, size of the current macrobeat in basic beat units, and how many of a particular type of note fit in that period of time. Line 6 in the Measure Map shown in Figure 1, for example, indicates a macrobeat which is beat 1 of measure 2, is two basic beats in duration (a half note, that is), and includes five eighth notes (2:1 2 = 5 x 1/8 ). Figure 2 shows the Edit Measure Map card. Entering the information for each macrobeat is a simple matter of clicking on three buttons: once to select which note functions as a macrobeat (musical note buttons on the left), once to indicate the subdivision (center radio buttons), and once to indicate what note value represents a single subdivision of the larger macrobeat (musical note buttons on the right).
4. After entering information into the Measure Map from the Edit Measure Map card, the user returns to the main edit screen to enter notes for that track. The process is in two steps: 1 ) specify the note through either MIDI or keyset input, and 2) click on the icon of the correct note value. Rhythm Coach automatically determines the note's length in relation to the current macrobeat. If the current macrobeat is a half note, for example, that macrobeat is worth five eighth notes, and the entered note is a quarter note, the finished event entry would have a duration of 2/5 of the current macrobeat. The actual temporal duration of the note would depend on how many basic beats are in the current macrobeat. Fields near the top of the screen display information about the current measure, macrobeat, and beat fraction.
Other features of the main edit screen include:
1. Hear segment. The user may select a segment of any size for repetitive drill.
2. Tempo changes. Ritards and accelerandos can be entered at any place in the event list.
3. MIDI metronome. The user may select metronome beats according to basic beat units, macrobeat units, or no metronome.
4. Variable tempo. A basic tempo for each piece is chosen when the piece is created, but that tempo can easily be adjusted up or down at any time.
After entering note and rest information for a given passage or piece, the user goes to the practice card, shown in Figure 3. Here the program displays a graphic representation of note, beat, and measure information for whatever measures comprise the current segment. The first four measures of a piece are shown in Figure 3. The small vertical marks in the "Correct" section of each row represent the precise times at which notes begin. When the user first comes to the card the "Attempt" area at the top of each row is blank. This is where his attempts to play the passage are plotted. Visual feedback is rapid. Each time the user clicks the play button, the program begins recording the timing of any incoming notes. At the end of the passage (or when the "Stop" button is clicked) any notes played are immediately plotted, providing precise feedback about the student's rhythmic accuracy.
The practice card offers considerable flexibility regarding the way in which elements are played and plotted. Any combination of tracks may be plotted (notes in different tracks are represented by markers of different sizes. Likewise, the user may choose which, if any track to hear while practicing a passage. Count-offs of two or four may be selected, or no count-off at all. The metronome can be heard according to basic beats or macrobeats, or it can be turned off.
Conclusion
Rhythm Coach was originally conceived as a way to assist students in learning to play musical passages of extreme rhythmic complexity. Students in the percussion studio at the University of New Mexico will use it as an aid in their learning of literature that is difficult to learn through conventional practice methods. It may also prove, however, to be useful in analyzing and refining performance of more commonplace rhythms.