Continuo, part I
The musical practice known as continuo playing was an integral part of ensemble music from about 1600 until about 1750—the dates that we assign to the “Baroque Period.” Indeed, it makes a lot of sense to define the Baroque specifically as the era in music history when continuo playing was the norm. During that period, almost every work of music that was not a solo keyboard or lute piece included a continuo part. (Exceptions, such as pieces for unaccompanied violin, or lute songs, probably amount to no more than five percent or so of the repertoire.) This includes sonatas, trio sonatas, works for larger instrumental ensembles, songs, cantatas, Masses, operas, and oratorios—arias, choruses, recitative, and so on. The practice of writing continuo parts certainly persisted into the second half of the eighteenth century—the “Classical” era—but became less common, less mainstream, less central to what was going on in the world of musical performance. Continuo died out early in the nineteenth century. (Mendelssohn, however, still included continuo parts in some of his sacred music in the 1830s.)
What is continuo?
This month’s column will begin to answer that question, or, really, to address it in ways that I hope will be helpful to students. (Of course if any of us as organ teachers have students who have already studied continuo fairly deeply or who have specialized in it, then those students will already know or understand more than I am going to write about here. So this is, at least directly, for everyone else.) Next month I will outline in a fairly basic form my own approach to teaching the nitty-gritty practical side of creating and performing continuo parts at the keyboard, starting with how to read the notation, and I will discuss how to deal with the artistic choices that creating such a part entails.
I actually have a memory—a distant memory by now—of my own first encounters with the word “continuo.” These happened at a number of chamber music concerts on the Yale campus that I heard in the late 1960s, as a youngster just getting interested in music. There were pieces described as “Sonata for violin and continuo” or “Trio Sonata for violin, oboe, and b.c.” or other such phrases. (The word “continuo” and the expression “b.c.” are both abbreviations for basso continuo.) I noticed that some of these pieces turned out to have the wrong number of players, that is, a trio sonata might have four people playing. I still remember a sort of “Twilight Zone” feeling that I got looking at descriptions in the programs that seemed not to be written in any normal language that I could discern and that seemed not to correspond to what I was seeing on the stage. I vaguely remember asking someone (my father?) what it all meant and his not knowing either. I believe that we considered the possibility that it might be some sort of misprint.
I still get the very basic question—“What does ‘continuo’ mean?”—both from audience members at concerts and from (new) students. The basic answer is this: a continuo part is a line of music, mostly in the range of the bass clef, that forms the lowest part of the texture of a piece, that is meant to be played by one or more instruments in unison, and that is meant to be supplemented by notes not written by the composer: chords or bits of melody supplied by one or more of the performers. The choice of instrument or instruments is not, except in rare cases, specified by the composer. The performer’s process of deciding what “notes not written by the composer” to add is called “realizing” the continuo part. In the Baroque period this was almost always done by actual improvisation. Nowadays it is done either by improvisation or by planning and writing a part in advance.
Elements of improvisation
Part of this picture is that Baroque composers—from the most iconic such as Bach or Handel through thousands of others whom most of us have never heard of—expected the actual notes of their pieces to be different from one performance to another, with part of the note picture composed not by the “composer” but by any given performer. This often blows people’s minds: we associate the notion of a performer writing part of the music with certain kinds of twentieth-century experimental art—participatory or aleatory music. The music of the Baroque often seems to embody an opposite principle, one of rigorous form, often expressed through complex counterpoint.
Sometimes the simple act of becoming aware of the nature of continuo accompaniment can reset a student’s sense of what Baroque music is all about, away from structure and control towards spontaneity and change, and, in a sense, away from the composer towards the performer. Of course, it is also true that a lot of Baroque keyboard and lute repertoire was improvised from scratch. In fact, we assume that something close to all of the keyboard playing that took place in the Baroque era was improvisation. However, in a funny way, improvised repertoire suggests a less radical departure from composer control than continuo accompaniment does, in that with improvised repertoire the performer is the composer.
Of course with continuo accompaniment, the additions to the music put in place by the performer exist within certain well-defined bounds—and we’ll come back to that below. However, it is clear from comparing all of the recordings of just about any piece of Baroque music that the differences between one player’s version of the keyboard continuo part and another’s can make a huge difference in the overall effect of a piece. And, again, this is something to which composers routinely ceded control.
The key to accompaniment
So why did composers give up control over a crucial aspect of their pieces—consistently and over a period of more than 150 years? I believe that the answer lies in the nature of accompaniment and in the nature of the instruments used for accompaniment during those years. There is a lot to say about accompaniment, whether of the continuo variety or of the obbligato variety, as represented by such things as Schubert song accompaniments. Great accompaniment requires all sorts of subtleties and sensitivities. However, one thing is absolutely fundamental, without which accompaniment runs the risk of being not just artistically sub-par but really grotesque: the ability to vary dynamics in a way that tracks what the other instruments or voices are doing. Without this basic ability an accompanist constantly runs the risk either of drowning out the other instruments or voices or of failing to support them adequately. If the keyboard instrument is one on which dynamic variation is inherently possible, say, the piano, then a composer can write accompaniments in which the note picture is fixed once and for all, that is, written by the composer as part of writing the piece. If, however, the accompanying instrument is, like the harpsichord or the Baroque organ, not capable of inherent dynamic flexibility, then it is important that the performer be allowed to change the number of notes being played at any one time in order to change the effective dynamics. A Schubert song piano part played as written on a harpsichord would be an almost pathetically ineffective accompaniment. It would fail to support a singer with a robust or just plain loud voice, it would drown out or at any rate compete too much with a light or delicate singer, and it would fail to reflect or mirror or complement nuances of dynamics executed by any singer. However, it is possible, in a piece with continuo accompaniment, to make the keyboard part of a whole passage louder or softer by choosing to play a thicker or thinner texture of added notes and chords. It is also possible to place an accent on certain notes or beats while allowing other notes or beats to be unaccented, again by actually playing more notes, a thicker texture, on the accented moments and fewer—or no—notes elsewhere. It is possible in the same way to respond appropriately to crescendo, diminuendo, and other dynamic gestures that singers or other players carry out.
(I should mention that years ago I subscribed, without having really consciously thought about it, to the absurd idea that Baroque composers wrote continuo lines rather than obbligato accompaniments because their composing skills were too rudimentary to concoct complex accompaniments. In this story line, the development of “real” keyboard parts for chamber music and songs in the second half of the eighteenth century was a kind of progress, akin to the scientific progress that—genuinely—characterized that era. The notion that composers who wrote the elaborate, complex counterpoint that was routine in the seventeenth century couldn’t have written compositionally successful keyboard parts for their songs and chamber music is indeed absurd. However, I think that some people do fall into the trap of assuming some such thing, as we have a general tendency to believe that the passage of time brings progress. We feel that people of old simply couldn’t do a lot of what became normal or easy later on.)
Some confirmation of the notion that the continuo texture really did serve the purpose I have described is found in this: when composers in the Baroque era wrote song accompaniments intended to be played on an instrument that had dynamic flexibility—namely the lute—they did write obbligato accompaniments. This gives us the lute song repertoire, with all of the notes of the pieces written by the composers.
Continuo instrumentation
The instrumentation of a continuo part is flexible. This is one of the reasons that the part is given the somewhat abstract name that it has. It is not the “organ” part or the “harpsichord” part. It was customary for a continuo part to be played by at least two instruments: a bass melody instrument playing the continuo line itself and a chordal instrument—keyboard or lute—also playing the written continuo line, but adding the extra notes and chords that we have been referring to. It was also common for more instruments to be involved. Typical combinations include cello and harpsichord; cello and organ; bassoon and organ; gamba, organ and lute; cello, double bass, and harpsichord, and so on. This flexible instrumentation is the source of my old confusion about the number of players on stage. A “solo” sonata can have anything from two players to four or, somewhat atypically, five; a “trio” sonata might indeed have only three players, but more usually will have four, often five or more. A continuo group for a large-scale piece—a cantata or oratorio or orchestral piece—can easily have half a dozen or more players.
Regardless of the exact instrumentation—which, again, is almost always at the discretion of the performers—the structure of the part is the same. The line actually written by the composer, the bass line, which is the foundation of the harmony of the piece, is played in unison by all of the instruments participating. Notes that are added by a keyboard player or lutenist are played only by that one instrument. Thus, most of the time it is the bass line itself that, within the texture of the continuo part, is the most prominent, with the added notes always somewhat in the background. (An organist performing a continuo part without the help of a melodic bass instrument should bear this in mind in planning registrations.)
Figured bass
So, if a keyboard player performing a continuo part is supposed to add notes to the texture, how is the choice of those notes to be made? The first answer is that they must be notes that are consistent with the prevailing harmony, and not in conflict with what is going on in the written parts. The player needs to have a way of knowing what that prevailing harmony is. This can be achieved by ear, for players who are skilled at such things, or by studying the score. However, this is also where the figures that are often written under the musical notes of a continuo part come into play. Those figures are in effect a short score of the harmonic picture of the piece. To some extent they indicate what notes the other instruments and voices are actually producing. Beyond that they indicate what other notes are consistent with the harmony implied by the notes being played or sung or by the harmonic logic of the piece. The system of figures is a system of abbreviations. As mentioned above, I will go into detail about how to read figures next month. The figures—or more accurately the figures in conjunction with the printed notes—never tell the keyboard continuo player what to play. They tell the player what the range of possibilities is for notes to be played, or, to put it another way, they tell the player by implication what notes are not available to be played. In many pieces the abbreviated nature of the figuring is taken to its logical extreme, that is, there are no figures. This in no way implies that the player is not meant to add notes and chords. It is not a situation in which anything different is going on. The player has to rely on other things—the listening and studying mentioned above—to glean the information that figures could have given.
From within the constellation of notes that would be acceptable to play at any given moment, then, how can a player make specific choices? This is both the most difficult part of continuo playing and its artistic/interpretive component. It is actually rare that a keyboard continuo player has to play notes—any notes—for the purpose of providing or filling out the harmony. This is true for two basic reasons. First, in most passages of chamber or vocal music, most of the harmony is provided anyway over the course of a beat or two, amongst all of the instruments or voices. (Clearly the thicker the texture, the closer this will come to being completely true.) Second, there is nothing in the rules or expectations of tonal music that says that every part of the theoretical harmony has to be present at all times.
Instead, choices about exactly what notes to play (to add) at any given point are based on considerations that have nothing to do with completing the harmony as such. These are considerations of texture, volume, accent, rhythm, pulse, shaping of phrases or sections, and, very practically, both helping and not hindering the other performers. They all stem from the basic fact that adding more notes makes things louder and adding fewer notes or no notes makes things quieter. Thus “thicker chords on accented beats” is a simple but valid guideline, and there are plenty of others. More on this next month.
