Vacillare
Giovanni Tosi, in his treatise on singing titled, "The Art of the Florid Song," published in 1736, uses the term "vacillare" to describe the effect of vacillating in the melody from being before the bass to lagging behind the bass. He states "the singer should endeavor to sing before the beat or after the beat and never with it." Astonishing!!!!! Today, almost no classically trained singers do this because they are usually mercilessly censured for doing so. Yet this practice of singing using the vacillare technique was in common use by all the most popular singers in the 20th century…singers like Barbara Streisand, Judy Garland, Frank Sinatra, Bing Crosby, and Maria Callas.
It is perhaps a false notion about the way singers are trained in Bel Canto that accounts for the general inability of singers to sing using vacillare. They are habitually trained to produce as beautiful a tone as possible; that's the false notion with which singers are preoccupied. That's the root of the problem. Bel Canto means "beautiful singing," not "beautiful tone". Tosi says of vacillare that it "is one of the most beautiful effects in music." The vacillations he describes give the synesthesis technique a feeling of flow and freedom...a most beautiful effect indeed.
It is interesting to realize that J.S.Bach, in manuscripts of his keyboard pieces, uses vacillare just as Tosi recommends. When you listen to the next YouTube post below, watch the manuscript as it scrolls by. Careful observation of his manuscript reveals that the vertical alignment of the notes of the right hand either precedes or follows the notes of the left hand. About 60% of time, the right hand notes precede the left hand notes, and about 40% follow the left hand. To suggest that Bach was doing this either unintentionally or that he had problems with vertical alignment is preposterous: Bach was probably the most intentional of all composers, especially when it involved music, and he had no problems aligning notes in orchestral scores.
Forqueray, in his published arrangement for harpsichord of his fathers Pieces for Viola da Gamba, gives instructions that the player play the music exactly as it appears on the printed page. The pieces that follow show the right and left hand notes being vertically non-aligned even to the extent that some whole notes in the left hand appear in the middle of the measure!!
And Giulio Caccini, in his "Nuove musiche e nuove maniera di scriverle" ("The New Music and the New Manner in Which it is Written," Florence, 1614), suggests something very similar to vacillare when he writes: "Sprezzatura is that elegance given to a melody by several technically-incorrect eigths or sixteenths on different tones, technically-incorrect with respect to their timing, thus freeing the melody from a certain narrow limitation and dryness and making it pleasant, free, and airy, just as in common speech, where eloquence and invention make affable and sweet the matters being expounded upon."
Does all this mean that using a synasthesis technique in the form of vacillare is easy? Certainly not. Proficiency requires practice. It is even harder is to develop the ability to think and imagine all the voices one is playing, be they 2 or 5 at once, so that each voice is sung both extremely expressively and independently of the other voices. But it can be done. We coached an organ student who was unable to independently play all voices of a 4 part Chorale Prelude from Bach's Orgelbüchlein and within 20 minutes he was singing and playing all four voices independently and expressively throughout the entire piece-- we know from experience that it is possible for all musicians to learn to do this. Furthermore, Bach's music cannot be heard as it was intended to be heard unless one masters this technique.
Take the trouble to find other recordings of the same piece and discover if those performers were able to create this feeling of true independence of voices.
Application: Always play with one hand leading the other and vacillate between which of the two hands leads. Try learning to play with the right hand leading the left...it gives the music a natural effortless forward motion and freedom in the sound. Give up trying to be together in ensembles. The exception to this is when one arrives at the end, when a simultaneous concurrence of the voices tells the brain that the music has come to an end.
Application: Sing expressively each and every line or voice as independently as possible of the other lines or voices. Prevent yourself from lapsing or dropping your attention to any line or voice; or the listeners will hear the lapse in attention and cease to pay attention.
Application: In ensembles, vacillate between having the upper voice lead the lower voice and the lower voice lead the upper voice. This vacillation needs to follow the logic of the musical lines and structure. When the upper voice leads, the music soars. When the lower voice leads the music lingers, resisting forward motion.