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Singing in Tune The anatomy of choral intonation and the techniques for improving it

October 3, 2011

“Through pride we are ever deceiving ourselves. But deep down below the surface of the average conscience a still, small voice says to us, something is out of tune.” - Carl Jung

Of all the nightmares that can disturb a choral conductor’s sleep, the one concerning the opening section of the “Pilgrim’s Chorus” from Wagner’s Tannhäuser must be among the most feverish. “There is none among us that can conduct or listen to that piece without muscles tensing as each passing measure leads to possible disaster,” said Tim Seelig, artistic director of the San Francisco Gay Men’s Chorus and former conductor of the Dallas-based Turtle Creek Chorale.

The bad dream begins a few seconds into Wagner’s slow and intense introduction scored for a cappella male chorus, as the thickness of the men’s harmonies gradually yet palpably drags the sound southwards like a crank-operated gramophone recording in its final sonic throes. By the time the orchestra enters around the two-minute mark, the chorus director’s muscles are as tense as the strings on Tannhäuser’s harp, for Wagner never intended this section of his opera to be performed in multiple keys.

The human voice is one of the most pitch-flexible of instruments. Our voices can vary tuning with no restraints and make adjustments in the middle of a performance without needing to retune like most other instruments. Yet intonation is undoubtedly one of the most pervasive problems facing singers. Few people really notice when a vocalist sings in tune. But poor intonation can clear a concert hall.

The issue is troubling enough for a solo singer. For an ensemble composed of multiple abilities and personalities, wayward tuning can be even more difficult to recognize and correct. Lacking the intonation “barometer” provided by an accompanying piano or other instruments, a cappella groups can easily slide or spike without knowing it. And even accompanied singing can fall prey to erratic intonation. It only takes a mismatched vowel, a bar or two of overblown vibrato, or an acoustically challenging room to render a passage flat or sharp.

The Anatomical Basics

At the physiological level, human beings are equipped with varying degrees of sensitivity to pitch. According to Dr. Psyche Loui, an instructor in neurology at Harvard Medical School who has done extensive research on pitch, people who possess a strong connection between the parts of the brain dedicated to matching pitch and perceiving feedback are better able to sing in tune than those with a weaker or absent link. “People who are tone deaf have a smaller or missing branch between the areas of the frontal lobe used for producing sound and the temporal lobe, which is important to perception,” she said.

There are therefore at least two fundamental ways in which the brain needs to work to stay in tune: “One is storing a kind of template that you need to move the vocal cords in a certain way to get a certain sound,” Loui said. “The other is being able to hear yourself sing.”

With these anatomical basics in mind, it follows that most of the reasons that choral music experts cite to explain why choruses go out of tune fall into two categories―producing sound and hearing it.

Not being able to hear oneself or others sing is a major issue when it comes to tuning. “Clearly, it's impossible to tune if you can't hear the singers around you,” said Karen Thomas, artistic director and conductor of Seattle Pro Musica. According to Thomas, there are many possible causes for this, such as the acoustics of a rehearsal or performance space and the specific placement of individual singers within the group. “Singers can often hear the whole better when in mixed quartet formation,” Thomas said. “Likewise, an imbalance of singers’ volumes can create a situation in which those with softer voices are unable to hear themselves, or can only hear a few overly-loud singers near them.”

Feedback is such a subtle mechanism that sometimes an audible hum from a lighting fixture is enough to wreak havoc on an ensemble’s careful intonation. But while a chorus might not be able to do much about the various mechanical and acoustical challenges of a room, there are many factors that cause meandering intonation that are well within the singers’ control.

These factors mostly fall under the category of vocal production, and more often than not, out-of-tune singing can be blamed on sub-par technique. “Any lack of rhythmic vitality and precision will cause intonation problems, as will poor singing posture, lack of breath support, and lack of mental and aural concentration,” said Pearl Shangkuan, director of the Grand Rapids Symphony Chorus. “It also takes everyone working toward producing the exact same vowels at the exact same time to tune well.”

The Tools for Fine-Tuning

Being acutely sensitive to unwelcome leaps and dives in pitch, chorus directors and pedagogues use a diverse set of tools to improve intonation. Techniques range from simple breathing and diaphragm support exercises to making micro-adjustments to vowels in certain parts of singers’ registers to help make specific words in a song sound more in tune.

One fundamental goal shared by all choral directors in the struggle to perfect intonation centers on improving choristers’ listening skills. “I build chords from the bottom up to get the singers to listen to the correlation of intervals,” said Ragnar Bohlin, director of the San Francisco Symphony Chorus. “I often ask the singers to change places and mix up,” said Seelig. “This absolutely forces the group to listen.”

Conductors frequently use warm-ups aimed at improving singers’ listening skills, drilling them on whole tone and chromatic scales, arpeggios, and chord clusters among other musical devices. “I love the Robert Shaw warm-up in which the choir takes 16 beats to move up or down a half-step, moving just a few cents per beat, all attempting to move at the same small increments precisely together,” said Thomas. “It's virtually impossible to do this exactly, but it certainly wakes up the ears!”

No matter how idiosyncratic these activities seem, they all exist in the service of rehearsing and performing repertoire. Every piece of music, regardless of its style and genre, poses particular intonation challenges on singers. Poor intonation may be more immediately apparent in monophonic music because of the transparency of the texture. But it’s equally hard to sing in tune on a fast atonal piece with difficult leaps.

A chorus working on music that veers away from the classical western convention of “equal-tempered” tuning (where each of the 12 half-steps of the octave scale is exactly the same distance apart) has to adopt and hone particular strategies for precise tuning. The members of the France-based Harmonic Choir―a chorus founded in 1975 by the American composer, singer, and meditation teacher David Hykes that specializes in overtone singing―often listen to their pitches over headphones to achieve their amazingly complex tunings.

Meanwhile, Anonymous 4, an a cappella vocal ensemble that specializes in Medieval repertoire, focuses its intonation efforts on the perfect fifth―the only consonance allowed in Pythagorean tuning, one of the oldest known methods of defining musical pitches that informs the performance of much pre-17th century music in the west. In Pythagorean tuning, all perfect fifths must be in tune, even at the expense of the other intervals. As a result, the perfect fifths sound resonant, while the thirds are unexpectedly brighter and more complex than in the equal temperament we’re used to today. “It simply sounds best if we tune the fifth just a little bit higher than it is tuned on the piano,” said Marsha Genensky, who sings with Anonymous 4. “Our tuning starts with this bright fifth. We then work outward from there, whether we are singing monophonic music or music in multiple parts.”

When to Go with the Flow

Hearing slight deviations in pitch and devising techniques to correct them can be incredibly subtle work. But just as there are occasions where it pays for a conductor to simply tell vocalists that they’re singing sharp or flat in a particular spot to instantly rectify matters, so there are times when it’s better to let a chorus fall or rise a semi-tone or two than attempt to resist the herd mentality. This is particularly sensible advice for choral singers with perfect pitch. “I don't feel I can do very much of anything as a single singer to influence the pitch group-think during large ensemble performances,” said Cecelia Lam, a San Francisco-based vocalist with perfect pitch. “If pitch sliding occurs, I usually slide along because holding my ground just makes me sound out of sync with the choir.”

As painful on the ears as tuneless singing can be, choruses often get away with freewheeling intonation. The reality is that some audiences are completely impervious to defective pitching. Ultimately, if a chorus sings with commitment and overall musicality, flawless tuning may not be the most important element of the performance. Indeed, some choral professionals even welcome the times when choruses slip. “Imperfection is being human,” wrote Chris Rowbury, a chorus leader and the founder of WorldSong, a community choir based in Coventry, England, in his blog. “When listening to a choir, it is the small imperfections, the differences in vocal quality and tiny errors in tuning, that give the overall texture and richness of sound that we all love.”



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