Improving String Tone

Anne Mischakoff | April May 2023

String Clinic

Editor’s Note: This string clinic is an Instrumentalist Classic, originally published in the September 1992 issue.

Conjuring up memories of Itzhak Perlman playing with heart and soul, a person might attribute a good string tone to vibrato and expression. Perlman’s throbbing intensity could seem out of place in a large ensemble though, where basic pure tone often blends better. Most players consider bowing the primary component in producing a good string sound. Some teachers compare bowing to breathing while others compare it to the soul. As breathing sustains life and mostly occurs involuntarily, bowing sustains sound and should be so natural it becomes intuitive.

When people scream, they first inhale to move hot air out of their lungs, across their larynx to the listener. Wind players and singers use more sophisticated methods to support the sound. String players could regard bows as a stream of breath; instead of pressing down on the string with an effect like a glottal stop for a singer, coax the sound using a bow to move the string sideways.

The simplest way to understand string tone production is by plucking an open C or G string to observe its response. Almost 25 years ago Paul Rolland produced a film showing an open string close up and in slow motion when plucked. The string forms an elongated oval as it vibrates sideways, with a visible amplitude. The harder the tug on it, the wider the amplitude and louder the volume. If the plucking is directed upward to pull the string away from the fingerboard, it produces a less reverberant sound; with a strong tug, the string will snap back against the fingerboard, making the sound known as a Bartók pizzicato. Plucking sideways produces a better quality sound with more volume, readily seen by students observing a cello or doublebass when plucked. The same can be seen with a violin placed vertically on a desk with the fingerboard facing them. They should pluck softly and then gradually more loudly to see that as they pluck more vigorously, the string vibrates more widely. This principle applies directly to bowing. Greater volume depends more on bow amplitude and speed than on pressure. Pressing down on a string crushes the sound and impedes the vibrations.

Teachers usually have beginners start with short strokes in the middle of the bow on quarter and eighth notes. Students learn to play short notes with more confidence than long tones; to compensate for this, remind them to use more bow: move the bow faster and with longer strokes. Faster bow speed increases volume and makes tiny instruments sound better. This principle is not limited to students; professional players use more bow for an open, full sound as well as for mellow tones.

Longer bow strokes often tend to go astray, which is why string teachers delay introducing them. The correct method is to bow in what is loosely called a straight line by extending the forearm at the elbow joint about two-thirds of the way to the bow point, pulling the bow forward and away from the body, and slightly in front of it. Extending the forearm produces a good, clear tone through the entire stroke and avoids a strained sound. This extension and contraction of the right elbow is one of the most important techniques in developing a good tone.

From the shoulder joint the arm’s natural swing is a semiarc toward the side and back. The bow, however, should cut across the string at about a right angle to produce a clear tone; students should compensate for the natural arm swing by extending the forearm from the elbow joint as the bow approaches the tip. Reverse this motion on an up-bow when nearing the frog by bringing the bow and hand closer to the body.

Players with longer arms find it helps to hold the instrument further to the left away from the bow arm, while those with short arms bring the instrument closer to the right arm and bow. In the past teachers advised dropping the right wrist when playing at the tip and curving it when playing at the frog, but the prevailing view now is that bending the wrist excessively tends to weaken the tone production by breaking the line between the extended wrist and forearm. Power is greater when muscles are close to their natural resting length, rather than contracted as with a curved wrist; this principle applies equally to using a tennis racket or golf iron.

Playing a long bow stroke is something like steering a sailboat by pushing or pulling the tiller. Teachers monitor a student’s bow direction and placement by checking either the tip or the frog, but players sense direction and angle more by feel than sight. It is simpler to control the angle properly by thinking of pulling in with the ring finger as the bow moves to its frog than by worrying about wrist shape. This inward pulling corrects the alignment while keeping the wrist low and powerful.

By using generous bow lengths, string sections will project a good tone quality and help small-sounding instruments or less powerful players sound better. In contrast, high school students with full-size instruments are physically mature enough to refine control of the tone. However, the consistent use of large amounts of bow restricts the range of dynamics, color, speed, and phrasing; it sounds boring and is difficult to balance within an orchestra. It is better to restrict large bow strokes to forte passages and projecting sound and to use light bowing for an airy soft sound.

Sticking to the middle of the bow, like the middle of the road, is safe but mundane. Even young students can explore using different parts and amounts of bow to vary dynamics and tone color. The phrasing and articulations in Classical period repertoire especially invite varying bow speeds, lengths, and distribution. Experiments with bow length and placement can be part of a warm-up routine. Have students use half the bow length, a quarter, and an inch or two in different tempos while playing scales at the tip, frog, or middle of the bow. A way to improve bow control is the technique of son filé, or spunout sound, playing whole-note scales with each note sustained for 6, then 7 or 8 seconds, progressing to anywhere between 12 and 30 seconds. Add dynamics or hairpin swells, a crescendo or decrescendo on each pitch. These long tones will develop muscle control in playing softly and loudly. Students can also imitate a creaky door by pressing down and bowing very slowly, intentionally forcing the tone until it becomes a noise. The experiment demonstrates the relationship between bow speed and pressure, and delineates the line between good sound and noise, with only a minimal risk that students will continue making the noise afterwards.

In recent decades, teachers are more aware of the risks from unnecessary tension and avoid language that causes or encourages it. The bow grip is called bow hold and is sometimes compared to tenderly clasping a bird or stroking velvet. The pendulum of bow strokes has swung from too rigid to sounding like fluff. For a centered sound with a core hold the bow tightly enough to feel the stick and maintain contact with the string as it slips sideways in its vibrations. Larger arm muscles should move freely and without tensing unnecessarily. Jascha Heifetz was a master of this balance in bowing; up close his sound was a little rough at times, but it projected smoothly in a large hall.

Large muscles, such as the trapezius, deltoid, and biceps, supply the power, while the smaller hand and forearm muscles focus bow direction like a steering wheel. As the arm extends, the index finger presses downward (called pronation) to drive the stroke. Pressure at the tip should be greater to compensate for the bow’s lightness, and the index finger more angled to add leverage. Bowing with the lower part of the bow puts more weight on the string because the frog is heavier. The little finger can compensate by reducing bow weight on the string. The thumb helps also, pivoting the stick slightly away to tilt the bow until less hair is on the string. String players should learn that the thumb acts on the bow as a fulcrum with either the index or little finger depressing the stick. This leverage is called getting into the string because the bow hair seems to contact the instrument string so well.

Orchestral music has many string passages with sustained tones that seem to thicken the texture too much. In Baroque continuo parts the walking-bass line or inner voices sound better with more space and reverberation between notes. Students should listen to doublebasses and cellos playing pizzicato to hear how slowly the sound decays. All strings can play staccato notes with resonance by adding a little vibrato as the pressure on the bow is released. The release and reverberation do wonderful things for orchestral balance and allow the accompaniments to be distinct without covering the melody.

Besides speed and pressure the contact point on the string affects tone, timbre, and dynamic. Because low strings are thicker and heavier than upper ones, bow C and G strings slightly closer to the fingerboard for a response comparable to the D, A, and E strings. For a soft, floating sound, bow near the fingerboard or sul tasto; for a shrill, glassy sound play very close to the bridge (called sul ponticello). Bowing near the bridge, a slower bow speed and slightly more pressure help produce a forte sound. Conversely, moving the contact point nearer to the fingerboard with less pressure and slightly more speed softens the tone.

When bow speed is constant, changing the contact point alters the sound quality. There are formulas to describe these changes to older students, who appreciate more analytical explanations. Ultimately players should practice until adjustments follow intuitively. With careful listening string players in time will instinctively choose the right combination of bow speed, pressure, and contact point.

Professionals and more experienced players know many tricks about which part of the bow and string to use. Double-stop chords sound better closer to the fingerboard with little pressure, using the tautness of the frog or tip of the bow. Most students have only a vague awareness of the gutteral, raucous sounds double-stops have when played with too much pressure and too little motion. I changed that sound at my father’s insistence, and I have yet to encounter a student who did not need this lesson. Usually younger students and lazier professionals are reluctant to expend the effort on playing close to the frog, breaking chords quickly and continuing the bow’s path out and off the string.

Younger students are often lazy about holding up violins and violas. As the instrument droops, the bow slides onto the fingerboard and produces a fuzzy, weak tone, and players are cramped for space. Sometimes students have insufficient room to bow, or music stands are too low to encourage good posture, but stands also should not obstruct the visual line to the director. Sometimes just holding up the scroll for a student conveys the message.

String sections that bow consistently in speed and direction have an open and pleasant sound that projects. It should become a habit to look at section leaders. The principal player of each section, with suggestions from the conductor, should set up-bows and down-bows and which part of the bow to use. If most players are at the tip to play softly and a few bow in the middle, the effect is diffused.

Most students and 99% of professionals consider marking up-bows and down-bows a nuisance, with the few exceptions being players who enjoy determining them for their sections. The bow weighs less at its tip than the frog, at least for the first third of a stroke. Metal, tortoise shell, and ebony add to the frog weight, and gravity pulls the bow faster for a stroke beginning at the frog. By starting with a down-bow, the sound will be heavier and louder than starting with the bow tip. The frog is useful for emphasis, short attacks, downbeats, clunky sounds, and longer staccatos. If an indiscernible attack is preferred, an up-bow allows string sections to slip into a note without an edge to the sound.

To develop bow control, practice setting the bow at the frog, tip, and middle without sound by approaching the string gradually and slowly. Since the 1930s teachers and writers have likened this to an airplane approaching a runway. Perhaps it is time for an analogy with roller blades or scraped knees. Another way to minimize a bouncing or edgy bow when starting a note at the frog is by consciously inhaling and tilting the bow so less hair contacts the string for a lighter stroke.

A string section that plays out of tune has a muddy tone that does not project well. Performers with good intonation are usually those who tune open strings frequently. The quality of an orchestra correlates to the frequency with which players check open strings. Tuning open strings is the quickest way to improve the pitch of stopped notes. It is amazing how often string players will carefully tune the A string but pay scant attention to the other three. Conductors will encourage this behavior by not allowing enough time for complete tuning. Violas and cellos should verify that the low C is high enough to blend with the violin E strings.

Suzuki tonalizations are fine warm-ups, perhaps even better than scales because they begin with a broken chord so the ear hears the key with sympathetic vibrations against open strings. They are somewhat similar to playing an overtone series and make good rote material to begin a rehearsal. Suzuki books include them at different levels, beginning in the major mode, progressing to the minor mode and higher positions. Most students play more in tune after beginning the hour with these exercises.

Like adults, students tend to think they are playing in tune while their stand partner is not, but there is no shame in adjusting; it shows a keen ear and good musicianship. Some young players are genuinely surprised to learn that it is proper to adjust intonation on a sour note instead of holding on to it unless lightning strikes. Tuning and warm-ups, whether on unison scales or in harmony, should be played softly to hear subtle intonation differences.

Bach chorale arrangements are excellent intonation material. Tune the harmonic root of each chord, adding players with an octave of the root and retuning. Add the perfect fifth next because poor intonation is more obvious on perfect intervals, and save any thirds or sevenths for last because intonation on these is open to the most disagreement, and the ear is more tolerant here than with perfect intervals.

Du Friedefürst, Herr Jesu Christ, BWV 116

Bach chorale with suggested order for tuning pitches. Notice at fermata that because E is held, A is tuned from it (perfect interval).

Practicing octaves can improve intonation because violinists and violists use an open string plus a third finger or a first plus a fourth finger on adjacent strings, forming a good hand position. While most violinists and violists regard the little finger as the hardest to tune, the third finger is probably even more difficult, having less independence and more room for error than the fourth.

If directors suggest using open strings except when they would be too strident or exposed in a passage, a section will achieve more resonant tone and better intonation. The four open strings are tuned, and their octaves, primes, and perfect intervals will vibrate sympathetically and add a slight ringing to the tone. Open strings are helpful for young ensembles, but students should strengthen the fourth finger when practicing.

Some students do not cover the string sufficiently when stopping notes. Using the center of the fleshy pad, a finger should depress the string fully against the fingerboard but without a vise-like grip. Use the portion of the flesh away from the nail instead of contracting the fingerjoints into a square, which looks neat but hampers vibrato and clarity. Only when the finger shortens the string cleanly will the tone be clear.

Vibrato warms the string tone and may mask a small degree of poor intonation. Some students avoid using vibrato because it seems difficult and troublesome; indeed it involves the intuitive coordination of 14 pairs of muscles. As students advance, they should experiment with various speeds of vibratos to enhance the interpretation and tonal color.

Good tone production on a string instrument is so closely tied to good intonation, bowing, and a concept of sound that even the best instruments cannot rescue bad playing, but they help. When selecting an instrument for purchase, begin by playing the open strings and a scale to test for a clear and even tone across the entire range. Sometimes one string sound jumps out and another is muffled. School instruments often are clunky, with useless weight in the scroll and too thick a neck. Excess weight does not affect tone directly, but it tires a player, and as the instruments droop and the bow slides onto the fingerboard, the sound diminishes. Do not buy instruments by the pound. Although shiny, new instruments attract younger students, looks do not affect sound. A handmade instrument is also no guarantee of good tone; often adjustments to a factory-made instrument produce a pleasant tone.

Repairmen can adjust instruments through surgery, such as shaving some wood inside to thin a plate, or by moving the sound post and bridge slightly to favor one string over another or to improve projection. The sound post may fit differently as the wood swells or contracts with climate changes. The sound post should contact the back and belly firmly without being too tight. Most school instruments have a thick and unfinished bridge, but a repairman can adjust it so the feet fit the arching of the instrument.

The bridge height and curve should be graduated to fit the fingerboard. When a bridge is too low, the strings will buzz with the least bow pressure and project poorly; when it is too high, young fingers have difficulty depressing the strings. Many professionals keep two bridges for their instruments, using the lower one in the summer and the higher in winter. A repairman may decide to thin the top of the bridge slightly, adjust the depth of the notches for the strings, or move the feet forward or back a little.

Teachers can use a file to sand down the notches if a string slips on the bridge. Sometimes pasting a small piece of parchment in the saddle will correct a notch so deep that the string rests below the top of the bridge; old drum heads are a possible source of material for this. The bridge should not slant forward as this will cause warping and affect intonation. Whether the bridge is centered can be determined by measuring the distance of each foot to the adjacent f-hole.

Strings should be replaced at least annually. A string becomes false when it sounds like a sick cow at the end of a bow stroke and is difficult to play in tune. Check the string condition with long bow strokes on open strings. Perlon core and metal strings last longer than gut-wound ones. They stay in tune better and strengthen the tone slightly, making them popular choices for school orchestras.

Bows should be re-haired at least annually and checked for warping. Professional players re-hair their bows more often, but students may wait until there are only a dozen oily hairs left. Students also tend to rosin bows sparingly because worn hairs without rosin assure a soft sound that escapes notice. Bows and instruments should complement each other. Experiment with combinations of them to find the best match. Instruments become the obsession of some players, collectors, and investors, but fine performers can do greater wonders with poor instruments than the other way around.

Students who have a mental image of the beautiful sound they seek will work to achieve it, and the vibrato and bowing exercises become more tolerable with a goal. It is important for students to hear examples of fine string tone to develop this concept. Recordings and concerts by great artists will change players’ concept of sound. If their concept is small, apologetic, and scratchy, they will find a way to replicate that even on a Strad, Guarneri, or Amati. On the other hand, if the ideal is rich and free, they often can coax that sound out of a beat-up or poorly adjusted factory violin, given proper fundamentals of bowing.