The central variables: Speed, Point of Contact, Pressure
Discussion of these three basics of tone production features in almost every pedagogical text. Thus we find in Spohr comments such as "It is ... necessary to establish how gentle or strong the pressure of the bow on each of the four strings has to be, in proportion to the speed of the bow stroke - and to what extent the hair may be allowed to approach the bridge." Spohr, Violinschule, p.26, quoted in Stowell, p.137.
Bow speed and bow division are among the first things to learn about in controlling musical line and dynamic. Speed the bow up to get louder, or use less bow for a soft détaché. As you progress, bow speed must relate to the other variables. For example, playing softly will often involve faster bow speed, but with less pressure, and a point of contact nearer the fingerboard.
The more advanced player can become engrossed in discussions of pressure and sounding point and can neglect the basics of speed and good bow division. However the daily diet should still include basic exercises for speed and division, such as the Galamian variations for the Kreutzer Studies.
Bow division planning
Choose a piece like "Cantabile" by Paganini, or the first movement of Barber's Violin Concerto, and notate in detail the bow division for the opening page. See Gerle, The Art of Practising the Violin, p.59, for an analysis of the opening of Mendelssohns Violin Concerto.
Point of contact (sounding point)
We vary the point of contact to create a range of tone colours. However, there are fundamental rules for making a clear sound.
Differing point of contact for different strings
Practise Kreutzer "Study No.10" to change points of contact between the thicker G-string and the thinner E-string. Pull the bow closer to the bridge every time you move from the G to the E-string.
Differing point of contact for different positions
The higher we play up a string the closer to the bridge we need to be. Experiment with this change by practicing three-octave arpeggios or Kreutzer "Study No.12". Harmonics are like high-pitched notes in that they also need a point of contact near the bridge.
Five sounding points
It can be helpful to give names to the places where we play between the bridge and fingerboard. Many pedagogues have divided this area into five sounding points, with number five over the fingerboard and number one close to the bridge. Simon Fischers Basics, p.41, has a good diagram of the difference in sounding points between high and low positions.
Pressure (or Weight or Friction)
The bow arm needs to maintain enough friction to enable clear articulation and a resonant sound. This is particularly important when playing in the upper half where the bow is light, or when playing slow bows near the bridge where the resistance is strong. Think of the words friction or resistance to focus on this point.
Teachers can draw attention to this with phrases like: "Your coordination suffers because you lose friction on the string crossing." "Can you increase the resistance between bow hair and string when playing in the upper third?"
The efficient use of pressure can come from the 2nd and 3rd fingers in the middle of the bow hand, or the 1st finger, or pronation. All will use counterpressure from the thumb.
Support the hand and fingers with the whole arm. In turn the whole body supports the bow arm.
Have enough give in the hand and fingers to allow the string to vibrate freely.
Practise applying pressure and release in pulsing. (See Bow Friction 1).
Remember, as we go higher up the E-string and the string gets shorter, we need less pressure from the bow. From a high A onwards it is useful to think of the intensity coming increasingly from the vibrato.
For an even sound the more gradually we add pressure to the down-bow the better, since any surges will cause the bow to jitter.
Above all - listen to your sound.
The concept of weight of the arm can be useful when you want to sink into the string or to release a tight bow hold. It can however be negative if it leads you to collapse the right arm unit. The whole arm should be buoyant and agile, even when playing sustained forte passages.
See Robert Gerles The Art of Bowing Practice, p.45, for a good description of how the weight of the bow arm relates to tone production.
Further points for tone production
Desire is the beginning
It is hard to engage a student to work on tone if they just listen but do not hear. Challenge the ears of students by playing recordings including those of past and present masters such as Elman, Menuhin, Oistrakh, Perlman, Rabin, Szigeti, and Zukerman, to name a few.
When working on our sound we need to remember that the intensity of vibrato needs to match the intensity of the bow. We use the bow differently if we are playing without vibrato and will shy away from a large, romantic sound unless the vibrato supports it.
Generally, do less!
When performing we need to do the right things. However while we are learning the parameters of the correct way of doing it there is a strong tendency to overdo. It is easy to over press or suddenly bring the bow too close to the bridge.
Try to find a neutral position to begin: moderate bow speed, sounding point number three, perhaps using the finger interchange exercise to allow a moderate amount of pressure. (See Bowhold - Advanced - Alternating Fingers).
Tension and release
All our sound comes from a balance of tension and release.
For example, tension can be the use of high friction as in playing near the bridge or the impact of three-note chords landing from the air. This needs to be released in some way. Playing near the bridge needs a slow bow; three-note chords need fast bow speed on landing to dissipate the impact.
Playing fast détaché can be tiring, especially for sustained periods such as in the "Preludio" from Partita No.3 by J.S.Bach, where you need to maintain the bow friction over constant string crossing. This tension can be released with the give in the joints of the fingers and thumb.
Good quality strings
Strings that are old, or false, or caked with rosin will not ring.
The stick is not the hair
Flexibility in bowhair and bowstick is different at different points in the bow. Both give in the middle but diverge at the point and the frog. You can notice this in these ways:
Watch the bow stick movement in the middle of the bow when playing sautillé.
Watch the stiffness of the stick at the point to monitor your articulation in the martelé.
Bow hair inclination and tightness of bow hair
We are constantly changing the inclination of the bow hair to make different tone colours or articulations. However there are some general principles to observe.
We commonly use the flat of the hair for:
Playing in the middle or upper half (especially when playing loudly).
We commonly use the side of the hair for:
Playing in the lower half (especially when landing from the air).
Softer dynamics (especially towards the fingerboard). If you play with low hair tension you will need to use flat hair more often (especially when playing loud passages). If you play with high hair tension you will use the side of the hair more often.
Know your bow
The amount of inclination also depends on the style of bow and how much give there is in the middle. If the bow is weak in the middle then flat hair is needed when playing loudly to stop the wood scratching the string.
Push the violin up towards the bow
Maintain a stable violin position when playing loudly. If we let the violin scroll dip down we are creating more work for the right hand. Commonly this happens when the bow comes from the air. Practise pushing the violin up towards the bow in such passages. Experiment playing loud passages without a shoulder rest and varying the sound by pushing the violin towards the bow and back again.
Horizontal pressure - The living string
When trying to project we can easily crush our sound. To work on releasing the sound feel the down-bow pulling the left edge and the up-bow pushing the right edge of the string.
Monitor the bow hand
Tight, unbalanced bowholds create problems in all bow strokes and need our attention when working on sound. As a matter of course when practising, experiment with taking fingers off the bow. Try the Adagio from Rodes "Caprice No.9" without the 1st or 2nd or 3rd fingers on the bow. (See Alternating Fingers).
You can even experiment playing without the thumb when playing lower than the balance point of the bow.
Maintain the arch in the bow hand even in the upper third of the bow. Do not let the base joints of the hand collapse and do not push the wrist down.
Sensitivity of the fingers is important when playing all tone colors. Feel that the fingers could activate a collé stroke at any time. Practise stopping halfway through the bow and restart the stroke with a collé-like click.
The 2nd and 3rd fingers are important and are often overlooked. When projecting a strong sound feel them working the bow stick to keep the bowhair in the string.
The first pad of the 3rd finger is particularly important in maintaining resonance throughout a stroke. Practise in the middle and upper half with the 2nd and 4th fingers lifted off the bow. Release and re-contact at the frog of the bow with this pad of the 3rd finger and hear the difference in the sound.
Question the use of the 1st finger, which is strong and can be easily overused. When working on sound, also practise without the first finger on the bow in order to engage the rest of the bow hand. This is useful when practising a variety of strokes such as sautillé, spiccato and three-note chords. (See Lifting the Bow at Heel, for example).
We often hear that we should loosen the right thumb. Another way to express this is to equalize the effort between thumb and fingers. An open bow hand relies on:
An un-collapsed thumb
Released joints in the thumb, particularly the second and third joints. Remember that the thumb has three joints, like the fingers. The third (base) joint is near the wrist.
A note will only ring when it is in tune.
Check your intonation as you practise tone production.
Listen for overtones.
Watch to see the string vibrate, work towards the maximum width of vibration.
Touch another players scroll between thumb and fingers as they experiment with differing bowstrokes. Feel the vibration in the scroll that comes from the open, resonant sound.
The more challenging a task, the more support we need from our body. When working to increase friction and project a strong sound there is a temptation to collapse downwards.
As the violin bow exerts high friction into the string try to:
Feel the counterpressure all the way from your feet. (Try playing in socks, or on a wobble board to activate greater feedback from your feet).
Make a soft bow hand for a big sound.
Imagining a tone colour can lead you to play with more convincing sound. There are many examples of such images in the books of Phyllis Young.
Tone Production - Bow Friction 1
Bowhold - Advanced - Alternating Fingers
Bouncing Bowings - Lifting the Bow at Heel
Resources - Bibliography
Resources - Repertoire