Appendix A.2

The aim of this document is to explain and demonstrate some aspects of violin technique that I have found to be important or relevant in collaborative work with composers and also when teaching. I have aimed to keep the verbal explanation concise and to illustrate the techniques using the video examples. The particular choice of techniques presented here is related to the portfolio of pieces explored in my PhD research.
The videos show two angles—one looking directly along the violin from the angle I see it as I play, and the other from the side. The videos can be enlarged to a full screen view using the button in the lower-right corner.

bow action parameters

The following four parameters could also be described as the four factors with which the volume of a note is controlled. They also affect the timbre of a note, and will ordinarily be used in different combinations for varied tone production.

Taking, as a starting point, an open D-string at an approximate mezzo-piano dynamic, half-way between the bridge and the fingerboard, 50% hair contact with the string and an even pressure, the following should demonstrate how each of these parameters affects the sound.

The speed at which the bow is drawn across the string is directly proportional to the volume. Rather than referring to the speed of the bow, people will often talk about using 'more' or 'less' bow, as using a longer section of the bow without adjusting the tempo implies moving it faster.

An increase in pressure of the bow on the string will also increase the volume. This pressure is a combination of the weight of the right-arm and the bow, and additional force from the performer exerted from the upper body and arm and transmitted mostly through the index finger on the stick.

As can be heard in the example, the increase of pressure on its own, without increasing the speed as well, can result in some distortion of the sound.

The lateral position of the bow on the string is important for the projection of the sound and also for timbral variation. Up to a point, the closer to the bridge the bow is on the string, the louder the sound produced. Past this, the timbre of the sound begins to distort with the crackling and high partials associated with a 'sul ponticello' sound, and will lose its power of projection.

Moving the bow further away from the bridge, the projection of the sound is decreased and the timbre becomes softer and fuzzier, a sound associated with a 'sul tasto' indication. Further still, at the harmonic node, half way between the bridge and the stop (nut or finger), there is a particular flute-like timbre that can be achieved.

The amount of hair in contact with the string can be used to control the volume. Tilting the bow so the wood is further away from the bridge will decrease the number of hairs touching the string, and therefore reduce the volume. N.B. The tilt of the bow can also be used to control the natural spring of the bow, which is at its most bouncy when the hair is flat on the string.

contributing physical parameters

Physical attributes of the instrument have an influence on the parameters outlined above and require certain adjustments to basic technique.

The distance from the bridge of the point of contact between bow and string must be adjusted according to the thickness of the string. The example shows the E-string being played, followed by the G-string at the same lateral point. The sound on the E-string is pure, but the same place on the lower string gives a 'sul pont.' sound.

The string length affects this parameter similarly. The shorter the string, the closer to the bridge the timbral spectrum will be. The example shows the lateral movement of the bow towards the bridge for the high stopped note (the string has been shortened by stopping it with the finger). Returning to the open string without moving the bow back to its starting point, the timbre of the note has taken on a ponticello sound.

The part of the bow in which a note is played has an effect on the natural amount of pressure exerted. The bow is heavier at the heel than at the tip, and the weight of the player's arm contributes to this difference. By deliberately using more pressure, this can be countered but, allowing the natural difference in weight distribution to affect the sound, there will be a diminuendo towards the tip of the bow, and a crescendo towards the heel.

The first demonstration is with a modern Tourte-style bow. The second is with a baroque bow (see Appendix A.3 for images), with which this same effect is more extreme due to the design.

combination and adjustment

Every sound produced by the instrument is a product of a unique combination of factors, some of which are described above.

The control of volume and timbre is achieved with a combined choice of the four key action parameters, and continually adjusted as the physical parameters change.

Harmonics depend on the adjustment of the lateral bow position for clarity. As demonstrated, the harmonic played sul tasto does not sound with a clear pitch and does not resonate. The higher the pitches, the closer to the bridge the bow must move for the harmonics to sound.

Subharmonics involve pitch alteration as a particular combination of lateral bow position, pressure, and speed. This enables notes to be played that are lower than the sounding pitch of the open string. This can often be done in error as a result of playing with too much pressure, too far away from the bridge. It can also be used deliberately to create a series of tones that sound below the normal pitch of the string, as seen in the composition of Mari Kimura and George Crumb in his string quartet Black Angels

It is necessary to make an axial adjustment to account for left-hand movement, which is demonstrated here with a glissando from low to high, while simultaneously sustaining an open G-string. The stopped string is lowered by the pressure from the left-hand and the bow angle must be adjusted for the top note to be sustained.

additional techniques

While the focus of this document is on bow technique, it is worth mentioning that the timbre of a pizzicato note is affected by the lateral position on the string in the same way as an arco note. Demonstrated here is the same pitch played 'sul pont.', 'normal', which is actually over the end of the finger board, at the harmonic node, where a true flautando sound can be found with the bow, and a left-hand pizzicato.

Bowing behind the left-hand (also featured in Crumb's Black Angels) has a particularly weak timbre, and the peculiarity that the left-hand pitch positions are reversed.

With a specific combination of left-hand behaviour and lateral bow position, three and four note chords can be sustained. In normal circumstances, the curvature of the bridge allows only one or two notes to be played at the same time. The example shows a stopped 6th sliding up the D and A-strings. The bow can be seen to move closer to bridge to accommodate LH position change, then to move laterally to play all four strings, and then the outer strings only.

Percussive techniques particularly bring out a bitonal quality in the string. The example shows col legno battuto and tratto with the string dampened and with the string open. With the string dampened, the pitch of the contact point only can be heard. When the string is open or stopped, the pitches of the open or stopped note, and of the contact point are audible. Lachenmann's Toccatina makes use of this effect with the screw of the bow.