upwards, and notes on the double bass below the range of the bass voice, descending from
(written sound)
lose in expression and warmth of tone. Open strings are clearer and more powerful but less expressive than stopped strings.
Comparing the range of each stringed instrument with that of the human voice, we may assign: to the violin, the soprano and contralto voice plus a much higher range; to the viola, the contralto and tenor voice plus a much higher register; to the 'cello, the tenor and bass voices plus a higher register; to the double bass, the bass voice plus a lower range.
The use of harmonics, the mute, and some special devices in bowing produce great difference in the resonance and tone quality of all these instruments.
Harmonics, frequently used today, alter the timbre of a stringed instrument to a very appreciable extent. Cold and transparent in soft passages, cold and brilliant in loud ones, and offering but little chance for expression, they form no fundamental part of orchestral writing, and are used simply for ornament. Owing to their lack of resonant power they should be used sparingly, and, when employed, should never be overpowered by other instruments. As a rule harmonics are employed on sustained notes, tremolando, or here and there for brilliant effects; they are rarely used in extremely simple melodies. Owing to a certain tonal affinity with the flute they may be said to form a kind of link between string and wood-wind instruments.
Another radical change is effected by the use of mutes. When muted, the clear, singing tone of the strings becomes dull in soft passages, turns to a slight hiss or whistle in loud ones, and the volume of tone is always greatly reduced.
The position of the bow on the string will affect the resonance of an instrument. Playing with the bow close to the bridge (sul ponticello), chiefly used tremolando, produces a metallic sound; playing on the finger-board (sul tasto, flautando) creates a dull, veiled effect.