The violin was the first instrument of the orchestra to reach its current state of perfection. In fact, there have been no significant modifications made to the instrument since 1700. There will continue to be small refinements, but the majority of changes to the modern-day violin deal with ornamentation and designs of the scroll of the violin, an essentially nonfunctional part. The violin is constructed with four strings that each have a distinct tone quality. These strings make it possible to play more than four octaves.
The G string is the lowest and thickest string of the violin. It has a deep, dark and gritty texture not found on the other strings. Composers and orchestrators may specifically call for a performer to play an entire passage on this string by marking "sul G" in the score.
Unlike the G string, the D string gives off an air of neutrality. It is the second-lowest string on the violin. The D string is the least characteristic of all the strings and has a uniform sound from the lowest D right above middle C to its highest pitches. It has a mellow tone and is useful for blending in passages with the rest of the orchestra. This string does not stand out and is perfect for pieces that require a subdued sound. Rimsky-Korsakov writes a section for "sul D" in the third movement of his "Scheherazade."
The A string is a much brighter string than the D string. It is the second-highest string and sits between the D and E strings. Most passages are played on the A string, as it is in the middle-upper part of the violin range. Only the lower pitches on the A string will commonly be used since the higher pitches lose much of their power. However, the higher pitches on the A string do suit themselves well to softer passages in solo works.
The E string is an exceptionally powerful and piercing string. It is capable of playing extremely high and has a penetrating nature. The E string is the most brilliant-sounding of all the strings. The sound maintains its affecting brilliance into the uppermost range.