Violin completely losing tension. A violin in which the tuning pegs are slipping needs to be repaired by a luthier or violin repairperson. Peg dope or peg compound, used regularly, can delay the onset of such wear, while allowing the pegs to turn smoothly. The tuning G–D–A–E is used for most violin music, both in Classical music, jazz and folk music. Other tunings are occasionally employed; the G string, for example, can be tuned up to A. The use of nonstandard tunings in classical music is known as "scordatura"; in some folk styles, it is called "cross tuning". One famous example
Concert pitch D-flat), and are often tuned to match B brass instruments when the two are required to play together. The Stuttgart Conference of 1834 recommended C264 (A440) as the standard pitch based on Scheibler's studies with his Tonometer. For this reason A440 has been referred to as Stuttgart pitch or Scheibler pitch. In 1939, an international conference recommended that the A above middle C be tuned to 440 Hz, now known as "concert pitch". As a technical standard this was taken up by the International Organization for Standardization in 1955 and reaffirmed by them in 1975 as ISO 16. The difference