How the structure of the viola has changed over the years
The four strings on a viola are tuned in fifths to the notes c, g, d', and a'. This tuning is exactly one fifth below the violin, expanding the instrument's low range. Of course, while the instrument itself is larger than a violin, violas are not kept to strict size standards even today. It is said that the ideal size when it comes to acoustics is 1.5 times that of a violin, but that would make the instrument far too large to support with the arm and shoulder. Violas therefore must be made slightly smaller than this ideal size. During the Baroque period, two types of violas were produced at the same time: a slightly smaller instrument capable of clean playing in the alto range, and a slightly larger instrument suited for playing in the tenor range. The larger of these was later modified to make it smaller. Compared with the bright sound of violins, violas produce a refined and more somber timbre. This is likely due to the compromise that had to be struck between acoustics and size.
The structure of the viola has changed over the years in a similar fashion to that of the violin. The body of the instrument was reinforced in order to allow it to play louder music more evenly. The neck was attached at a sharper angle and the bridge was made more durable, allowing for the strings to be strung more tightly and dramatically increasing the instrument's volume. Violas were strung with bare gut strings until the 17th century, but in the 18th century the lowest string (C) was replaced with a reinforced gut string wound with metal. In the 19th century the G string was also replaced with reinforced wound string. Modern violas generally use steel strings wound with metal, making them even louder.
