The viola is a bowed string
instrument. It is slightly larger than a violin in size and has a deeper sound.
Since the 18th century it has been the middle voice of the violin family,
between the violin (which is tuned a perfect fifth above it) and the cello
(which is tuned an octave below it)
.
The viola is similar in material and
construction to the violin. A full-size viola's body is between 1 inch (25mm)
and 4 inches (100mm) longer than the body of a full-size violin (i.e., between
15 and 18 inches (38and46cm)), with an average length of 16 inches (41cm). Small
violas for children typically start at 12 inches (30cm), which is equivalent to
a half-size violin. For a child who needs a smaller size, a fractional-sized
violin is often strung with the strings of a viola.
Unlike the violin, the
viola does not have a standard full size. The body of a viola would need to
measure about 20 inches (51cm) long to match the acoustics of a violin, making
it impractical to play in the same manner as the violin.
For
centuries, viola makers have experimented with the size and shape of the viola,
often adjusting the proportions or shape to make a lighter instrument with
shorter string lengths, but which still has a large enough sound box to create
an unmistakable "viola sound".