Making of a Cello
The cello is much larger than a violin or a viola and smaller than a bass. Like the other members of the string orchestra, the cello has four strings, normally tuned to the pitches (from low to high) C-G-D-A (more specifically, C2-G2-D3-A3 in scientific pitch notation), like the viola but one octave lower (see #Tuning and range). It is played in an upright position between the legs of the seated musician, resting on a metal spike called the endpin. The player draws the bow horizontally across the strings. The cello is a complex instrument consisting of many different parts. Although the majority of it is composed of wood, some parts are made of steel, composite material, rubber, and metal. Today, the strings are most often metal but can be made of nylon or other material, and like the hair of the bow (see below) must periodically be replaced.
The main frame of the cello is made from wood. Cellos are normally constructed with a spruce top. The back, sides, and neck are usually made of maple. Other wood are sometimes used for the back and/or sides, usually poplar or pine. The top and back are traditionally hand carved. Less expensive cellos frequently have a top and back made of a laminate. The sides are made by steaming the wood and bending it around forms, or carved from solid maple. The cello body has a wide top, narrow middle, and wide bottom, the bridge and f-holes in the middle. Also, it should be noted that some modern cellos are constructed from carbon fibre.
Upper neck and pegbox:
Above the main frame is the carved neck, which leads to a pegbox and then a scroll. The scroll is a traditional part of the cello and features in all instruments of the stringed family (except the harp). The three are normally carved out of a single piece of wood. The pegbox consists of four tuning pegs, each which tunes its respective string by either tightening or loosening the string. Ebony is usually used for the tuning pegs, fingerboard, nut (piece above the fingerboard which the strings rest on), and tailpiece, but other dark woods, such as boxwood or rosewood, can be used.
Tailpiece and endpin:
The tailpiece and endpin are designed to support the cello when the cello is being played. The endpin, usually metal, is retractable and is placed at a comfortable distance. The side of the endpin touching the floor is usually a spiked tip that can be capped with rubber; both serve to grip the floor and prevent the cello from moving or slipping.
Bridge and f-holes:
The bridge elevates the strings above the fingerboard. The bridge is not glued on; tension from the strings maintains it in place. The f-holes (named for their shape) are located on either side of the bridge, and serve to allow the instrument to properly sound (produce sound). Additionally, f-holes are as access points to the interior of the body in case of repair, maintenance or for the fitting of a sound post or other device. One example of such a device is called a snake, which maintains proper humidity within the instrument.
Internally, the cello has two important features: a bass bar, which is glued to the underside of the bottom of the instrument, and a round wooden sound post (also called a sound peg), which is sandwiched between the top and bottom. The bass bar serves to support the backbone of the cello, and contributes to the cello’s rigidity. The sound post, meanwhile, is responsible for conducting and absorbing sound. Like the bridge, the sound post is not glued, but is kept in place by the tensions of the bridge and strings.
Cellos are glued together using hide glue, which is strong yet also reversible, allowing for repair and restoration of the instrument should it need to be taken apart.
Traditionally, bows are made from Pernambuco (high quality) or Brasil (lower quality) wood. Both woods come from the same species of tree (Caesalpina sappna L, or sappon wood, native in Asia), but Pernambuco is the heartwood of the tree and is much darker (Brasil wood is stained/painted dark to compensate). Pernambuco is a heavy, resinous wood with great elasticity and high sound velocity which makes it an ideal wood for instrument bows. The hair is horsehair, though synthetic hair has become available nowadays. In addition, the bow can now also be made of fiberglass or carbon fibre (or wood with a carbon fibre core), serving as alternatives to the traditional wooden bow. The hair is coated with rosin (normally every time the instrument is played) to improve the grip on the strings. Bows need to be re-haired periodically as the hair loses its grip over time. The hair is kept under tension while playing by a screw which pulls the frog (the part of the bow one holds) back. Leaving the bow tightened for long periods of time can damage it, by warping the stick.