Cello

Overview

A cello is a large bowed string instrument played seated, resting on the floor on a spike, with a tonal range that covers the cello-and-bass register of an orchestra. Drawing a bow across a string sets it vibrating, but a bare string moves almost no air. The instrument's job is to take that small vibration and turn it into sound, which it does by feeding the string's energy into a hollow wooden box tuned to radiate it. Every part of the cello exists either to hold the strings under tension or to carry their vibration into that box.

The resonating box is the Body, built from a carved spruce Spruce Top Plate and a maple Maple Back Plate joined by bent Maple Ribs. The Neck Assembly carries the Ebony Fingerboard and the pegbox. Four Cello Strings run from the Tuning Pegs over the Bridge to the Tailpiece Assembly, and the whole instrument stands on the Endpin Assembly.

How it works

The strings are stretched between the Tuning Pegs in the pegbox and the Tailpiece Assembly at the bottom, passing over the Bridge which holds them clear of the body. A player sets coarse pitch by turning the friction pegs and makes fine adjustments with the tailpiece fine tuners; notes are then chosen by pressing a string against the unfretted ebony Ebony Fingerboard, shortening its vibrating length. Because there are no frets, exact pitch depends entirely on finger placement.

When the bow is drawn across a string, its rosined hair grips and releases the string hundreds of times a second, sustaining the vibration. That motion passes into the Bridge, whose feet rock the spruce top. Two parts inside the body shape what happens next: the Bass Bar glued under the top's bass foot spreads and stiffens the plate so low notes radiate evenly, and the Sound Post, a spruce dowel wedged between top and back just under the treble foot, couples the two plates so they move together and pump air through the f-holes. The Body thus acts as a tuned loudspeaker for the strings. The Endpin Assembly anchors the cello at a fixed playing height, transferring almost none of the sound to the floor so the energy stays in the box.