Cello inexpensive wood that has been blackened or "ebonized" to look like ebony, which is much harder and more expensive. Ebonised parts such as tuning pegs may crack or split, and the black surface of the fingerboard will eventually wear down to reveal the lighter wood underneath. Historically, cello strings had cores made out of catgut, which, despite its name is made from sheep or goat intestines which are dried out. Most modern strings used in the 2010s are wound with metallic materials like aluminum, titanium and chromium. Cellists may mix different types of strings on their instruments. The pitches of
Experimental musical instrument of the usual two (counting the nut as a bridge). By adding a third bridge, one can create a number of unusual sounds reminiscent of chimes, bells or harps A 'third bridge instrument' can be a "prepared guitar" modified with an object – for instance, a screwdriver – placed under the strings to act as a makeshift bridge, or it can be a custom made instrument. One of the first guitarists who began building instruments with an extra bridge was Fred Frith. Guitarist and composer Glenn Branca has created similar instruments which he calls harmonic guitars or mallet guitars. Since