quality:correction, linguistic:translation
Strings

Historically, cello strings had cores made out of catgut, which, despite its name, is made from sheep or goat intestines. 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 the open strings are C, G, D, and A (black note heads in the playing range figure above), unless alternative tuning (scordatura) is specified by the composer. Some composers (e.g. Ottorino Respighi in the final movement of ‘’ The Pines of Rome ’’) ask that the low C be tuned down to a B-flat so that the performer can play a different low note on the lowest open string.