The belly (also referred to as the front plate, table or top) is the soundboard. It is made of spruce with ideal acoustical qualities, also known as resonance wood. Usually, wood with very regular and narrow, vertical annual rings and a uniform grain orientation is selected. Yet irregularities do not necessarily compromise tonal quality, as some Stradivari violins demonstrate. First, the belly halves are joined with glue, then the arching is carved. The interior is carved with a gouge and various planes to give the thickness needed for optimum tonal quality. After the f-holes have been cut, the belly is glued to the rib structure.