 Eight-foot pitch may be contrasted with four-foot pitch (4'; one octave above the standard), two-foot pitch (2'; two octaves above the standard), and sixteen-foot pitch (16'; one octave below the standard).The latter three pitches are often sounded (by extra pipes or strings) along with an eight-foot pitch pipe or string, as a way of enriching the tonal quality.The numbers just mentioned largely exhaust the possibilities for harpsichords, but in organs a far greater variety is possible; see Organ stop.