The contralto voice in opera and classical music has a range which typically lies between the F below middle C (F<sub>3</sub>) to two Fs above middle C (F<sub>5</sub>). In the lower and upper extremes, some contralto voices can sing from the E below middle C (E<sub>3</sub>) to two Bs above middle C (B<sub>5</sub>). The contralto voice has the lowest tessitura of the female voices and is noted for its rich and deep vocal timbre. True operatic contraltos are very rare. The following is a list of contralto singers who have regularly performed unamplified classical or operatic music in concert halls and/or opera houses.