A bass is a type of classical male singing voice and has the lowest vocal range of all voice types. According to The New Grove Dictionary of Opera, a bass is typically classified as having a vocal range extending from around the second E below middle C to the E above middle C (i.e., E2–E4). Its tessitura, or comfortable range, is normally defined by the outermost lines of the bass clef. Categories of bass voices vary according to national style and classification system. Italians favour subdividing basses into the basso cantante (singing bass), basso buffo ("funny" bass), or the dramatic basso profondo (low bass). The American system identifies the bass-baritone, comic bass, lyric bass, and dramatic bass. The German Fach system offers further distinctions: Spielbass (Bassbuffo), Schwerer Spielbass (Schwerer Bassbuffo), Charakterbass (Bassbariton), and Seriöser Bass. These classification systems can overlap. Rare is the performer who embodies a single Fach without also touching repertoire from another category. History Cultural influence and individual variation create a wide variation in range and quality of bass singers. Parts for basses have included notes as low as the B-flat two octaves and a tone below middle C (B1), for example in Gustav Mahler's Symphony No. 2 and the Rachmaninov's All-Night Vigil, A below that in Frederik Magle's symphonic suite Cantabile, G below that (e.g. Measure 76 of Ne otverzhi mene by Pavel Chesnokov) or F below those in Kheruvimskaya pesn (Song of Cherubim) by Krzysztof Penderecki. Many basso profondos have trouble reaching those notes, and the use of them in works by Slavic composers has led to the colloquial term "Russian bass" for an exceptionally deep-ranged basso profondo who can easily sing these notes. Some traditional Russian religious music calls for A2 (110 Hz) drone singing, which is doubled by A1 (55 Hz) in the rare occasion that a choir includes exceptionally gifted singers who can produce this very low human voice pitch. Many British composers such as Benjamin Britten have written parts for bass (such as the first movement of his choral work Rejoice in the Lamb) that center far higher than the bass tessitura as implied by the clef. The Harvard Dictionary of Music defines the range as being from the E below low C to middle C (i.e. E2–C4). Vocal range Bass has the lowest vocal range of all voice types, with the lowest tessitura. The low extreme for basses is generally