Bass describes tones of low frequency or range from 16-256 Hz (C0 to middle C4). In musical compositions, these are the lowest parts of the harmony. In choral music without instrumental accompaniment, the bass is supplied by adult male bass singers. In an orchestra, the bass lines are played by the double bass and cellos, bassoon or contrabassoon, low brass such as the tuba and bass trombone, and the timpani (kettledrums). In many styles of traditional music such as Bluegrass, folk, and in styles such as Rockabilly and jazz, the bass role is filled by the upright bass. In most rock and pop bands and in jazz fusion groups, the bass role is filled by the electric bass. In some 20th and 21st century pop genres, such as 1980s pop and Electronic Dance Music, the bass role may be filled with a bass synthesizer.
Played in a musical ensemble such an orchestra, such notes are frequently used to provide a counterpoint or counter-melody, in a harmonic context either to outline or juxtapose the progression of the chords, or with percussion to underline the rhythm. In popular music the bass part most often provides harmonic and rhythmic support, usually playing the root or fifth of the chord and stressing the strong beats. "The bass differs from other voices because of the particular role it plays in supporting and defining harmonic motion. It does so at levels ranging from immediate, chord-by-chord events to the larger harmonic organization of a entire work."
Kinds of bass harmony
In classical music, different forms of bass are: basso concertante, or basso recitante; the bass voice of the chorus; the bass which accompanies the softer passages of a composition, as well as those passages which employ the whole power of the ensemble, generally played by the violoncellos in orchestral music; contrabass (“under bass”), is described as that part which is performed by the double basses; violoncellos often play the same line an octave higher, or a different melodic or rhythmic part which is not a bassline when double basses are used; basso ripieno; that bass which joins in the full passages of a composition, and, by its depth of tone and energy of stroke, affords a powerful contrast to the lighter and softer passages or movements.