The bass saxophone is the third lowest member of the saxophone family—larger and lower than the more common baritone saxophone. [...] It is a transposing instrument pitched in B♭, an octave below the tenor saxophone and a perfect fourth below the baritone saxophone. A bass saxophone in C, intended for orchestral use, was included in Adolphe Sax's patent, but few known examples were built. The bass saxophone is not a commonly used instrument, but it is heard on some 1920s jazz recordings, in free jazz, in saxophone choirs and sextets, and occasionally in concert bands and rock music.

Music for bass saxophone is written in treble clef, just as for the other saxophones, with the pitches sounding two octaves and a major second lower than written. As with most other members of the saxophone family, the lowest written note is the B♭ below the staff—in the bass's case, sounding as a concert A♭1. Wikipedia, 13.01.2026