What is the lowest member of the commonly used saxophone family?

The baritone saxophone is the lowest member of the commonly used soprano, alto, tenor, and baritone saxophone family.

It is a large, single-reed woodwind instrument with a curved neck and a prominent looping section of tubing. Although saxophones are usually made of brass, they are classified as woodwinds because the reed controls the vibrating air stream.

The baritone saxophone is usually pitched in E-flat. In concert bands and jazz ensembles, it often supplies a deep bass or rhythmic foundation, while also being capable of powerful melodic lines. Its size requires more breath and physical support than the smaller saxophones.

The bass saxophone is lower than the baritone, but it is uncommon in standard modern saxophone sections. That distinction makes baritone saxophone the accepted answer when a question refers to the commonly used family rather than every historical or specialist saxophone.