The main difference between a bass and a baritone saxophone is their range and size.
A bass saxophone is the largest and lowest member of the saxophone family, and it is pitched in the key of B-flat, one octave below the tenor saxophone. It has a deep, rich, and resonant sound that is often used in classical music, jazz, and other genres.
A baritone saxophone, on the other hand, is smaller than a bass saxophone but still larger than most other saxophones. It is pitched in the key of E-flat, a perfect fourth below the tenor saxophone. The baritone saxophone has a lower range than the tenor saxophone and a higher range than the bass saxophone. It has a warm, mellow tone and is often used in big band and jazz ensembles.
Overall, while both bass and baritone saxophones are larger and lower-pitched than other members of the saxophone family, the bass saxophone is the largest and lowest-pitched, while the baritone saxophone is smaller and has a slightly higher range.