The main difference between a bass and a tenor saxophone is their size, pitch range, and sound.
Bass saxophones are much larger than tenor saxophones, standing over six feet tall and weighing up to 35 pounds, whereas tenor saxophones typically stand around three feet tall and weigh around six pounds. Due to their size, bass saxophones have a lower pitch range than tenor saxophones and are typically pitched in the key of B-flat, while tenor saxophones are pitched in the key of B-flat or occasionally E-flat.
In terms of sound, bass saxophones have a deep, rich, and powerful tone, while tenor saxophones have a warm and expressive tone that is often used in jazz, rock, and pop music. Due to its larger size and lower pitch range, the bass saxophone is often used as a supporting instrument in classical and jazz ensembles, whereas the tenor saxophone is a popular solo instrument.
Overall, the choice between a bass and a tenor saxophone depends on the player's preference, musical style, and playing requirements.