Their is another answer, but in itself it creates a problem ..... Technically the answer is correct, but as the amplifier and the cab handle frequency's lower than normal acceptable volume levels, and the octaves are lower, the Bass is almost always driven at four / six times the power of other instruments.  Somewhat overpowering to all members of the band, as well as the "listeners" resulting in the overall sound becoming "Muddy" due to the overpowering Bass notes.  therefore you need a bass cab that is extremely well made to stop it vibrating itself to destruction and a decent driver to accomplish an acceptable sound at lower levels. Few band's accomplish this which makes a performance difficult for the entire band to be happy with the result.