Loudspeakers
The lowest note on the double bass or four-stringed electric bass is E1, two octaves below middle C (approximately 41 Hz), and on a five-string it is B0 (approximately 31 Hz). The requirement to reproduce low frequencies at high sound pressure levels means that most loudspeakers used for bass guitar amplification are designed around large diameter, heavy-duty drivers, with 10", 12" and 15" being most common. The choice of speaker represents a compromise: while some speakers more effectively reproduce low frequencies, they may have poorer midrange and transient response.
Bassists who want powerful low end may use a subwoofer cabinet designed for a PA system. Subwoofers can only produce frequencies up to about 150 or 200 Hz, so a subwoofer cabinet must be paired with a full range speaker to obtain the full tonal range of an electric bass or upright bass.
Read more about this topic: Bass Instrument Amplification