Woofer
A woofer or bass speaker is a technical term for a loudspeaker driver designed to produce low frequency sounds, typically from 50 up to 200 Hz. The name is from the onomatopoeic English word for a dog's deep bark, "woof" (in contrast to a tweeter, the name used for loudspeakers designed to reproduce high-frequency sounds, deriving from the shrill calls of birds, "tweets").