Anybody know why they call it a subwoofer?

Question

Is it below the sound of a dog's bark or something?

Answer 1

Lets take it by steps:
1) woof = The characteristically deep, gruff bark of a dog. OR A sound similar to a woof.

2) a woofer = something that makes a "deep sound"

3) a SUBwoofer = makes even lower pitched sounds.

Just a guess...

Answer 2

tweeters are for high pitches
mids are for mid range sounds
woofers are for low range sounds
subwoofers are for extremely low sounds

although, my bass guitar amp has a 15" speaker, not a subwoofer....