Without this invention, our homes wouldn't be filled with our favourite tunes. Used in 1880, horns were the earliest form of noise amplification, but they wouldn't be appropriate for home use.
Alexander Graham Bell patented his first electric loudspeaker capable of reproducing intelligible speech in 1876 as part of his telephone. But, the modern speaker that we know today required an understanding of electricity, radio, sound waves, mechanics, chemistry and physics and, as such, wasn't invented until the 1920s by Americans Edward W. Kellogg and Chester W. Rice.