Before there was rock and roll there was still a need for hearing aids. AT&T developed them in the 1920s, when the loudest musical thing around was Louis Armstrong's trumpet. The 1926 model weighed 11 pounds. By the 1940s hearing aids weighed only a pound apiece and were considered "portable." Today, even President Bill Clinton wears a hearing aid, his badge of honor from 40+ years of rock music.