Before AT&T invented the condenser microphone, this was how music had to be recorded. Songs were simply played or sung into a large horn where a diaphragm vibrated a metal needle that cut grooves into a wax disk. Obviously, the technology needed an upgrade. That upgrade was the microphone, an outgrowth of the telephone mouthpiece (as headphones were an outgrowth of the telephone earpiece).

  Microphones immediately became indispensible to recording music. With the arrival of rock, they became indispensible to vocalists as well. If you want to imagine how a rock singer would sound without microphones, amplifiers and loudspeakers, go to an opera. And be real, real quiet.