Ray Kellog invents electric moving coil loudspeaker

In 1924, Ray Kellogg, working for General Electric and Western Electric, invented the electric moving coil loudspeaker. This innovative device, also known as a dynamic loudspeaker, utilized an electromagnet (voice coil) positioned within a magnetic field to convert electrical signals into sound. When an audio signal passed through the voice coil, it created a magnetic field that interacted with the fixed magnetic field, causing the coil and attached diaphragm to move and produce sound waves. Kellogg’s invention significantly improved sound reproduction quality and became the foundation for modern loudspeakers used in various audio devices, including radios, amplifiers, and public address systems. This breakthrough greatly enhanced audio communication and entertainment.