Electric speakers have become the mainstream in the market with simple structure
In 1898, Sir Oliver Lodge of the United Kingdom further invented the cone horn according to the principle of the telephone megaphone. It is very similar to the modern horn we are familiar with. This invention determines the structure of 99% of the modern dynamic speaker now called "Roaring". phone". However, this invention could not be used, because it was not until 1906 that Lee De Forest invented the three-pole vacuum tube, and the available expansion machine was several years later, so the cone speaker was only popularized in the 1930s.
It took another 25 years, and in the 1920s, radio broadcasts appeared. C. W. Rice and E. W. Kellogg published the epoch-making paper "New Non-Cartridge Units", detailing direct-radiation loudspeakers, and the Radiola 104 loudspeakers designed with this theory are popular in the United States. In the past few decades, the basic principles of electric speakers have not changed, only the design details and parts have been improved. The dynamic range of the frequency response range has made considerable progress in older products. The electric speaker has a simple structure, excellent sound quality, low cost, and large dynamic has become the mainstream in the current market.