People have learned to use simple speakers to complete the sound reproduction very early. The function of the early speakers is relatively simple. The sound it reproduces is not realistic at all, and it cannot give the audience an immersive experience. With the advent of electronic recording and playback devices, people's pursuit of perfect sound reproduction has also risen to new heights.
The concept of a dynamic speaker was invented by two Americans, Rice and Kellogg, in 1924, but there are also signs that a British engineer, Paul Voigt, may have applied this concept earlier. Interestingly, although 80 years have passed, the basic speaker technology has not changed much, and the speakers that people use are still based on moving coil technology. The biggest change is the emergence of the stereo concept, which can show the direction and depth of the sound through the two speakers, so that the listener can get a more realistic sound field experience.
The United States Radio Company (RCA) first introduced stereo records into commercial applications in 1957, starting with dual-track tapes as storage media and later using vinyl records for storage. Most record companies gradually abandoned mono in the 1960s and turned to stereo technology. Although the stereo effect is undoubtedly much better than mono, it is not particularly ideal, for example, it cannot provide a stable sound field effect according to the change of the listener's position.