Development history of sound box

Since the dawn of human dream, we always try hope that one day I can leave the sounds of nature, hidden in the bosom, even will they repeat playback. The hope to try to finally got his wish is human in electric and acoustic exploration gradually worked, gradual growth process.
Electrostatic speaker:
In order to better tell the story of human acoustic history story, us from first to start with the human voice to convey to the distance of "telephone". Graham Bell Alexander proposed a history of the most important patent on February 14, 1876, a hundred years ago. ". The invention makes the human voice could then spread to shout farther than, humans also henceforth know the conversion relation between acoustic and electric, and since bored.
In order to better playback records recorded by the sound, in 1910, G. Brown S. will drive and the vibration membrane separation, the invention of the'armature'armature headphones.
Balanced armature earphone:
In 1910, Baldwin invented the armature''balanced balance armature headphones. Armature earphone is in the middle of a U-shaped magnet of the erection of a movable iron piece (armature), when the current flowing through the coil armature will by magnetization with the magnets to generate attraction and repulsion phenomenon, and simultaneously drives the diaphragm movement. This design is cheap, although the effect is not good, but at the time of the invention of the invention, the technology used in the phone tube and small headphones.
By the mid 30's, according to the principle of the condenser microphone, electrostatic speaker available. In the early 50 "s, V. Bocciarelli C. proposed the constant charge rule of charge''constant. Walker P. developed the same theory independently in the same time and applied it to the famous Quad electrostatic speaker design..