In 1861, John Philip rice installed an electronic loudspeaker on his telephone; It can reproduce clear tones, but it can also reproduce deep voices after several modifications. Alexander Graham Bell applied for the patent of his first electronic
loudspeakers (capable of reproducing understandable speech) in 1876 as part of his telephone, and then obtained an improved version of Ernst Siemens in 1877. It is reported that Nicholas Tesla manufactured a similar device in 1881, but he did not obtain a patent. During this period, Thomas Edison obtained a British patent and invented a system using compressed air as the amplification mechanism of the early cylindrical phonograph, but he finally chose the familiar metal horn driven by the film attached to the stylus. In 1898, Horace short applied for a design patent for a loudspeaker driven by compressed air; He then sold these rights to Charles Parsons, who obtained several British patents before 1910. Several companies, including Victor Talking Machine and path é, have produced recorders using compressed air speakers. However, these designs are significantly limited by their poor sound quality and inability to reproduce sound at low volume. Variants of this system have been used in public address applications, and more recently, other variants have been used to test the resistance of space equipment to the very high sound and vibration levels produced by launching rockets.
The modern design of dynamic drives was established by Oliver lodge in 1898. The first practical application of a dynamic loudspeaker was established by Danish engineers Peter l.jensen and Edwin Pridham in Napa, California. Jason was denied a patent. Because they failed to successfully sell their products to telephone companies, in 1915, they changed their strategy to public broadcasting and named their products MAGNAVOX. In the years after the invention of the loudspeaker, Jensen was part owner of MAGNAVOX.
The dynamic principle commonly used in direct radiators was patented by Chester W. Rice and Edward W. Kellogg in 1924. The key difference between the previous attempts and the patents of rice and Kellogg lies in the adjustment of mechanical parameters so that the basic resonance of the motion system is lower than the frequency at which the radiation impedance of the cone becomes uniform.
Around the same time, Walter h. Schottky and Dr. Elvin grader invented the first strip loudspeaker.
The first speakers used electromagnets because large and powerful permanent magnets were usually not available at a reasonable price. The coil of the electromagnet is called the magnetic field coil, which is energized by the current connection to the second pair of drivers. This winding usually has a dual function and also acts as a choke to filter the power supply of the amplifier connected to the loudspeaker. The AC ripple in the current is attenuated by the action of the choke. However, the AC line frequency often modulates the audio signal entering the voice coil and increases the audible buzz.