1876 Bell and Watson applied for a telephone patent and invented the first practical telephone handset.

1877 Siemens, Germany, put forward the prototype patent of the loudspeaker.

1878 British physicist Rayleigh published "acoustic principles"

1890 A. White invented the shoulder microphone (the embryonic form of the telephone now).

1907 de froest invents triode electron tube.

19 1 1 The lever speaker of the radio appears (as shown in figure 1-6).

19 17。

19 18 phonograph loudspeaker reinforcement equipment in telephone receiver room produced by American West Electric Company.

19 19 A.G.Webster was the first to apply mathematical methods to the design of loudspeaker horns.

1920 Johnson issued a patent for radio speakers.

192 1 Magnavox company produces horn speakers.

1922 E.Gterlach of Siemens invented the belt electroacoustic transducer.

1923 kellev put forward an open baffle, which closed the box at the back.

1924 electromagnetic cone speaker produced by American west electric company (as shown in figure 1-7).

1924a.s. The electric loudspeaker invented by Sykes and Glock.

1924 rice and Kellogg in the United States invented the electric microphone.

1925 Hanna and Slperian in America discussed the design method of loudspeaker.

1925 has a speaker (as shown in figure 1-8).

1926 electric cone loudspeaker has been put into the market by Magnavox company.

Adopt 1927 positive seam ring.

1929 Kyle introduces classic speakers.