Korean Demilitarized Zone loudspeakers

[5] During the war, the United States, allied with South Korea, used loudspeakers to broadcast propaganda to the North Koreans as a form of psychological warfare.

In September 1950, the U.S.' Tactical Information Detachment (stationed at Fort Riley in Kansas) deployed to Korea as the 1st Loudspeaker and Leaflet Company, supporting to American units across the frontline.

The border between them became the Demilitarized Zone (DMZ), a series of fortifications under continuous defense by both countries, and occupied by both soldiers at the Joint Security Area.

[5] North Korean loudspeakers broadcast sirens, drum noises, and sounds described as "high-pitched and resembling scraping metal".

[10] South Korean politician Tae Yong-Ho has said: "History has proven that loudspeaker broadcasting to North Korea is the quickest and most effective way to peacefully manage the situation along the border and deter war".

[11] In 2016, South Korea purchased 40 to 60 speaker systems for the purpose of having sound reach the North Korean city of Kaesong, 10 kilometers away.

Later that year, however, audits revealed that the speakers were actually too quiet to always reach Kaesong, only going as far as 5 to 7 kilometers north; the three tests done of the new systems in 2016 were conducted at night and in the morning, when sound travels farther than in the day.

[13] The South again stopped using loudspeakers on 27 April 2018, during negotiations with North Korea over the reduction of "hostile tactics" along the DMZ.

[19] Following a national security meeting over the balloons, South Korea withdrew from the 2018 agreement limiting DMZ activities, and on 9 June, resumed the use of loudspeakers at one location.

South Korean defense minister Shin Won-sik said his country was prepared for military retaliation by North Korea.