Horn speaker consists of vibration system (tweeter) and horn. The vibration system is similar to a paper basin speaker, except that its diaphragm is not a paper basin, but a dome-shaped diaphragm. The vibration of the diaphragm radiates sound waves into the air through the horn (after two reflections). High frequency, loud volume, often used outdoors and outdoors.

When we blow from the small hole in the bottle, the air pressure will increase at the beginning of closing the bottle, which will compress the elastic skin of the balloon. After the skin of the balloon is pushed away by the force generated by the air pressure, there will be a gap between the balloon and the suction pipe, and the air flow will slip out through the suction pipe, which will cause the air pressure to decrease at this time, and the balloon will bounce back to its original position and contact the suction pipe again to be closed. Repeatedly, the skin of the balloon vibrates back and forth repeatedly, thus pushing the air to vibrate and make a sound.

1. The horns used by the ancient army were made of animal horns, so they were called horns. Because of its majestic voice, the horn was used to give orders on the battlefield, such as "whistle for retreat" and was later used as the etiquette for emperors to travel. With the widespread use of horns, the materials used to make horns are changed to bamboo, leather, copper and screws, which are easily available. Its models are also different in length and size to meet different needs.

After the Ming Dynasty, the horns made of bamboo and leather disappeared, and the horns made of copper were widely used. By the end of the Qing Dynasty, when the new army was founded, foreign trumpets prevailed and the horn withdrew from the historical stage.

2. The Horn is one of the French poems Song of Roland, which has two parts: the death of Roland and the death of an ode.