The flute has a membrane hole for horizontal blowing, and the xiao blows vertically and has no membrane hole, but has a rear sound hole.
Xiao is also known as "di", "chi", "yue" and so on. Some music lyrics are described in this way: ancient musical instruments, made of bamboo, with sound holes like flutes. It was not stated whether it was a horizontal or vertical blow. There are also short recorders, not filmed, and the timbre is between the flute and xiao, which is closer to the flute.
Well, in ancient times, there was little difference between the horizontal blowing instrument without film and the vertical blowing instrument, and the sound was closer to the flute. There are different opinions about the origin of Xiao and Flute. According to the records of "Zhou Li", "Zhou" has been used in the elegant music of the Zhou Dynasty. Synonymous with flute. But the chi is a vertical flute, not a horizontal flute. Originally four finger holes. In the Western Han Dynasty, 1 hole was added to make it become 5 holes. In the Jin Dynasty, there were already 6 finger holes, which are similar to the modern Xiao. With the excavation of archaeologists, two horizontal blows from the Spring and Autumn Period and the Warring States Period were unearthed in Suizhou, Hubei. With 6 holes, the shape is very similar to the bamboo flute, but one end is closed.
During the Wei and Jin Dynasties, it has been used as the main instrument in the band. In the Tang Dynasty, there appeared a flute with 6 holes in the front and a bamboo film on the side, called Qixing Dizi ("Book of Music"). In the Yuan Dynasty, the dragon flute was exactly the same as today's 6-hole bamboo flute.

So far, the concept of flute and xiao has been basically clarified: horizontal blowing is a flute, vertical blowing is a flute. So, which musical instrument was first created and used by people? From the perspective of human body structure, vertical blowing is more in line with the normal state of motion of the human body, while horizontal blowing requires one arm to be sideways, while the other arm requires beyond the front chest to the other side of the body. Therefore, it should be blown vertically in the front and horizontally in the back.
But due to the high volume of horizontal blowing. It spreads far, and after adding the membrane, the tone is crisp, bright, and expressive, and more and more people play the flute gradually. Xiao has a low volume, soft tone, sweet and elegant, suitable for solo and ensemble. The low volume of playing is due to the structure of the flute itself. The blow hole of the flute is very small, and it is inclined inward according to the thickness of the pipe wall, so that when the air is large, the sound will not be played.
The xiao is suitable for playing low and euphemistic tunes, expressing delicate and rich emotions, entrusting the quiet and distant reverie. It is quiet and elegant, with endless aftertastes, and it is rare to meet friends and be intoxicated by it. For our fast-paced modern urban life, it will undoubtedly enable you to appreciate the simplicity of beauty, return to nature, relax your nervous nerves, pursue emotional tranquility, and sublimate your thinking consciousness and enjoy beauty.