In the early 1980s, Wu Aiguo from the Shanghai Conservatory of Music and Shen Yuqing from the Shanghai National Musical Instrument Factory No. 1 cooperated to jointly reform and develop the vertical double-pipe bau. With the original timbre characteristics and without adding a button, the sound range is extended to nearly two octaves, and it can play two-tone and polyphony, and can be transferred, which significantly improves the expressiveness of Bau's music.

This different-toned double-tube bawu is composed of a blowing head socket, a tube body, a reed and a horn pad. The blowing head sockets are two independent copper blowing pipes, the upper end is a curved mouthpiece, the lower end is provided with a socket for placing the pipe body, and the blowing head is equipped with copper reeds. There are horn pads sandwiched in between. The two pipes are made of bamboo pipes with a relatively thin inner diameter, and the upper end is inserted into the blower socket. One is Bau in G key, with a range of b-e2; There are superimposed sound areas as wide as a major sixth, with as many as five repeating sounds.

When playing, the body of the pipe is placed vertically, the mouth contains a mouthpiece, and the air flow passes through the blowing head to vibrate the reed to press the hole to pronounce. Range b-a2, nearly two octaves. It can play not only single-tone melody, but also full-bodied two- to octave two-tone and two-tone melody, and can play the three keys of D, G, and C of the pentatonic scale. In terms of timbre, the traditional Bau's pure and rich timbre is maintained. Because the reed is placed in the blowing head, the tongue does not touch the reed when playing, so that oral skills can be exerted. During playing, as long as the original melody is converted to another Bau to play, the timbre changes and tonal contrast can be achieved, thus enriching the expressiveness of the music. Wu Aiguo's solo pieces include: "Jin Dalai", "Kailuo" and so on.