The double-pipe Bau is based on the traditional Bau, and through the combination of two Bau, the Bau's range and performance are expanded on the basis of not destroying the natural and most beautiful sound of the Bau.

The shape of the double-pipe Bau looks like two Bau bundles, and there are two supervisors, so it is called the double-pipe Bau in the image. From the point of view of the sound range and playing method of a single supervisor, it is also the same as the traditional Bau. The innovation lies in the different fingering used on the two supervisors, which expands the Bau's vocal range by 3 tones.

According to the different tuning of the Ba'u's tone, the sound range of the double-pipe Ba'u can be from bass 5 to treble 2, bass 2 to treble 6, bass 1 to treble 5, which results in three common fingerings. 80% of the songs can be played with the double-pipe Bawu, and several fingerings mentioned in the traditional cucurbit flute textbook can also be fully used on the Bawu. Therefore, in addition to expanding the playing range, the double-pipe Bau also deepens Bau's playing skills.