There are three differences between a bobble and a stacked note on a hulusi:

1. The speed requirements are different. The speed of vibrato can be fast or slow, depending on the speed of the piece and the duration of the note. Vibrato can be fast and slow, or slow and fast.

2. The use of vibrato is different. In the wave, in addition to the note, other than the note, the other notes are not to use the spit. Vibrato need to use the spit to play the head.

3, the finger requirements are different. Boeing only requires finger movements to be fast and light, finger movements should be consistent. The vibrato practice is the most important part of the finger skills, it is related to the flexibility of the fingers, independence and persistence, as well as the strength of the elasticity and so on. So you must take out enough time to practice for a long time.

Expanded Information:

A wave is a rapid fluctuation of ornamentation between the main note and the neighboring notes, starting from the main note and moving up or down.

Waves are made by adding a short auxiliary note above or below the two main notes between them. There is a smooth wave, a reverse wave, a single wave, and a compound wave.

Waves generally take up the time of the main notes. Wave notes are notated above the main note. There may also be a variation above or below the wave note, which is used to indicate the raising or lowering of a secondary note.

Source:Baidu Encyclopedia - Waves