brass instruments

• To effectively change pitch on a valved brass instrument , two things come into play : the pressing of valves to effectively change the length of the tubing , and the player ' s lip aperture or " embouchure " setting , which determines the frequency of the pulsed air or vibrations into the instrument
  要在按键乐器上改变音高，有两个方法能够办到：一、压下按键改变管子的长度，二、演奏者所吹出的气流改变嘴唇的振动频率。