The significance and the advantage of a minimum-pressure embouchure cannot be stressed too often. Most players can develop the ability to learn it. Often however they lack the patience, the willingness or even the insight to persist in imposing on the lips a maximum of discipline and flexibility. Sound is brought about by oscillations of an elastic body. In our case by oscillations of the lips, which before blowing are at rest, but on starting to blow into an instrument enter a state of tension which tends towards maximum tension as the notes ascend and back towards the state of rest as the notes descend. For the player this means that every note requires a different degree of lip tension: the higher a note - and thus its frequency - lies, the more his lips must be tensed, and vice versa, as with the strings of a string instrument.