The tongue has another use in trumpet playing. It can be used as an elevator to get to the upper register or to help quicken slurs and trills as you raise and lower the middle of your tongue. The level of the tongue arch is what affects the range. The syllable Aaah emphasizes the lower notes while Eeeh emphasizes the higher notes.
In order for the same amount or volume of air to pass through your mouth after you raise the level of your tongue arch, it must speed up. The smaller you make the passage, the faster the air goes without any extra pressure. Think about a garden hose when you put your thumb over the end. The more of the hose you covered with your thumb, the farther the water went. This automatic increase in speed is a good, easy way to aid in the production of the upper register.
This will work fine until you reach high C or so.
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