Indeed, TCLead is correct. A good exercise you can do is to start on the low C or the lowest note you can reach and go up to your high C and then down again. The goal is to have enough air to get from the bottom to the top, it also reinforces the notes you already know. Strong, solid air is the necessity to playing well on trumpet.
Re: Mouth piece sizes - trouble with getting c and above... 12:45 on Saturday, December 23, 2006