Before we get into the how and why of excessive mouthpiece pressure, we need to identify what it actually is and establish how it is produced. What is mouthpiece pressure? When the rim of a brass instruments mouthpiece comes in contact with the lip, it produces mouthpiece pressure on the lip. Some pressure is required in order to seal the two from leaking air as the player begins to blow through the lips. If too little pressure is exerted you will have air leaks. If too much mouthpiece pressure is exerted, the player will limit the vibration of the lips…