Are there any other horn players on the board who have large lips? What mouthpiece do you use? I've had trouble all my life with air leaking out the side of my mouthpiece when I play, and I just read that the reason could be that the inner diameter of my mouthpiece cup is too small for my lips. I always thought it was just because I had a weak embouchure! That still may be part of it, but I really want to try a new mouthpiece. I you have large lips, what mouthpiece do you like? Thanks.

I don't have exceptionally large lips, but I have experienced what you describe. I picked up sousaphone in high school for marching band and couldn't get my embouchure to stop leaking for the first few weeks.

Try changing the amount of pressure you use on the mouthpiece (don't hurt your lips, though!). Rolling your lips in or out may help, as well. It's really just a lot of experimentation, but those two things are what I found to affect leakage in my embouchure the most.

If you have the time and inclination some manufacturers offer the same mouthpiece in larger diameters. Laskey is such a maker, going from very narrow to huge. Houser also offers different sizes in the Standley model. I play the SF Houser in stainless with a mid-60's style Chambers rim he had on file. Another thought that I had is I used to get a tired leak that was happening because of an allergic reaction I was having. Stainless steel is the only product I don't react to. Switching to the stainless suddenly meant that I no longer got a leak after 20-30 minutes of playing. But, I'd try the same model in a few sizes and ship back those you do not like. My lips are moderate with a fair amount of "bow" to the upper one and a 17.5 - 17.75 range works best for me.

If you have the time and inclination some manufacturers offer the same mouthpiece in larger diameters. Laskey is such a maker, going from very narrow to huge. Houser also offers different sizes in the Standley model. I play the SF Houser in stainless with a mid-60's style Chambers rim he had on file. Another thought that I had is I used to get a tired leak that was happening because of an allergic reaction I was having. Stainless steel is the only product I don't react to. Switching to the stainless suddenly meant that I no longer got a leak after 20-30 minutes of playing. But, I'd try the same model in a few sizes and ship back those you do not like. My lips are moderate with a fair amount of "bow" to the upper one and a 17.5 - 17.75 range works best for me.