Rims

[Mudman]

Does any company produce a stock (ie. inexpensive) Euph/Trom mouthpiece with a 5G-ish cup but a very narrow rim??? If not I might just experiment with an existing Bach...

The Lindberg solo mouthpiece has a sharp and narrow rim, as far as trombone mouthpieces go.

[Lee Stofer]

The rim width needs to work with the other proportions of the mouthpiece, and the player's face. The tuba player must maintain the largest aperture of any of the brasses, and some extra width is needed to properly seal the corners of the embouchure. I have experimented with quite narrow tuba rims, but they tend to make endurance suffer (yes, we do use pressure, and more than a horn player uses), and it can also let the outside corners of the mouth leak air when playing. I find a Kelly 51D to be a very comfortable, good-sounding mouthpiece for euphonium and trombone.

[Chuck(G)]

...and then there are those who take the rim thing to extremes:

http://www.grandcanyontuberadio.com/Rud ... pieces.htm