The elements which may be controlled on the rim, the rim width, rim bite radius, rim rise, rim thickness and rim peak position, are all shown on the diagram below.

A wider rim provides a greater contact area for the player and can help when playing for long sessions. The other side of the coin is that a narrower rim enables the player to be more agile when playing rapid passages or over larger intervals as the lips are freer to move, their contact area or restraing area being much less. This may impact upon a player’s range, the narrow rim providing the ability to play over a wider range.

So, a more-rounded rim helps with the comfort but one with a sharper edge or bite helps you to attack the note with more precision.

When buying off-the-shelf mouthpieces, more-roundeded rims are commonly found on deeper cups but, with the PeakTone range you may choose the individual features of your mouthpiece for yourself.

A rim with a fairly flat contour provides for even lip pressure across its surface. It can also provide a good air seal and feel comfortable but it does reduce one’sflexibility.

While rounded rims offer a lot of flexibility, allowing the lips to move back and forth in the cup allowing the player to produce a greater variety of tones and effects they require more lip pressure and more-muscular lips to play. Players who lack the necessary volume of air and a developed embouchure may end up pressing the mouthpiece too hard against their lips, cutting off circulation and loosing the flexibility that might be gained from using a rounded rim, thus defeating its purpose.

What many players, especially beginners prefer, is a medium-wide rim with a semi-rounded contour and a slightly sharp inner edge. This provides sufficient surface for comfortable lip pressure while offering the lip movement needed to produce a wide range of tones.