The diameter of the cup is a very important parameter and must match the player precisely for optimum results.
A cup diameter that is too large for a particular player may cause endurance to suffer, articulations to be sluggish, sound to be dull, poor intonation between upper and lower registers, and range may be severely hindered.
A cup diameter that is too small for a particular player may cause sound to be strained and thin, range to suffer, attacks may split, and the blow resistance will feel very high, almost like the player can not get air through the horn.
Intonation may suffer as well.
When the cup diameter matches the player, flexibilities may be more fluid, attacks improved, blow resistance more comfortable, improved endurance and range.
The main improvements to look for are accuracy, articulation, and intonation.
We at GR technologies, provide you, the player with two cup diameter measurements; r2 and r4.
r2 is the measurement which corresponds with the Series number of each mouthpiece.
For example, the 62 Series measures .620" @ r2. This is where the rim ends and the cup begins.
r4 measurement is taken at .032" down from the rim plane. This measurement indicates the general feel of the cup diameter.