Tone Chamber Style (A, B, or C): The tone chamber of a mouthpiece is the inside area of the mouthpiece. The size and shape of the tone chamber will change the tone quality of the instrument. With the Rico Royal mouthpieces, an “A” tone chamber will give a dark sound which is best suited for concert work, a “B” tone chamber will give a little more brilliance (better for using with most bands), and a “C” tone chamber will give a lot more brilliance and edge which is great for rock and jazz bands.
Facing (3, 5, or 7): The facing is determined by the distance from the tip of the reed to where it first touches the mouthpiece. The bigger the facing number, the farther back the reed goes before actually touching the mouthpiece. Changing the facing of the mouthpiece will generally change the volume of the instrument. With a shorter facing (3), less of the reed is vibrating, so the instrument will tend to be quieter, with a longer facing (7), more of the reed is vibrating, so the instrument will tend to be louder.