Tone is produced by injecting air into the mouthpiece. What tones will be produced depends on how the column of air is introduced into the mouthpiece. Vibration of the upper lip is necessary to produce good tone. The higher the tone the more rapid must be the vibrations. But lip vibration does not suffice.

The low tones are produced by relaxing the lips and sending the column of air against the lower part of the cup. The medium tones or middle register are produced by slightly tensing the lips and directing the air straight through the hole at the bottom of the cup. The upper tones are secured by throwing the column of air higher into the mouthpiece. This tenses the upper lip and produces non vibration than for the middle tones. The higher the tone desired the higher the air must be directed into the mouthpiece. For the extreme high tones the column of air must strike near the upper part of the cup - nearly at the rim.This further tenses the muscles of the upper lip and produces more rapid vibrations.

In ordinary mouthpieces in order to produce the high tones without resorting to the old hard-pressure system the performer usually relies on a shallow cup mouthpiece. This invariably results in the impairment of tone quality in the middle and low register.