overblowing

In music, a technique of exciting higher harmonics in a wind instrument by increasing air pressure at the mouthpiece, causing it to sound an octave (second harmonic) or twelfth (third harmonic) higher.

The note in an ascending scale at which a player switches to overblowing is called the break point. For instruments of the clarinet family, which overblow at the twelfth, the break point is relatively unstable and difficult to control. Overblowing may occur in organ pipes if the air pressure is too great, but safety-valve devices can prevent this.