Free reed aerophone: Encyclopedia II - Free reed aerophone - Operation

Free reed aerophone - Operation

The following illustrations depict the type of reed typical of harmonicas, accordions and reed organs as it goes through a cycle of vibration. One side of the reed frame is omitted from the images for clarity; in actuality, the frame surrounds the reed on four sides.

Each time the reed passes through the frame, it interrupts air flow. These rapid, periodic interruptions of the air flow initiate the audible vibrations perceived by the listener.

In a free-reed instrument, it is the physical characteristics of the reed itself, such as mass, length, cross-sectional area and stiffness, that primarily determine the pitch (frequency) of the musical note produced. Of secondary importance to the pitch are the physical dimensions of the chamber in which the reed is fitted, and of the air flow.

Adapted from the Wikipedia article "Operation", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki