Reed pipe

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Diagram of typical reed pipe

A Reed pipe is a type of pipe found in pipe organs qualified by the use of a vibrating brass strip instead of the simple vibration of air, as in a flue pipe.

[edit] Construction

The reed pipe has a metal tongue (the reed) which rests against a shallot and is held in place by the wedge which is made of wood. The entirety of this contraption is held on the underside of the block and hangs down in the boot. As air enters the boot as the stop and depressed key allows, it travels over the reed into the shallot, vibrating the metal strip. The air continues through the shallot which is held in place by the boot, and up into the pipe or resonator. The resonator may be made in a wide variety of shapes and configurations, depending on the type of reed stop, and the timbre desired.

A tuning wire is inserted though the boot and is bent to hold the reed against the shallot. The wire is moved up or down appropriately so as to change the amount of the reed which is permitted to vibrate, thus changing its pitch. The resonator of the pipe is also tuned to be "in sympathy" with the vibrating reed by any of several methods.

[edit] Use

Reeds are designed for one of two purposes in pipe organ builidng: To act as a solo voice (called "solo reeds") or to be used in the full ensemble of stops to add power and sweep to the sound (called "chorus reeds"). A very few reed stops can be used for either function, such as the classic organ-type "oboe". Reeds are generally used sparingly, as the ear quickly tires of a very distinctive tone color, and, by nature, reed stops will go out of tune much more quickly than flue stops. But for carrying a solo melody line, or for true "full organ" effect, they are indispensable. Reed stops are used in the pedal division of the organ in approximately the same ratio to other stops as in the manual divisions.