First, we need to understand what exactly a pipe organ is. Simply stated the pipe organ is a big box of whistles. Each one of these whistles sits on top of a hollow wind chest which is filled with air by a blower or bellows. Th wind chest also contains a series of valves connected to the keyboard via a linkage system. These valves or pallets as they are called, control the flow of air to each pipe. The keyboard of console contains what are known as stops. Each stop represents a set of pipes called a rank. Each rank plays a different tonal sound. Basically, what occurs is a key is pressed, the keys mechanically linked pallet opens, the compressed air travels through the pipe, and a beautiful sound is made.
How does air make sound?
Sound is air vibrating. When you remove the cap a exhale air across the top of a soda bottle you get the same effect – it makes a note. One organ pipe will produce one tome at one pitch. Unlike other instruments such a s flute you cannot manipulate pipes to play multiple note. One pipe equals one not. On a standard 61 key, keyboard there will be 61 individual pipes each creating their very own note.
How does the keyboard control the pipes?
The pipes produce sound when air is blown into the foot or bottom of the pipe. This is caused by release of air from a special chamber called the wind chest. The wind chest has a separate channel or valve for each pipe. Here’s how it works. As the organist presses down on the low C key on the keyboard, special linkage open the low C valve in the wind chest, air is released into the foot of the low C pipe and the organ plays low C note. On a 61-note keyboard, there are 61 valves which 61 pipes sit on top of. Each of these 61 valves is opened and closed as the organist presses and releases the keys of the keyboard.
What sounds can an organ make?
The pitch of the sound coming from each pipe is determined by the length of the pipe. This is very similar to how stringed instruments work. A shorter string produces a higher pitch than a longer one. Thus, a short pipe produces a higher pitch than a long pipe. Let’s go a little deeper. When a piano produces a Middle C it takes a two foot organ pipe to produce the same sound. When the length of the pipe is doubled, the pitch goes down one octave. To produce a Tenor C you would have a four foot pipe, for a Bass C, an eight foot pipe.
Why do organs have several keyboards?
We have been talking about the main 61 note keyboard. The second keyboard controls a second set of pipes. These pipes traditionally lighter tone and are an octave higher than the first set of pipes.
How are pipes made?
Pipes are constructed by taking tin and lead and melting them into a liquid in an iron pot. This liquefied metal is than poured out onto a table to cool and form into a thin sheet. Rectangular pieces are next cut out of the sheet. These pieces are next rolled into a tube. The tube is completed when the foot mouth are added making each tube the whistle we know as a pipe organ.