It would be easiest to start with how the two instruments are the same. It’s important to remember that the organ predates the piano by hundreds of years. The piano has become much more popular, in large part due to the fact that they are much cheaper and more portable (though portable pipe organs did and do exist, the large ones are actually built in to their locations). But the layout of the piano keyboard was based on the organ keyboard, and thus the biggest similarity becomes apparent: they both have keys laid out in the same way, with groups of 2 and 3 black keys.

A pianist at work

In similar fashion, they can use the same written music–and for this reason, most organ teachers require that some years have been spent learning to sight-read the grand staff on a piano. (Sheet music for organ generally adds still another staff, another bass clef for pedal notes, but this is not always the case.)

That about wraps up the similarities. To note some of the differences, it is helpful to have a basic idea of how the piano and organ work. I’ll start with the piano, because they are largely standardized: compared to organs, one piano differs from another very little.

Pianos always have 88 keys and 3 pedals (or sometimes only two pedals on inexpensive models). As you can see if you open the top of a piano, it is a string instrument whose sound is produced by little felt-covered hammers that strike when you press a key. The strings are laid out from long to short; hitting a longer string makes a lower sound. If you press harder, the hammer strikes harder, so in effect you have control over how loud or soft a given note is, just by touch.

In fact, each hammer strikes multiple strings per single keypress, to give a fuller sound. If you hold down the leftmost pedal with your foot, you will see the hammers offset themselves, thereby striking less strings per stroke.

The other two pedals have to do with the dampers–the mechanism for preventing strings from continuing to vibrate after they are struck. Especially common is the rightmost pedal, which lifts all the dampers, allowing the strings to vibrate freely and sustain their sound much longer. Use of this pedal is important to a piano player to achieve legato, or a smooth, connected sound between notes.

Organ manuals

An organ, on the other hand, is a different beast. It’s not a string instrument at all, but rather produces sound by moving air through pipes. There is great variety among organs, but they generally have at least two keyboards (called manuals) that you play with your hands, and a pedalboard that you play with your feet (certain portable or very old models may lack the pedalboard or only have one keyboard). The manuals are usually smaller than the piano keyboard by a couple octaves, and the pedalboard has about half the number of notes as a manual (note that the pedalboard is laid out with the same configuration of “white and black” notes).

Example of playing with hands and feet. (Sound in video is quiet; turn it up.)

If you just walk up to an organ no one has messed with and press a key, it will make no sound. This is because you have to tell the instrument which pipes you want to play. You do this by activating levers or buttons called stops. Each stop controls access to a given range of pipes. If the stop isn’t activated, air is not allowed to pass into those pipes.

Pipes are, as you might guess, arranged such that there’s a different pipe for each note. The lower the note, the bigger the pipe. A group of pipes that have the same type of sound and range from the lowest note to the highest is called a rank. Thus, when you pull one stop, you are activating one rank of pipes. If you activate two stops, then two ranks are allowed air, and therefore pressing just one key on a keyboard can actually cause more than one pipe to sound simultaneously.

Ooo... pretty pipes!

This is important, because different ranks of pipes produce different kinds of sounds and different levels of pitch. For example, it’s common to make it so that pressing a key plays the chosen note (say, an A) as well as the pitch that’s an octave above that note (the next higher A). This gives a nice fullness of sound; think about a choir singing in unison: they are singing the same notes, but at different octaves and with different tone qualities, and it provides a more interesting sound than just a group of sopranos.

Similarly, you can activate ranks that will harmonize with the current notes you’re playing. There are also ranks of pipes that emulate different sorts of instruments, like flutes or trumpets. As a result, the organist has much more control over the sound of the instrument than a pianist.

However, due to the difference in how the organ makes its sounds, you can’t make it play louder or softer merely by pressing the keys harder or softer. The pipes are either playing, or they’re not. This means the techniques you use to play an organ differ quite a bit from a piano. Also, the pipes sound for as long as a key is held down, but absolutely no longer. This means that, unlike on a piano, you can hold a note down and it will sound for as long as you want. On the other hand, to achieve legato or a smooth connectedness between notes, you have to play a lot more precisely: you don’t have a damper pedal to do it for you.

vdExample of dynamics on an organ

So, as an organist, you have two ways of controlling how loud or soft your sound is. The main way is, you just activate either more or less pipes. Makes sense, right? But there’s another way: some pipes are always located behind shutters. You can control how open or closed those shutters are with a big foot pedal. So although the pipes themselves always produce the same volume, you have control over how much of that volume reaches the listener.

Shutters in front of pipes - shown here open

Anyway, I hope that serves as a bit of an introduction to the organ. It’s a complex instrument, and one that allows you tremendous control over your sound (which appeals to my gadget-geek nature as well as my creativity). It allows you to make use of all your limbs, giving you access to a whole other melodic line over that of a piano. And it has a unique history and repertory of music behind it. In summary, prepare to get organized.