How church organs work - pipes, ranks, stops, and the console
Church organs are pipe organs. Their sounds are generated by passing wind, under pressure, through pipes, which generate their sounds just like a flute or a recorder. Some organ pipes contains reeds and resonators, allowing them to produce harsher, more harmonically-rich sounds than pure flute tones, reproducing tones reminiscent of clarinets, oboes and violin. The amount of stuff in even a small church organ is remarkable - a typical small chapel organ will contain more than 500 pipes, allowing dozens or even hundreds of flute-like / clarinet-like instruments to be sounding, all at the same time. For some 9 centuries pipe organs reigned supreme as the most complex pieces of technology, with the most moving parts, ever built by humans. They are truly magical things.
Ranks
The pipes of a church organ are arranged into ranks, which are sets of different-sized pipes - different sizes to give different pitches - forming a single 'voice'. The pipes within a rank all sound pretty much the same - the 'Clarinet' pipes all sound like Clarinets - but each plays at a different pitch, and these ranks of pipes are turned on or off by the use of 'stops'. The sound generated by an organ at any time is a summation of the sounds of all the ranks of pipes that are 'speaking' - organ-speak for 'making a sound'.
Stops
Stops are push-pull controls on the organ's console, and the word 'stop' is used interchangeably to mean the thing you pull out to make a sound, or the sound that is generated when that thing is pulled out. So 'the clarinet stop on this organ sounds particularly sweet' is just as valid as 'the clarinet stop on this organ is really hard to push in today, I think somebody spilled coffee on it'.
The Organ Console
The user interface of Victorian Chapel Organ presents a stylized version of an organ 'console', which the UI of a real church organ, with a graphical representation of each stop. When you touch a stop on screen - e.g the Recorder 8' - that will 'pull out' or 'push in' that stop, enabling or disabling that rank of pipes for generating sound.
So - what does 8' mean?
The ranks are always referred to in 'feet' - the 8' 4' etc. indicate the length of the lowest-pitched pipe in the rank. 8' or 8 feet is a pretty long pipe, so an 8' rank will sound an octave lower than a 4' rank, and a 16' rank an octave lower than that. 16' is REALLY long to fit into a small church, so via the magic of physics and acustics 19th century organ builders worked out how to make pipes sound an octave lower than their physical length, so a real organ's 16' pipes may in fact be only 8 feet in length.
One word of warning - with no stops pulled out, the organ will make no sound. This may confuse you. If you are playing the organ and no sounds are coming out, read the FAQ and troubleshoot your sounds!
Next - how the organ is split into 'Divisions'
Ranks
The pipes of a church organ are arranged into ranks, which are sets of different-sized pipes - different sizes to give different pitches - forming a single 'voice'. The pipes within a rank all sound pretty much the same - the 'Clarinet' pipes all sound like Clarinets - but each plays at a different pitch, and these ranks of pipes are turned on or off by the use of 'stops'. The sound generated by an organ at any time is a summation of the sounds of all the ranks of pipes that are 'speaking' - organ-speak for 'making a sound'.
Stops
Stops are push-pull controls on the organ's console, and the word 'stop' is used interchangeably to mean the thing you pull out to make a sound, or the sound that is generated when that thing is pulled out. So 'the clarinet stop on this organ sounds particularly sweet' is just as valid as 'the clarinet stop on this organ is really hard to push in today, I think somebody spilled coffee on it'.
The Organ Console
The user interface of Victorian Chapel Organ presents a stylized version of an organ 'console', which the UI of a real church organ, with a graphical representation of each stop. When you touch a stop on screen - e.g the Recorder 8' - that will 'pull out' or 'push in' that stop, enabling or disabling that rank of pipes for generating sound.
So - what does 8' mean?
The ranks are always referred to in 'feet' - the 8' 4' etc. indicate the length of the lowest-pitched pipe in the rank. 8' or 8 feet is a pretty long pipe, so an 8' rank will sound an octave lower than a 4' rank, and a 16' rank an octave lower than that. 16' is REALLY long to fit into a small church, so via the magic of physics and acustics 19th century organ builders worked out how to make pipes sound an octave lower than their physical length, so a real organ's 16' pipes may in fact be only 8 feet in length.
One word of warning - with no stops pulled out, the organ will make no sound. This may confuse you. If you are playing the organ and no sounds are coming out, read the FAQ and troubleshoot your sounds!
Next - how the organ is split into 'Divisions'