Theatre pipe organs use air under pressure (“wind”) both as a prime mover – to open valves, operate percussions, move stopkeys etc. – and as a tone-producer – when blown through pipes. Understandably, therefore, wind is important!
The main components are the blower – which turns atmospheric air into air under pressure (wind), the trunking – which distributes the wind around the instrument, and the regulators – which provide a stable wind pressure irrespective of what the demand is (for example if many or few pipes are being played).
Achieving a satisfactory wind supply is critical to the success of the instrument. As well as the components mentioned above, this success depends on the interaction of other components, especially the windchests and the tremulants.
The layout of the winding system is also critical to the musicality of the instrument; ranks are grouped according to their musical function (and designed pressure) and each group provided with an independent regulator and tremulant.