The compressor does not run in the time of playing right ? Or there is some way to silence its noise from propogating through the compressed air to the organ output ?

The compressor does not run in the time of playing right ? Or there is some way to silence its noise from propogating through the compressed air to the organ output ?

Most of the compressors I've seen fill a large air tank. Then from air tank it goes to the organ. The tank is sorta like a barrel sized muffler. Plus add the distance of the line from it (usually residing in basement) to the organ itself.

When there is no noise in the church, you can hear a faint rumble when it is running. The organ playing or the mere presence of even a small group in the church is enough to muffle the noise almost completely.

@FGS the tanks are called reservoirs and they are wood boxes with a cover attached with bellows and a strong spring to keep the cover in. When the reservoir fills with compressed air, the cover rises (and stretches the bellows) and the spring, carefully adjusted, keep the cover floating on the compressed air. There are usually several of these reservoirs. The one at my church has a big reservoir in the basement, right next to the compressor, and at least 4 or 5 smaller ones in the bottom of the organ. Occasionally, the spring on one of them squeaks slightly and can be heard when the compressor runs. The compressor needs to run the entire time the organ is to be played since there are mechanisms that depend on the compressed air besides the playing of the pipes. One part of the organ is completely enclosed and there is a large adjustable louvre that controls the volume. This louvre is controlled by a pedal on the console and is actuated by compressed air. The valves that open to release the air in the pipes is also controlled in part by compressed air. If the power goes out while the organ is playing, you get approximately one second of playing before the lost pressure closes all the valves and the pipes no longer play, even if the reservoirs haven't completely emptied.

When the compressor starts, it takes about 2-3 seconds to fill all the reservoirs and to be ready to play. When it is switched off, it takes about 10 seconds for all the reservoirs to empty. I assume the air goes back in the compressor once the rotors have slowed down enough. The compressor has a damper on the air intake which is held open by a fusible link, just in case of fire.

The organs compressors or blowers run all the time the organ is on and being played.The organ system needs a constant supply of air to work-sound the pipes and operate the air power valves and such.In really older days the organ air system came from hand or foot pumpted bellows.This was an  assistant or appretence organists job!On some modernized air systems the blower motor is on a VFD type device to vary the motor speed according to the air demand on the system.And the VFD help pressurize the system when the blower-compressor is started.-Pressurize it gradually.Blower compressor makers for organs design their blowers to run as quietly as possible.They have multistage blowers and the motors run at low speeds.Like an air tank on a regular 100PSI air system the resevior bellows acts as the air tank-filters out varations in pressure so the wind supply is steady.Often the air systems for some organs are remotely located in another building.The organ in a concert hall in Dallas Tx is this way.It is located in the halls boiler-mechanical building which is next door.Reseviors are used in larger organ systems to equalize pressures in their pipe ranks to keep air demands say from pedal notes from interfering with others.

Classic Rock, 1980's and 1990's rap (Beastie Boys, Will Smith, Fresh Prince, Run DMC, etc. I also like disco and funk. And new wave, rock ballads, hard rock, and oldies like Beach Boys and the Beatles.
Playlist I made of my "Mixtape":


https://www.youtube.com/playlist?list=PLH0kQdklEwTBPQpyp3ACisLF6cwpk2zdj

Oldies:

https://www.youtube.com/playlist?list=PLH0kQdklEwTA-so-gUOF_dS6xEEroGAVv

While we're on the topic of pipe organs, I'd like to share a bit about them. This reminds me of how it's made. I remember 7 or 8 years ago watching a how it's made episode of pipe organs. Thes instruments are enoumous in size, and have extremely intricate on the inner functions. The amount of time, craftsmanship, and effort put into one of these is astounding. In the beginning, you've got a bunch of metal, wood, tubes, wires, etc, and in the end you have a beautifully crafted work of art.

Organs have no standard parts. Very often, when something fails, the organ builder (or repair person) needs to fabricate custom made pieces. The only standard, off-the-shelf supplies are wires and nails and screws. The rest, as Solanaceae says, is metal, wood, felt, leather, etc. that needs to be cut and assembled accordingly. Combined with the lack of space in the organ, it makes for sometimes difficult repairs.

Other organ parts can be obtained-even consoles for replacement.Pipes are made by a small company that can be purchased and voiced,tuned for replacing a damaged pipe.Keyswitches are made by other companies-for new organs or replacements.Offhand don't have the names in mind-have a book at home that lists them.Stop switches are available,too.Other parts of the organ are custom made by the builder or organ erector.Yes,becuase of this is why they are so expensive-but the results are worth it--NO electronic organ can equal the majesty of a piped one!!!Don't beleive it will ever happen,either.New organs have electronic control systems and MIDI-you will see this in new instruments and older ones being renovated.The electronic control equipment is more compact,and often much less expensive.Plus it allows the instrument to be more versatile.A MIDI system can allow the organ MIDI system to "play back" recorded performances.It then could be a self playing instrument!No rolls or music books-but these are still fun!!New band organs play off MIDI-a CD.Some organs have a book or roll player,too so it can be used with either.One company built a MIDI "player" that goes over an existing band organ book player-instead MIDI conversion-the orig book player is kept intact.You can play either existing music books or MIDI.Older instrument collectors and fans appreciate that.Saw that on YouTube sometime back.Clever device!!!

MIDI devices are available for real pipe organs that have fully electronic consoles (two computers, one in the console and one in the organ itself). The sound is still real wind in real pipes, though. The device can record all keystrokes, stop changes, expression pedals, etc and play back the piece as if the organist played it. They are, not surprisingly, very expensive.

Nothing beats the sound of real pipes playing, whether by a manual traction console or by an electronic console. The advantage of the electronic console is the very simplified wiring (a standard CAT5 cable with RJ45 plugs, if I remember correctly) so that means the console can be mobile and changed from the front to the back of the church, etc. Manual and electropneumatic consoles cannot be moved around.