Wind chests
I wired my first wind chest last week. A wind chest is the box that controls airflow to a rank, or perhaps several ranks, of organ pipes. Organ technology relies on several kinds of mechanism, all of which involve differences in air pressure, and I'm only beginning to understand them. For hundreds of years the mechanisms were purely mechanical, and some good pipe organs still operate that way. Nowadays most of the controls involve electronics and magnets.
On Friday while making some minor repairs to an organ at Church of the Holy Saviour in Waterloo, Les replaced what looked like a large motherboard and several components, inserted one on top of the another. But it was not a motherboard. Les explained that particular organ still uses fairly basic electronics involving only diodes and resistors, no transistors; which is French to me, familiar but barely comprehensible. The delicate controls only look like organ components because there are so many circuits to control, so many wires to connect.
A handful of newer pipe organs around the world are now computerized, but with so few machines to experiment on, the technology evolves slowly.
Our friend John came from London, Ontario to help with the wind chests, as he has much more experience. He spent the entire week completing three chests, each containing dozens of new valves and electromagnets (upper photo). This is part of the renovation of the organ from Geneva Presbyterian Church in Chesley, which has been most of our work so far this year.
John may have played a role in persuading Les that I could do this work, too, which is good experience for me, of course. On Thursday Les got me started on one big chest destined for the new organ at St. James Anglican Church in Dundas, our biggest project for 2007. The chest will control the largest pedal pipes, so there are relatively few, only 30. This gave me lots of space to learn how to install the delicate mechanism (lower photo).
Wires to the chest are colour-coded, so we can see which key connects to which pipe when it comes time to install everything. Playing a key (or in this case depressing a pedal) sends an electric current to the corresponding electromagnet, one of the small white cylinders, which pulls the lever below and closes the valve in the circular hole. This is called an exhaust valve. I'm still foggy about how closing it directs air into the pipe, but this involves changing air pressure. The round holes above the magnets in this photo are part of an obsolete mechanism in the old chest (part of this organ has been donated by another church), and will no longer be used.
From studying the photo of John's work, I see those magnets actually open the valves, so this is a different mechanism, apparently sending air directly into the pipe.
The hardest part of my job was screwing the round plastic nuts, those little white stars, onto the pins that hold the valves, and then carefully balancing the tension of each mechanism. I'm developing a worker's hands. My fingers are calloused, one thumb cracked and sore.
My energy is shifting drastically, bewilderingly. At work I'm happy and focused, but sometimes I arrive home at 5:30 more exhausted than I can ever remember. I'm becoming fairly disciplined about going to bed at 11:00 so I can get up at 6:30. I can't get moving quickly, need 90 minutes to casually shower, eat breakfast, write morning pages and perhaps knit for a few minutes before work. So yes, I am writing. It will take some time to figure out how to focus and harness that to produce poetry, fiction or essays.
On weekends and days off I am unusually energized and focused. But this all depends on getting seven-and-a-half hours' sleep. If I slip, stay up late even one night, it all falls apart and takes several days to recover.
DREAM: I lay down Friday night thinking about a conversation I want to have with Brenna, wanting to find out how she really feels about things going on right now. Drifting off to sleep, I had a lucid dream about walking with her into a huge white, domed room like the artists' school in Tea With Mussolini. The roof of the dome was soft grey, alive and electric, with faint fireworks erupting in the stone. I pointed out large objects standing here and there on wide marble steps around the edges of the space. Some seemed to be half sculpture and half pipe organ. I began explaining their mysteries to her.
