I focused on temperature in my posts, but the RH effects described by Ed Sutton are very familiar. I find harpsichords 100 - 150¢ sharp or flat after rises or falls of 30 - 40 percentage points (e.g. 20% to 60% to 20%). And I have often enough experienced a harpsichord that was at pitch at my place, falling 10 - 20¢ and more over the course of a week in a drier hall, especially under hot lights. Bottom line is I tune often, and recommend that strongly. And if I have a good inkling that is going to occur, I will tend to tune sharp in anticipation (1 or 2 hz).
This year's rentals have been very mild, with minimal pitch change for some reason, presumably the venues not being as different from my place.
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Fred Sturm
University of New Mexico
fssturm@unm.eduhttp://fredsturm.nethttp://www.artoftuning.com"We either make ourselves happy or miserable. The amount of work is the same." - Carlos Casteneda
Original Message:
Sent: 12-17-2016 08:52
From: Fred Brown
Subject: Humidity and Organ Pipes
Thanks to Ed for starting this discussion. I too am wrestling with matching a harpsichord to a portative organ for Messiah.
It was especially helpful to know the two instruments move in opposite directions with temp changes.
Fred Brown RPT
Jax Symphony
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Fred Brown
Saint Augustine FL
904-687-8353
Original Message:
Sent: 12-16-2016 20:14
From: Ed Sutton
Subject: Humidity and Organ Pipes
I met the organ tuner today. He said the problem is that the organ is underpowered, resulting in pitch changes depending on registration plus a damaged A4 pipe and an organist who keeps trying to adjust the tuning!
The harpsichord is a 1986 Kingston owned by the Charlotte symphony. Two months ago i tuned it last in r.h. 55%. Tuesday it arrived in the other auditorium to 39% r.h., and Wednesday morning I raised pitch 80-110 cents. The heat came on. by Wednesday evening it was 25% r.h. and I raised pitch another 12 cents or so. The weather continued getting colder and the heat stayed on, down to 9%r.h. by Thursday, and pitch continued to drop another 16 cents in 24 hours, so my best guess is to tune about 1 cent sharp about 2 hours before performance, assuming the rate of pitch loss is slowing. If it was harpsichord only, I'd go for 440.5, but here I'm hoping to match the organ.
The Kingston harpsichord is quite a trouper, and is in very good condition despite years of humidity abuse.
I've come to enjoy chasing the pitch around, and will miss doing it. My tuning career in Charlotte ends tomorrow with the last tuning of the harpsichord.
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Ed Sutton
ed440@me.com
(980) 254-7413
Original Message:
Sent: 12-16-2016 15:36
From: Fred Sturm
Subject: Humidity and Organ Pipes
When I have done that (match harpsichord to portative for Messiah) it has been a challenge, because the time window was too tight. Both instruments moved in being on the cold side due to outside weather during transit. Each is going to be moving in a different direction as it warms back up in the hall. If they have a day, or at least several hours, to settle, you have a fighting chance. I'd move in and find the harpsichord was about 10¢ sharp (having had the heat on in the van for the 20 minute trip), and the organ guy would find his instrument 10¢ flat. What to do, with performance in 2 hours, and people coming to warm up in one hour? There is no correct answer. I would leave the harpsichord as sharp as I thought I could get away with (couldn't leave it untuned, as the brass bass strings were considerably out of tune with the rest of the instrument). Grin and bear it. This was a multiple year problem, Sunday matinee done in a church, church not empty until 1 pm. I finally persuaded them to find me a closet to move into the day before.
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