Hi Garret,
I tuned the pianos six or more times a year. The two grands with systems installed, Steinway Bs in the head piano prof's office, would typically have a pitch change that would be 25¢ sharp after the summer RH rise to 60% around the beginning of August for the low tenor strings (maximum pitch change). That would then reverse during the rest of the year.
The other piano, the RX2 with the beta test system, would typically have 40¢ pitch excursions at the low tenor, and unison pattern left/right string variances of 10-15¢ in octaves 5 and 6 (less in other areas).
That is what I would face before the semester began. Tunings were timed so that subsequent periods would have far less extreme tuning problems. But that was the general pattern for all pianos under my care, for the 35 years I worked there. Typical RH cycle of 10% or under in the winter, 60% in late summer/early fall. I'm sure others have wider extremes.
Original Message:
Sent: 3/6/2026 7:32:00 PM
From: Garret Traylor
Subject: RE: CAUT Dust Collection/Humidity Control
Hi Fred
In your particular case, how frequently did/do you see the piano and what is the expected cent/pitch deviation?
- Garret
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Garret Traylor
Trinity NC
(336) 887-4266
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Original Message:
Sent: 03-06-2026 17:40
From: Fred Sturm
Subject: CAUT Dust Collection/Humidity Control
Robert,
You also asked about humidity control. In my own experience with Dampp-chaser systems I found that they were not very effective in controlling RH associated tuning swings, particularly in grands. I did find that installing just a low RH humidistat and heating rods in uprights made a noticeable difference - definitely helpful - but note that that is a closed space which includes the bridges.
I installed full systems in two grands in a high priority piano prof studio, and its effect was pretty minimal. Adding an undercover made little if any difference.
I participated in a beta test of a new system maybe 15-20 years ago. It sealed the bottom of the piano with plastic (taped to the bottom of the rim with duct tape), and included sealing the nose bolt holes with foam. A data logger within the sealed space showed an amazingly steady RH. I had a humidistat set to 35%, and it deviate no more than + or - 1% from that standard. This was installed on a Kawai RX2, one of the most RH sensitive pianos in my inventory, with the usual unison phenomenon (difference between right and left string of the unison) and plate strut issues (tenor and different sides of treble strut).
Result: I didn't notice any perceptible difference in the type or size of the pitch migration pattern. Once I had established that over the period of a year, I started experimenting with string covers, first using the open weave of under covers, then using a fairly thick pure wool cloth. Again, not effective. When I logged the RH under the cover and compared it to ambient room RH, I found next to no difference. I concluded that probably most of the RH associated pitch swing phenomena probably occur at the bridge by some as yet undetermined mechanism (I suspect the bridge pins moving with the wood, hence changing the degree of offset as the string crosses the bridge, is part of the picture). That is, if keeping the RH at the bottom of the soundboard very stable made no perceptible difference, it couldn't be the soundboard that was the major factor. What's left? The bridge. (Well, and, the pinblock, but I had eliminated the pinblock as a factor many years earlier, at least for the unison drift issue)
I was frankly very surprised as well as disappointed. In any case, I came to believe in controlling the room RH as really the only effective option.
This was in a building with a fairly robust HVAC system (no functioning RH control - originally installed with one, but had died before I came on the scene), so the air exchange is pretty rapid, as is typical in almost all public buildings.
I suspect others may have other experiences, but those are mine FWIW, over a period of 30 years. Experience with private clients is similar, though I never see those pianos as often, so know less of what happens seasonally.
Original Message:
Sent: 3/6/2026 11:05:00 AM
From: Robert Wilkinson
Subject: RE: CAUT Dust Collection/Humidity Control
Hi David,
Those are great questions!
We do a lot of action rebuilding in our shop, so a few saws and sanders are the main source of dust, and chemical/glue fumes as you mentioned from gluing hammers on WNG shanks, doing minor finish repairs, and whatnot.
I don't have a dream really other than making it better, and I brought it to my boss who asked me to do some research on what other universities do in their shops. I guess a centralized system would be ideal, but that seems expensive and impractical.
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Robert Wilkinson RPT
Rochester NY
(706) 945-4496
Original Message:
Sent: 03-04-2026 09:34
From: David Skolnik
Subject: CAUT Dust Collection/Humidity Control
Cheapest way to go, at least in the short run, is "thoughts and prayers". Otherwise, it would help to be more specific, as your 'short' question accommodates much of existence as we know it. Are you asking about practice rooms for Dampchasers/humidifiers or shop or performance spaces? What sort of existing ventilation do you have? A central system would severely limit the efficacy of a local humidifier. The type of space and existing levels would be useful to know.
As for dust, the question is: what are you doing or wanting to do? What kind of shop operations are you doing or hoping to do? You would want to be able to accommodate cleaning, hammer filing, wood dust generated by either hand or machine operations, aerosolized materials such as chemicals, glue fumes, etc. Also want to have flammable storage under legitimate control.
So, what's your dream?
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David Skolnik [RPT]
Hastings-on-Hudson NY
(917) 589-2625
Original Message:
Sent: 03-04-2026 08:49
From: Robert Wilkinson
Subject: CAUT Dust Collection/Humidity Control
Hi CAUT members!
I am trying to do some research about what other schools are doing for 1) Dust Collection/ventilation in their shop 2) Humidity control.
If you have a woodshop/workshop for your university (or even at home), what is your method for dust collection?
Especially for people in low-humidity environments, do you use Dampp- Chaser's? Room Humidifiers? Thoughts and Prayers?
Thanks!
Robert
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Robert Wilkinson RPT
Rochester NY
(706) 945-4496
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