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Humidity

  • 1.  Humidity

    Registered Piano Technician
    Posted 10-19-2019 19:55
    If we kept our D in a 40%rh space, how long could it be out on a 25%rh stage before noticeable effect?

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    Larry Messerly, RPT
    Bringing Harmony to Homes
    www.lacrossepianotuning.com
    ljmesserly@gmail.com
    928-899-7292
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  • 2.  RE: Humidity

    Registered Piano Technician
    Posted 10-19-2019 19:57
    1 hour?

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    Willem "Wim" Blees, RPT
    Mililani, HI 96789
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  • 3.  RE: Humidity

    Registered Piano Technician
    Posted 10-19-2019 21:23

    Larry,

     

    As with so much, it depends.  Especially it depends on the finish on the board.  Lacquer lets the humidity faster than urethane generally.

     

    But humidity should still take a few days to affect the pitch.

     

    The temperature, however, is another thing.  That's usually where the tuning change comes from when you move the piano out onto the stage.

     

    Don Mannino

    Sent from Mail for Windows 10

     






  • 4.  RE: Humidity

    Registered Piano Technician
    Posted 10-19-2019 23:03
    There is a much faster response when you are going from dry to moist, especially from very dry. I have often seen a D that was stable at 10-20% become noticeably "sour" (unison spread) over night after a sudden rise to 25-30%. Unison smear (right string sharp, left often flat, center between) with a range of a good 2¢, which is a quite noticeable change in sound, a general rise in pitch of about 1¢ average, more at F2 and thereabouts. 

    Once, when I was touching up every morning for a week during recording sessions, the day before the sessions the RH went up. The situation was as above, and I corrected it. Over the course of the week, the RH dropped back to where it was within a day, and the piano was quite stable the rest of the week - only needed the usual minor touch up. I wrote about that here.

    Lights and heat will certainly enter the picture, though, and make changes happen more rapidly in the down direction. And a more drastic lowering can also result in a rapid and large change (thinking back to an experience with a concert Yamaha piano kept in an over humidified store at 60%, going to a venue at 10%. A day later it was awful and needed a major pitch raise).

    The scenario described wouldn't worry me much, unless it was left on stage a few days.
    Regards,
    Fred Sturm
    "I am only interested in music that is better than it can be played." Schnabel






  • 5.  RE: Humidity

    Registered Piano Technician
    Posted 10-19-2019 22:44
    Hi-

    It depends on the piano, but from my experience in similar situations a good piano has a natural resistance to change so it usually takes a couple days before there might be a problem. We have moved pianos on Friday for Sunday concerts frequently without incident.....knock on wood.  

    Dennis. 
    --
    Dennis Johnson
    Piano Technician / Music
    Office: 507-786-3587Mobile: 612-599-6437 
    1520 St. Olaf Avenue Northfield, MN 55057






  • 6.  RE: Humidity

    Registered Piano Technician
    Posted 10-20-2019 22:14
    In general, wood takes on humidity about five times faster than it gives it up. So one has more stable time before a "wet" piano dries out than a "dry" piano gets "wet".

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    Edward McMorrow
    Edmonds WA
    425-299-3431
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  • 7.  RE: Humidity

    Registered Piano Technician
    Posted 10-21-2019 13:45
    Ed - That just explained a lot to me, thanks.

    Don - I know humidity & temperature are intertwined, but my personal experience is that if humidity is stable, temperature can fluctuate & the tuning will be minimally effected. Can you expound on your experience with this?  I think where I live has a lot to do with my perceptions on this topic.

    All - I live in a temperate rain forest, so high humidity is a problem here (not to mention mold). Having said that, I have pianos in unheated churches & even outside that hold tune relatively well, but pianos that go between indoor heating during winter & humid summers suffer greatly.  Can anyone comment on this? If I'm off topic, please PM me or I can start another thread.

    Thanks!

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    Maggie Jusiel
    Athens, WV
    (304)952-8615
    mags@timandmaggie.net
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  • 8.  RE: Humidity

    Registered Piano Technician
    Posted 10-21-2019 14:37
    Hi, Maggie,

    This is a good discussion on the relatively longer-term changes to tunings with humidity change. We deal with this in California a lot, because on this very day, we have a Santa Ana offshore wind blowing which is taking our sort of average fall humidity (and we have MANY sub-climates within a hundred mile radius) go from about 50-60% down to single digits for a few days. Today was predicted to fall to 1 percent. That’s the type of weather when you see our 60-70 mph winds and uncontrollable fires in the news. After a few days or a week, the winds return to on-shore flow and we’re back. (I don’t know what makes our dry air so hard on pianos, but after a nasty Santa Ana most of our pianos are flat, even when it only lasts a few days.) Local newscasters warn us of "Red Flag Warnings" (for fire danger) but to us they’re saying, “Every piano in the city is going out of tune right now”.

    But Don mentions a very quick effect that I deal with often, that of temperature changes to the metal of the wires themselves. This can happen in minutes. Eric Schandall had an excellent demo of this effect. Find a good unison, and gently rub a felt mute up and down one string - not enough pushing to dislodge the string from contact/friction points but it warms it up. You can hear the unison noticeably “out” and as the string cools back off you can hear the unison go clean again. Warming wires are going flat; cooler goes sharp.

    I have run into so many instances where this matters. A good tuning changes when stage lights hit the wires. A good tuning changes when the piano goes outdoors (on one remarkable day in Anaheim last July 2018 it was 114 degrees outside for a jazz concert). Any tuning on a piano with warm or hot strings or plate is absolutely wasted; it will change when the sun goes down. A piano in a hall which was cooled way down for a recording session, which would have air handlers turned off for three days, hit a low of 64 degrees. As the hall gradually warmed up, the pitch kept dropping, and changes were visible with every few degrees of temp.

    I think these sorts of effects aren’t really noticeable on home tunings, when you may not see the piano again for weeks or months. If they turn on the furnace and the air gets warmer and dryer, they may not notice the changes until it gets drastic. It’s visible to you on pianos that you see often, usually for performance situations, recording sessions, and so on.

    Very interesting discussion line. When that cold hall was warming up during the recording session I was trying to track pitch change but it got away from me. I think I was seeing about a cent change for eery degree of temp increase, maybe more. If anyone has occasion to track that, I’d be very interested.

    Kathy




  • 9.  RE: Humidity

    Registered Piano Technician
    Posted 10-21-2019 14:48
    OOOOHHHH! Thanks, Kathy! Got it. I sometimes know when my head is stuck in "country church spinet mode", but it's still hard to pop outside that box without a little help. I'm familiar with all the things you mentioned & I'm back on the same page. Thanks! 😊

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    Maggie Jusiel
    Athens, WV
    (304)952-8615
    mags@timandmaggie.net
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  • 10.  RE: Humidity

    Member
    Posted 10-21-2019 19:47
    I am on the coast of South Carolina and like many places near the coast or bodies of water it is a real challenging environment. I have been servicing a Yamaha C6 for years that has always struggled and I advised them for years to get a Dampp-Chaser system and a string cover to no avail. Proposal after proposal went no where. Last year to I was called to prepare the piano for a US Army Chorus Concert and could not believe what I found on the plate and on the underside beams. White mildew and mold. After testing with mold test strips and discussion with the company using a respirator and proper gloves, eye googles etc wiped off the stains with a professional product and thoroughly cleaned dust dirt etc. It turned out that during the summer the church had completely shut off the ac to tear up carpet , fix plaster and paint. Anyway a new music director arrived and we had the conversation all over. A 100% woolen string cover is now in the piano and after two and a half weeks of data collection with a data logger the evidence is in and they will be getting a Dampp-Chaser finally. The data logger collected readings every five minutes 24 x 7 and the written graphs show that from the beginning the rh never went below 60 % and sometimes was in the mid 60%. One event needs to be examined more closely because the charts show a large spike in temperature and humidity in the span of 24 hours. Perhaps the system was shut off for service or a filter change or maybe the power was out. It is very worthwhile to monitor the piano environment for more than the time you are there tuning. This is the second time I have used a data logger in a church to save their C7 investment. I have gotten used to going into homes and immediately detected a moisture issue either through odor or the damp feeling I get. In one church alone I have installed Dampp Chasers on three pianos that could never hold their pitch and had humidity swollen action parts. Brands where a Yamaha P22, Baldwin Hamilton and a Kimball console. Cold is not a usual issue here although I have been in a church early in the morning with the heat off. You could see your breath but I was there doing a repair on a string. Another time I tuned a grand in a church and it was fine. Hours later when people came and they lit up the wood stove the piano was all over the place. It didnt help that the center pins where loose possibly caused by the drop in humidity and rise in the heat.

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    James Kelly
    Pawleys Island SC
    843-325-4357
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  • 11.  RE: Humidity

    Registered Piano Technician
    Posted 10-22-2019 21:32
      |   view attached

    Hello,

    I agree that temperature is the most volatile and immediate agent of change we deal with on stage.  Lights on/lights off can be nerve racking, especially with harpsichords and fortepianos.  We were able to convince our sustainability folks on campus to fund an LED retrofit of our stage lighting.  They did it for the energy savings (ROI under 7 years), we are ecstatic with the zero change in temperature across all light intensities.

    On a different note, we recently had two of our Steinway S boards (yes, I know, why an S – not my decision) ruined by excess humidity from a localized failure of a steam humidifier system.  We usually stay in the 72 degree/40%RH state, except for our two monsoon months, where the RH climbs to around 55%.  Overall, a nice situation for pianos.  In order to explain to the Risk Management people the damage caused by excess humidity, I put together an Excel document that calculates the dimensional change of soundboards at different temperatures and RH (equilibrium moisture content).  That and an explanation of why soundboards are not permitted to expand due to piano construction, and the subsequent crushing of the wood fibers, it was a relatively easy sell to the adjusters.  I have attached the file if anyone is interested.

    Rick



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    Rick Florence
    Gilbert AZ
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    Attachment(s)



  • 12.  RE: Humidity

    Registered Piano Technician
    Posted 10-23-2019 08:14
    Holy Cow Rick!  That is a really cool spreadsheet!  
    Thanks so much for sharing!


    Debbie Cyr
    Registered Piano Technician
    508-202-2862 cell/text
    debbiecyr@me.com
    www.nbss.edu





  • 13.  RE: Humidity

    Registered Piano Technician
    Posted 10-23-2019 10:24
    Rick,
    Thanks for mentioning retrofit to LED stage lighting. I have been unsuccessful in my lobbying efforts so far for our recital hall, but a couple of the bigger halls I service have done it, and it makes an enormous difference. Besides our own tuning issues, it also means that performers are FAR more comfortable, and the need to have a separate air circulating system for the stage (separate from audience) is eliminated, so there are additional arguments to be made in favor of the expense. Another is the high replacement rate for incandescent stage lights. In our case, someone with a Genie lift has to be brought in, so the expense is contract labor in addition to replacement cost. This is true for the lights above the audience as well (labor costs in particular).

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    Fred Sturm
    University of New Mexico
    fssturm@unm.edu
    http://fredsturm.net
    http://www.artoftuning.com
    "We either make ourselves happy or miserable. The amount of work is the same." - Carlos Casteneda
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  • 14.  RE: Humidity

    Registered Piano Technician
    Posted 10-22-2019 11:22
    I'll second what Ed said.  Pianos absorb moisture faster than they give it up. 

    I tuned a "B" in a recital hall on a Thursday, about 45% RH, stored with a vinyl cover, undercover, and full Dampp Chaser system.  It was moved into a 65% RH theater on Friday afternoon.  Cover removed, lid up.  By Saturday morning, the octaves were a mess, tenor sharp.  I tuned it Saturday afternoon.  Sunday, "they" turned on the air conditioner, and dried the theater to about 45%.  It took a couple days for the pitch to drop.  I tuned again on Wednesday.

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    Greg Graham, RPT
    Brodheadsville, PA
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