The hygrometer accuracy, is not as important, as is thought. (I didn't mean large error) It is a relative thing, you would be comparing with your previous reading with the same instrument. I realize there is a degradation over time as the sensor gets contaminated. John M. Ross Windsor, Nova Scotia, Canada jrpiano at win.eastlink.ca ----- Original Message ----- From: "Kent Swafford" <kswafford at gmail.com> To: "College and University Technicians" <caut at ptg.org> Sent: Friday, November 16, 2007 3:37 PM Subject: Re: [CAUT] Hygrometers > These consumer hygrometers do not provide scientific accuracy, but > they sure seem good enough to me. > > I use an older version of this: (Translate; I bought when they were > more expensive.) > > http://tinyurl.com/2ofyd2 > > In a grand piano with a climate control system, I have one of these > hygrometers on a shelf across from the piano; one remote sensing unit > is below the soundboard of the piano, and another remote sensing unit > is in the piano above the soundboard. (The piano has both bottom and > top covers.) The hygrometer set-up gives a rather dramatic > demonstration that the climate control system is working; it is a very > comforting thing to know that when the room RH is low 70's that the RH > in the piano can still be in the high 40's. This can provide very > strong evidence of the efficacy of piano climate control systems. > > Kent Swafford > > > On Nov 16, 2007 8:07 AM, Paul T Williams <pwilliams4 at unlnotes.unl.edu> > wrote: >> >> Hi Jeannie! >> >> Good to hear from you! >> >> That's an interesting observation on the cheapie vs. fancy-schmancy. >> Maybe >> that "relative-relative" reading is all that I need. I still don't >> understand why that one particular room feels so muggy, yet doesn't >> register >> high on the hygrometer. Maybe I have a lemon? >> >> Best, >> >> Paul >> >> >> >> "Jeannie Grassi" <jcgrassi at earthlink.net> >> >> Sent by: caut-bounces at ptg.org >> >> 11/15/2007 09:23 PM >> >> Please respond to >> College and University Technicians <caut at ptg.org> >> >> To"'Ed Sutton'" <ed440 at mindspring.com>, "'College and University >> Technicians'" <caut at ptg.org> >> >> cc >> SubjectRe: [CAUT] Hygrometers >> >> >> >> >> >> >> >> >> Hi Ed, Paul, et al, >> I recently bought one of the "Professional" hygrometers from Pianotek >> because I had heard the same comments from several other people. Well, >> for >> the past two months I've been using it side by side along with a >> Dampp-chaser hygrometer a/o ones that my clients happen to be using. I'd >> like to say that the small difference in RH that it reads hardly amounts >> to >> anything. AND……it takes quite a while (like five minutes) to settle down >> and give an accurate reading from what it registered in my case, in my >> car, >> traveling from the last appointment. >> >> At first I would smugly take a reading off of it immediately and was >> surprised at what a different result it gave from what was in the piano. >> I >> congratulated myself on upgrading my tool and being a true "professional. >> However, one time I just let it sit there while I was tuning and noticed >> how >> much it changed until it ended up with almost the same as the one in the >> piano. I observe this every day now. And I'm asking myself why I spent >> all >> of that extra money. One client proudly showed me his thermo-hygrometer >> (with memory) that he bought at Walmart for $6. It read the same as my >> fancy-schmancy "professional" one. >> >> Comments? ;>) >> jeannie >> >> >> ________________________________ >> >> From: caut-bounces at ptg.org [mailto:caut-bounces at ptg.org] On Behalf Of Ed >> Sutton >> Sent: Thursday, November 15, 2007 3:05 PM >> To: College and University Technicians >> Subject: Re: [CAUT] Hygrometers >> >> How about the "Professional" meter that Pianotek sells? >> I like it because it reads quickly and reads lower RH than the Radio >> Shack >> types. >> I haven't compared it to a sling psychrometer. The sling psychrometers I >> have found were rather expensive. >> Ed Sutton >> >> ----- Original Message ----- >> From: John Musselwhite >> To: College and University Technicians >> Sent: Thursday, November 15, 2007 4:41 PM >> Subject: Re: [CAUT] Hygrometers >> >> At 12:42 PM 11/15/07, Paul wrote: >> >> >> Hi List, >> >> I have a couple of those cheap max-min thermo-hygro readers from >> Pianotek. >> I'm not sure if they're very accurate. >> >> They're more accurate than the Radio Shack ones, but I don't think by >> much. >> >> >> If you all remember, last fall/winter I sent in some photos of one of our >> recital rooms that Richard West took before I got here with the fog and >> water dripping all over everything. It hasn't been that bad since I've >> been >> here, but the last couple of times I've gone in there this past week, it >> feels really muggy, but the hygrometer only registers 40-45% (which would >> be >> ideal). Any suggestions on who makes a real accurate reader? >> >> We have the opposite problem here where Rh can be down into the single >> digits in mid-winter. None of the "standard" humidity gauges go down that >> far. I use a Cooper Digital Psychrometer much like the one down the page >> at >> http://www.techinstrument.com/acatalog/Hygrometers__RH___humidity_.html >> (SAMJR995). It's a digital version of a "sling psychrometer", the wet/dry >> bulb unit we use to make truly accurate RH readings. While it's >> supposedly >> accurate +-5% it still reads down to zero Rh which in worst case might >> actually be 5%. I've read as low as 3% in mid-winter here in some >> churches. >> In those pianos with DC's installed, sticking it under the rim for a >> minute >> and pressing the "hold" button shows it's in the 40-43% range at the >> soundboard even with extremely low humidities outside the instrument. >> >> I also have a USB recording hygrometer that will track the RH and temp >> over >> a long period of time. It's at >> http://www.measurementcomputing.com/cbicatalog/USB-502.asp?dept_id=414&pf_id=1759 >> . It reads very much like the "standard" units and differs from the >> Psychrometer's readings. I trust the Cooper more for truly accurate >> readings. >> >> John >> >> >> ------------------------------- >> John Musselwhite, RPT - Registered Piano Technician >> Musselwhite Piano Services - Calgary, Alberta Canada >> Office/cel (403) 246-7717 Fax (403) 255-5268 >> Outside of Calgary call Toll Free: 1-866-95-PIANO (1-866-957-4266) >> "Three Generations of Experience" >> >
This PTG archive page provided courtesy of Moy Piano Service, LLC