Hygrometer

[Don]

Hi Richard,

For me the proof is not the type of double blind scientific experiment that
I would love to see performed. But empirical data gathered by myself over a
number of years has shown me that an upright piano in my climate (4% to 84%
according to Environment Canada, for inside humidity levels) equipped with
a damppchaser without a back cover will slide about 8 to 10 cents a year at
A4. When the same piano is equipped with a back cover that data becomes 1.6
to 3 cents per year on *any* note. The exception to this data is when the
home has a set back thermostat in use. Then all bets are *off*, and the
piano will be unstable.

The other data I have gathered shows that as a rule of "thumb" a 5% change
in humidity, if the piano is allowed to stabilize, will create a 4 cent
difference in pitch at A4. Again none of this data has been scientifically
gathered. This would mean in your scenario of 45 to 55% a total pitch swing
of 8 cents at A4. Clearly on most pianos this swing would be "amplified" at
the tenor break. The only question left to settle is how fast a piano
reacts. I have some very limited data on this suggesting it takes less than
3 hours, for an instrument to "dry down".

One other point is the obvious smearing of unisons that happens with
humidity change--for this I have nothing but my ears and the few
measurements I have posted on pianotech.
 

At 04:13 PM 9/2/02 +0200, you wrote:
>Don
>
>I see your point,  but you must understand Don, first you said and I quote
>"because of budget problems".... so I took your words at face value.
>
>If you are making the point that no room control system can be sufficient to
>provide a stable enough climate then of course thats another disscussion
>entirely and probably  needs a few qualifiers to make sure we are all talking
>about the same things. For example what tolerances are we operating with. I
>think personally that a damp chaser system would have a hard time improving
>significantly on a room that was always between 45 % and 55 % RH. I could
very
>easily be wrong about this, but if so I would like to know just what studies
>have been conducted that shows this to be true. And I cant see that a system
>that can hold inside climate within these tolerances is going to be quite as
>expensive as you seem to point at. Tho again I could easily be wrong, and no
>doubt this is contingent somewhat upon outside conditions in the first place.
>
>Perhaps this is some of what Roger Wheeler wants to gather data for in his
soon
>to start project which several of us are participating in.
>
>But for the moment, I would think that a room that was constantly within the
>above parameters would be better for a piano, then an uncontrolled room in
which
>a DC unit was the only climate control for the piano.
>
>Of course a DC system is cheaper in the end, and quite a bit so. I dont think
>anyone would argue that. But I dont think that was part of the origional
>question here.
>
>
>
>
>--
>Richard Brekne
>RPT, N.P.T.F.
>UiB, Bergen, Norway
>mailto:rbrekne@broadpark.no
>http://home.broadpark.no/~rbrekne/ricmain.html
>
>
>
>

Regards,
Don Rose, B.Mus., A.M.U.S., A.MUS., R.M.T., R.P.T.

mailto:pianotuna@accesscomm.ca

http://us.geocities.com/drpt1948/

3004 Grant Rd.
REGINA, SK
S4S 5G7
306-352-3620 or 1-888-29t-uner