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<DIV><FONT face=Arial></FONT> </DIV>
<DIV><FONT face=Arial size=2>----- Original Message ----- </FONT></DIV>
<DIV><FONT face=Arial size=2>> My opinion is equally firm and 100% opposite
to yours. </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT size=2><FONT face=Arial></FONT></FONT><FONT face=Arial size=3>Hmmm.
The statement above appear to me to be about the only one we really disagree on.
Most everything else you state regarding my last post, I agree
with.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial><FONT size=2>> Household level<BR>> equipment
requires far too much of the owner to be useful. Proper Hivac<BR>>
installations are probably going to cost more than anyone other than the<BR>>
"ultra rich" are able to afford, and certainly more than the cost of
many<BR>> "home size" grand pianos.</FONT></FONT></DIV>
<DIV><FONT face=Arial><FONT size=2></FONT></FONT> </DIV>
<DIV><FONT face=Arial><FONT size=2><FONT size=3>I agree. That is why my home
does not have WRHC and my grand piano is equipped with a DC dehumidification
system. BUT, that is not to say that a DC system is more effective that a
<STRONG><U>proper</U></STRONG> WRHC.</FONT></DIV>
<DIV> <BR>> As I said, it is possible to maintain within 5% but not easy
and not cheap.<BR>> DC units properly installed (and serviced) are
magnificent.<BR></DIV>
<DIV><FONT size=3>Absolutely on both counts.</FONT></DIV><FONT
size=3></FONT><FONT size=3></FONT>
<DIV><BR>>>From a home use point of view a quilted cover may not to be
useful as it<BR>> need to be opened and/or removed when the instrument is
used. String covers<BR>> and bottom covers do stay in place 24/7.<BR></DIV>
<DIV><FONT size=3>Right on.</FONT></DIV><FONT size=3></FONT>
<DIV><BR>> I had "state of the art" controls in two music studios in 1980.
Each studio<BR>> had independent heating, air conditioning, dehumidifier
(drain hose in<BR>> place), and humidifier (self filling, fed from a reverse
osmosis unit). The<BR>> humidity controllers were the most expensive part of
the system and had<BR>> human hair activators, which operated a relay so that
the contacts did not<BR>> have to deal with the relatively large "start up"
surge from the dehumidifier.<BR>> <BR>> As this is a lifetime ago I'm sure
controllers are more sophisticated and<BR>> have narrower limits, but what I
found was that I could not set the "swing"<BR>> from dehumidifier cut in and
humidifier cut out to a very narrow range, or<BR>> both would operate at the
same time--with the humidifier winning "hands down".<BR>> <BR>> It was not
possible to use the studios with the dehumidifiers on nor with<BR>> the air
conditioning. Fortunately the climate where I did this has many<BR>> more
heating months than cooling ones, and more dry months than wet ones.</DIV>
<DIV> </DIV>
<DIV><FONT size=3>Well, I wrote my post this morning. Last I looked it was
the year 2008 this morning. I guess I am guilty of implying that I was
talking about current technology. ;-)</FONT><BR> <BR>> In another
post you mentioned how heat may transfer through the sound board<BR>> panel.
The same thing is true of humidity. </DIV>
<DIV> </DIV>
<DIV><FONT size=3>Yes, BUT.......</FONT></DIV>
<DIV><FONT size=3></FONT> </DIV>
<DIV><FONT size=3>I'm just guessing, based on experience, but not proper
experimentation, that with moderate insulation on the top side of the piano
(a good string cover and a closed lid, let's say) that if the humid room
was 70 degrees (F), you turn on the DC dehumidifier, the air below the
soundboard warms to 90 degrees (just an estimate) and operates
intermittently to keep the temperature at 90, I would expect the string area of
the piano to equilibrate with the heat source maybe at 80 or 85 degrees (really
just depending on how good the insulation was on top) within a few
hours.</FONT></DIV>
<DIV><FONT size=3></FONT> </DIV>
<DIV><FONT size=3>However, if the room is dry and the humidifier kicks on (let's
stuff something in the nose bolt holes to seal those areas off, and let's not
have a Fandrich or Nossaman design with a loose foot), boy, I don't know exactly
how long it would take, but it would be some many days before water molecules
actually migrate through the soundboard from below to the string area. Many
days. Maybe more like weeks or longer. You'd have to have a heckuva seal on the
string environement to trap the slow trickle of water molecules migrating
through that soundboard panel.</FONT></DIV>
<DIV><FONT size=3></FONT> </DIV>
<DIV><FONT size=3>In realistic situations, you can expect heat from below a
soundboard panel to affect the string environment, but a higher humidity
environment below the soundboard will not have any easily measureable effect on
the string environment.</FONT></DIV>
<DIV><FONT size=3></FONT> </DIV>
<DIV><FONT size=3>So I disagree with you on that one, but we didn't address that
in my last post - so I still agree with what you say above as it relates to my
last post!</FONT></DIV>
<DIV><FONT size=3></FONT> </DIV>
<DIV>> That is why upright pianos with<BR>> DC systems installed that have
back covers (I recommend 5 mil poly<BR>> installed by the client) are about 4
times more stable than those that<BR>> don't have a cover.<BR></DIV>
<DIV><FONT size=3>Here also, we didn't address this topic, so I gonna feel free
to disagree with you - but I'll also agree with some of it. </FONT></DIV>
<DIV><FONT size=3></FONT> </DIV>
<DIV><FONT size=3>If I read this correctly, you are saying that and upright back
cover will improve DC system performance because humidity (water vapor) migrates
through the soundboard panel?</FONT></DIV>
<DIV><FONT size=3></FONT> </DIV>
<DIV><FONT size=3>An upright back cover will help quite a bit with DC
dehumidifier performance, but less so with humidifier performance (assuming the
DC system is installed inside the piano - string side).</FONT></DIV>
<DIV><FONT size=3></FONT> </DIV>
<DIV><FONT size=3>An upright back cover improves DC system performance by
isolating the environment of the soundboard rear from the room. If the
dehumidifier goes on, it simply helps to reduce air movement out from that
environment - because hot air rises, the warmed air would tend to escape
quickly.</FONT></DIV>
<DIV><FONT size=3></FONT> </DIV>
<DIV><FONT size=3>If I'm not mistaken, DC does not sell or promote "poly" back
covers (I assume "poly" refers to some sort of plastic). The covers I've seen
from them are a fabric - much like speaker cloth.</FONT></DIV>
<DIV><FONT size=3></FONT> </DIV>
<DIV><FONT size=3>Yes I agree that if you actually seal the rear of an upright
with plastic, you will indeed trap the water vapor in there. Some limited amount
will indeed migrate through the wood, althoughI suspect the majority of water
molecules back there would have migrated through the nose bolt holes. Consider
that with the back sealed up, you will have the necessary weeks, months and
years for the water vapor to get back there. So yeah, I'll buy
that.</FONT></DIV>
<DIV><FONT size=3></FONT> </DIV>
<DIV><FONT size=3>I wonder if there is any danger of trapping too much water
vapor in the rear of the piano with plastic covering the back? Hasn't DC
experimented with that previously? To the best of my knowledge, DC does not
recommend use of plastic as a back cover.</FONT></DIV>
<DIV><FONT size=3></FONT> </DIV>
<DIV><FONT size=3>Terry Farrell</FONT></DIV>
<DIV><FONT size=3></FONT><BR>> At 09:54 AM 2/18/2008 -0500, you
wrote:<BR>>> I have a very firm opinion that whole
room/house/institution humidity<BR>>>control is superior to a standard
DC installation, or even a DC<BR>>>installation with bottom and
string covers. The better the instrument<BR>>>is
isolated from the room, the better the DC can perform
(undercover,<BR>>>string cover, and better yet, a nice quilted cover
with long sides for the<BR>>>entire piano - that is used whenever
the piano is not being played). <BR>>>is
regulated, likely is humidity OUT OF CONTROL. A room with a
Sears<BR>>>dehumidifier with a tank that is not emptied or does not
have a<BR>>>functioning drain for water discharge or a room with
some crude humidity<BR>>>source and likely an even more crude regulatory
device (if any such device<BR>>>at all) is humidity OUT OF
CONTROL.<BR>> Regards,<BR>> Don Rose, </FONT></FONT></DIV></BODY></HTML>