DC effectiveness - supplementary question

[Andrew and Rebeca Anderson]

Mark,
All depends on what you mean by "sufficient 
control".  An undercover (speaker cloth) takes 
out air circulation as a factor in overloading 
the DC system.  It essentially establishes a 
controlled climate under the piano.  Possible to 
overwhelm at the extremes? yes.  By a 
string-cover we mean a wool-felt-cover that 
covers everything from the tuning-pin-field to 
the tail end of the piano.  We specify wool felt 
because it naturally buffers humidity.  We 
specify a complete cover because we want to 
establish a loosely controlled climate over the 
board too and as much as is possible unify that 
with the action cavity.  There is a little air 
circulation possible around the bolts through the 
board supporting the plate.  There is also the 
practical situation where humidity does breath 
through wood, thin wood faster.  I too have toyed 
with the idea of drilling some holes through the 
belly-rail but haven't got around to trying it.

In practicality, utilizing both covers does place 
more of the climate under control of the DC 
system.  The extent or preponderance of that 
control has its limits.  One of my piano 
customers bought a limited edition Sauter along 
with the complete system I put on it.  The tuning 
is rock-solid.  The regulation is close (concert 
ready tight) and has not changed.  She leaves the 
lid up on its lowest brass stick.  She also 
leaves the fall-board open despite my advice to 
close it when not in use.  Her ivory keys will 
probably yellow more slowly as a result of that 
preference (not a whole lot of UV getting into 
that room).  Yet, I did have to ease the keys 
during a very humid time here in Laredo.  Under 
the described scenario, there simply was not 
enough climate control to protect the keys.  I 
have not noticed a difference in tuning pin 
torque over the annual seasonal changes this 
piano has undergone with the described system.  I 
have not measured torque to see if there are 
smaller less noticeable changes going on.  I am 
satisfied that this is much better then a piano 
without a similar system as I do have similar 
pianos to compare to without such a system and 
they do undergo noticeable changes.

Ideally the room in which the piano is in would 
have adequate climate control but that would 
require closing it off to the house; not 
desireable or controlling the whole house which 
is not economically feasible.  How much control 
is enough?  In this case the client is satisfied 
with the control we have achieved.

I am satisfied that the action cavity is 
influenced adequately as hammer mating to the 
strings has not noticeably deteriorated with the 
climate swings and Sauters will show this problem 
long before Steinways (high inharmonicity) will.

YMMV,
Andrew Anderson, Artisan Piano--Sales & Service

At 07:31 PM 2/17/2007, you wrote:
>Hi all,
>
>I distribute DC in Australia – where we have a 
>huge mix of climatic conditions, much the way 
>you do in the US but without quite the volume of 
>snow you guys get
! What we are talking about 
>here is frequently brought up by techs here.
>
>I have always pondered the ability of the DC 
>system in a grand to really cover controlling 
>the moisture in a pinblock. In an upright, it’s 
>easy, everything is in the same space. I realise 
>that you are trying to achieve this when you 
>talk about undercovers and string covers and 
>piano covers – unifying the DC controlled space, 
>but how can this possibly be effective for the 
>pinblock when it is so far removed from the 
>system? Having sufficient ‘controlled’ air 
>moving to and surrounding the pinblock to then 
>permeate the block and change the EMC seems 
>almost impossible to me. I don’t have hard 
>numbers on this, it’s merely my bush logic being 
>applied –so I’d value any input at this point.
>
>I know that some years ago Bob Mair at DC played 
>with the idea of holes in the belly rail and 
>computer type fans to circulate air from under 
>the piano into the action cavity and therefore 
>assisting the pinblock too, but this was ruled 
>out due to the extraneous noise factor – it was 
>considered unacceptable by just about everyone who heard it.
>
>Other than that – how can sufficient control for 
>the pinblock be achieved short of a dual tank 
>system in an enclosed piano cabinet?
>
>Looking forward to your thoughts
>
>Mark Bolsius
>

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