D/C covers

[Mark Cramer]

I'm curious as well about the use of bottom covers on grands, having
experienced success with backcovers on verticals.

I appreciate Mark's timely reply, as I was just about to try 6ml poly on a
few grands here.

I have installed 4 of the Edward's string covers, but have not realized an
extra margin of climate control from them.

ie:  These 4 pianos "still" experience seasonal swings of about 20 cents
each way, although each equipped with a D-C with 50 and 25 watt bar.

My hunch (all of these pianos are in instituitons) is that air flow is the
culprit.  One instrument that swung wildly, even after several revisions of
the D-C system, has settled down to within 4cts (documented over two years)
since the hall owners agreed to add a near "floor-length" hem to the
existing cover.

I never did determine the source of(ventilation) problems, and at plus or
minus 4 cents, don't feel I need to.

I'm thinking more along the lines Ken does, in that rather than trying to
"eliminate" the free-flow of air (and resident moisture), I'd just like to
"slow it down" to a rate the D-C can easily deal with.

May I go on a bit more here?

In considering the string covers, the reason for their considerable expense
is apparently the cost of "pure" woven-wool cloth.  I priced pool-table
cloth here at $85.99/ yard (CDN) and wasn't guaranteed it wouldn't have some
polyester in the blend.  The manufacturer of the string covers warns against
polyester blend holding moisture in, and rusting strings.

On the back of a piano, the concern isn't as great, and plastic (poly,
mylar, etc.) is probably fine, but I still don't think it needs to be air
tight.  I've had several customers fasten an old wool blanket to the back of
their upright to help the climate system (slow moisture transfer), and found
little discernable difference to tone.

The direction I'm heading with grands, is the D-C systems plus a near
floor-length full-piano cover to reduce draft. I want to test opinion here
(BU)about the concept of rehearsal covers (does such an animal exist?) where
the cover has a deliberate and convenient "half-open" position, allowing use
of the piano without entirely removing the cover.

Any thoughts?

Mark Cramer,

Brandon University