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<DIV>Hail Dale, (Sorry had to return the rhyme), et al,</DIV>
<DIV> </DIV>
<DIV>I come from the land of a very strict adherence to the doctrine of CC
boards. Speak up if I offend any neighbors here on the list, but I think I
am the only heretic in this part of the land that has abandoned the CC for a
hybrid and even gone as far as experimenting with the RC & S. Currently, I
have settled on a hybrid. I think the primary reluctance to abandon the
lower ranges of MC (3.5-5%) has to do with the knowledge that most households
here range from RH in the low teens in winter to the high 80s in the summer. We
just can't count on our customers maintaining the RH in their piano room, hell
we're lucky enough if we can get them to move their $80,000 investment away from
the fireplace, heating register, window and exterior wall (like my piano for
example, not the price just the situation). We know our wood can withstand the
compression set of the expanding board better than the contracting board so we
ere on that side and deal with the compression ridges. Udo Steingraber also
mentioned that their drying schedule had more to do with protecting the wood
from the driest environs than promoting crown. Some speak of the ethereal
qualities and tonal color that only a CC board can yield but I'll leave that one
alone :).</DIV>
<DIV> </DIV>
<DIV>Using my handy-dandy "Crownulator," [see archives] the other thing I've
noticed is that my traditional CC brethren, that rely on low MC and forced
crowning (i.e. in a dish) to promote crown, end up with way more crown than they
thought. Their go-bar decks may measure 60' radius, but by the time the board is
glued in, they usually have about a 35' to 40' radius which is more than
what I've seen in some rebuilders' boards that are pre-crowning their ribs,
unless of course they are using a more ambitious radius in their rib scale from
the get go, as I am. This is all measured in the unloaded state across
the grain. Loaded states are even more interesting, but I would like to collect
more data before making any statements.</DIV>
<DIV> </DIV>
<DIV>The back bass corner seems to flatten out on all boards due to
the fact that we are all unlimited by the inner rim unless we are
manufacturing our own pianos. This is what really interested me about the
Steingraber's inner rim profile. They also custom taper their boards by placing
sand on each board and tapping the board in the middle until all the
sand moves towards the edges of the perimeter of the board.</DIV>
<DIV> </DIV>
<DIV>I'm not sure how much sense the crowned bridge makes to me or any crown
along the grain. I'm more concerned with the apex of crown being centered under
the load across the grain, and in this regard the Steingraber has a very
symmetrical design. Observe that straight treble bridge (no hockey stick),
placement of impedance devices in the low bass and treble and the bass cut-off
if you get a chance.</DIV>
<DIV> </DIV>
<DIV>The other point I wish to make is that we have to remember that
we're not dealing with one board glued at each end, but rather several
planks glued together and then mounted all the way round. Ron's experiment is a
good one but it would be good to try to repeat the concept of the experiment
using a model that comes closer to a piano soundboard. We should note that
the individual planks within the soundboard have a mind of their own
depending on the grain and how the panels are glued together in
regards to radial and tangential shrinkage. </DIV>
<DIV> </DIV>
<DIV>It is all very interesting, and paraphrasing Udo, how can we expect
one piano to satisfy the whole repertoire from Scarlatti to Thelonious Monk and
beyond. Still, I won't be happy until I can say that this species of wood
with such and such modulus of elasticity, given x amount of load, with y rib
scale and design, and so and so's hammers yield this type of sound. Yeah, dream
on...</DIV>
<DIV> </DIV>
<DIV>Back to work,</DIV>
<DIV> </DIV>
<DIV>Jude Reveley, RPT<BR>Absolute Piano Restoration, LLC<BR>Lowell,
Massachusetts<BR>(978) 323-4545</DIV>
<BLOCKQUOTE dir=ltr
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=Erwinspiano@aol.com
href="mailto:Erwinspiano@aol.com">Erwinspiano@aol.com</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=pianotech@ptg.org
href="mailto:pianotech@ptg.org">pianotech@ptg.org</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Sunday, January 20, 2008 5:20
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: Soundboard drydown for
installation</DIV>
<DIV><BR></DIV><FONT id=role_document face=Arial color=#000000 size=2>
<DIV>
<DIV><FONT style="BACKGROUND-COLOR: transparent" face=Arial
color=#000000><STRONG><EM>Hey Jude dude</EM></STRONG></FONT></DIV>
<DIV><FONT style="BACKGROUND-COLOR: transparent" face=Arial
color=#000000><STRONG><EM> I spoke with Udo
Steingraeber Friday night at a private party/ Reception, in Which his new
& 7 ft & 7inch piano was showcased by five of the most awesome &
prodigious L.A. First call, A list pianists & Jazz players.
BTW...Jude , he confirmed many things you state
below.</EM></STRONG></FONT></DIV>
<DIV><FONT style="BACKGROUND-COLOR: transparent" face=Arial
color=#000000><STRONG><EM> The piano sounded awesome. T'was
Dark, clear & singing & powerful. No duplex scaling behind the
bridge & each backscale length was nice & uniform as it rested on a
half round brass bearing bar. </EM></STRONG></FONT></DIV>
<DIV><FONT style="BACKGROUND-COLOR: transparent" face=Arial
color=#000000><STRONG><EM> I checked the residual treble bearing to be
evenly about 1 1/2 degrees. The rear lengths were ,in my opinion,
adequate for bridge freedom. </EM></STRONG></FONT></DIV>
<DIV><FONT style="BACKGROUND-COLOR: transparent" face=Arial
color=#000000><STRONG><EM> It's tonal pocket is very similar
to what I'm trying to achieve thru an entirely different form of Sound board
building. In my experience any board dried to 4 % before ribbing would show
compression rumpling a cross the panel after stringing but none was in
evidence on this piano. It had 15 taller than wide ribs & a nice sweeping
cutoff bar & aquite a thin panel as best as I could tlel by peeping thru
the nose bolt holes.</EM></STRONG> <STRONG><EM>Udo confirms using flat ribs in
a dish of sorts & palced a big emphasis about crown along the
bridge. In fact he had never heard of checking the crown along the ribs
with a String. I was honestly baffled by this. Certainly a certain
amount of crown is expected across the ribs but perhaps it was all propreitary
which is as it should be.</EM></STRONG></FONT></DIV>
<DIV><FONT style="BACKGROUND-COLOR: transparent" face=Arial
color=#000000><EM><STRONG> </STRONG></EM></FONT></DIV>
<DIV><FONT style="BACKGROUND-COLOR: transparent" face=Arial
color=#000000><EM><STRONG>Whatever. The on going lessons for me are
that, .....many things work & some of them work really well. What I
do know is the piano sounded</STRONG><FONT size=4> truly awesome</FONT></EM>
<STRONG><EM>& personally inspiring & also. It would only
let me play minor key stuff at first & sounded familiar to a certain
D I once rebuilt but .....that's another story.</EM></STRONG></FONT></DIV>
<DIV><STRONG><EM> David & Tanya put on a elegant
& wonderful party for the Steingraeber crew & friends &
he can elaborate as he wishes.</EM></STRONG></DIV>
<DIV><STRONG><EM> Dale Erwin</EM></STRONG></DIV>
<DIV><FONT style="BACKGROUND-COLOR: transparent" face=Arial
color=#000000></FONT> </DIV>
<DIV><FONT style="BACKGROUND-COLOR: transparent" face=Arial color=#000000>As
for Steingraber, they seem to be the only company that is really trying <BR>to
preserve a dome shape to their boards. Not only do they glue a <BR>pre-crowned
treble bridge to an unribbed board, they also custom fit the rim <BR>all the
way round, which makes more sense than assuming a 1 degree angle on <BR>three
sides will yield anything except more stress (not that I'm saying more
<BR>stress is undesirable). The Germans seem to have done copious research on
<BR>stress in soundboards as a tone-producing ingredient, according to Sauter.
<BR>There are many texts in German which have yet to be translated into
English.<BR><BR>The Steingraber bass bridge is attached after the board is
installed because <BR>of the many centemeter variations in the plate casting.
The bass bridge is <BR>therefore hallowed out at the root to allow it to flex
onto the crown of the <BR>board.<BR><BR>Regards,<BR><BR>Jude Reveley,
RPT<BR>Absolute Piano Restoration, LLC<BR>Lowell, Massachusetts<BR>(978)
323-4545 <BR></DIV></FONT></DIV>
<DIV></DIV>
<DIV> </DIV></FONT><BR><BR><BR>
<DIV><FONT style="FONT: 10pt ARIAL, SAN-SERIF; COLOR: black">
<HR style="MARGIN-TOP: 10px">
Start the year off right. <A
title=http://body.aol.com/fitness/winter-exercise?NCID=aolcmp00300000002489
href="http://body.aol.com/fitness/winter-exercise?NCID=aolcmp00300000002489"
target=_blank>Easy ways to stay in shape</A> in the new year.
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