<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML><HEAD> <META http-equiv=Content-Type content="text/html; charset=iso-8859-1"> <META content="MSHTML 6.00.2900.3243" name=GENERATOR> <STYLE></STYLE> </HEAD> <BODY> <DIV><FONT face=Arial size=2>Ron said:</FONT></DIV> <DIV><FONT face=Arial size=2></FONT><BR><FONT face=Arial size=2>> Just gluing up any old <BR>> crowned rib set at 6%MC doesn't make it an RC&S board. In <BR>> RC&S, panel compression isn't needed at all to support crown, <BR>> because the number and stiffness of the ribs will support <BR>> bearing without it, so you can leave the panel under less <BR>> (little) compression without compromising longevity. A RC <BR>> design rib set that needs panel compression will, if it <BR>> doesn't get it at assembly, or the panel compression sets with <BR>> time (say 5-10 years?????) and loses the needed support, tonal <BR>> and killer octave problems will develop just like in CC board.</FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2><STRONG><EM>Jude:</EM></STRONG></FONT></DIV> <DIV><FONT face=Arial size=2><STRONG><EM>Ok so I propose that the RC&S is more about the rib design than the emc at rib glue-up. Why can't an RC&S panel be ribbed at a lower emc for the sake of a given climate. There would be some compression in the panel but it wouldn't be necessary to support the panel. Then I could join the club and wouldn't have to skate the issue with my hybrid. Seems it's more about matching a given load with a given resistance.</EM></STRONG> <BR>><BR>> So was that "RC&S" board you trashed just a while ago actually <BR>> an RC board that didn't get or retain the panel compression it <BR>> needed to function, or a true RC&S board, designed as such? Or <BR>> is there something we need to know?<BR></FONT></DIV> <DIV><FONT face=Arial size=2></FONT> </DIV> <DIV><FONT face=Arial size=2><STRONG><EM>Since I didn't hear the pianos in question nor get any real specifics, <FONT size=4>it is just hearsay which I wish to publicly retract.</FONT> I was just very surprised at the source but no matter. Maybe it was an RC board or maybe an RC&S with a mismatched scale design. Can you say that RC&S unto itself precludes that there are other factors that could render tonal problems?</EM></STRONG> </DIV> <DIV><BR> <BR>> It's more stable because the ribs don't react all that much to <BR>> humidity swings, but panel compression does. If panel <BR>> compression is what's holding up the board, you'll have a more <BR>> reactive soundboard than one in which the ribs are holding it <BR>> up. In other words, the reactivity of the component that's <BR>> supporting the board and supplying stiffness will determine <BR>> the stability of the assembly.</DIV> <DIV> </DIV> <DIV><STRONG><EM>Again it seems to be about the ribs not the panel, so what difference does the emc really make in this regard. I think Ric might be right to suggest that post-loading crown Sag is a more noteworthy topic. </EM></STRONG></DIV> <DIV><STRONG><EM></EM></STRONG> </DIV> <DIV><STRONG><EM>And on that note, my board assemblies sag about 30%. </EM></STRONG></DIV> <DIV><STRONG><EM></EM></STRONG> </DIV> <DIV><STRONG><EM>25% crown retention seems a tad soft to me but maybe it's just a different sound if it will hold up.</EM></STRONG></DIV> <DIV><STRONG><EM></EM></STRONG> </DIV> <DIV><STRONG><EM>Ron, you're always the warrior that takes the time to dicuss this and I really appreciate it.</EM></STRONG></DIV> <DIV><STRONG><EM></EM></STRONG> </DIV> <DIV><STRONG><EM>Best,</EM></STRONG></DIV> <DIV><STRONG><EM></EM></STRONG> </DIV> <DIV><STRONG><EM>Jude Reveley, RPT<BR>Absolute Piano Restoration, LLC<BR>Lowell, Massachusetts<BR>(978) 323-4545</EM></STRONG></DIV> <DIV><BR><BR></DIV></FONT></BODY></HTML>