<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <meta http-equiv="Content-Type" content="text/html;charset=ISO-8859-1"> <title></title> </head> <body text="#000000" bgcolor="#ffffff"> Adjustability comes to mind. You can come only so close to the optimum amount of stiffness in the different areas of the board when choosing panel and rib materials and dimensions, and that stiffness may change as the panel ages. So magnets would allow for a fine tuning, no? Tom Cole David Love wrote: <blockquote type="cite" cite="mid000601c53f09$2d39b7a0$6501a8c0@DFCX0Y11"> <meta http-equiv="Content-Type" content="text/html; "> <meta name="ProgId" content="Word.Document"> <meta name="Generator" content="Microsoft Word 10"> <meta name="Originator" content="Microsoft Word 10"> <link rel="File-List" href="cid:filelist.xml@01C53ECE.7D023950">  <style>  </style> <div class="Section1"> Why would this be better than simply creating a rib crowned and supported panel that can be compressed to the requisite stiffness through the use of downbearing without overstressing the panel?<o:p></o:p> <o:p> </o:p> <div> David Love <a class="moz-txt-link-abbreviated" href="mailto:davidlovepianos@comcast.net">davidlovepianos@comcast.net</a> <o:p></o:p> </div> -----Original Message----- From: <a class="moz-txt-link-abbreviated" href="mailto:pianotech-bounces@ptg.org">pianotech-bounces@ptg.org</a> [<a class="moz-txt-link-freetext" href="mailto:pianotech-bounces@ptg.org">mailto:pianotech-bounces@ptg.org</a>] On Behalf Of <a class="moz-txt-link-abbreviated" href="mailto:Erwinspiano@aol.com">Erwinspiano@aol.com</a> Sent: Monday, April 11, 2005 6:34 PM To: <a class="moz-txt-link-abbreviated" href="mailto:pianotech@ptg.org">pianotech@ptg.org</a> Subject: Re: Virtual Ribs, A new crown support method <o:p> </o:p> <div> <div>   RIc<o:p></o:p> </div> <div>   May the force? be with you brother.grin<o:p></o:p> </div> <div>   Dale<o:p></o:p> </div> <blockquote style="border-style: none none none solid; border-color: -moz-use-text-color -moz-use-text-color -moz-use-text-color blue; border-width: medium medium medium 1.5pt; padding: 0in 0in 0in 4pt; margin-left: 3.75pt; margin-top: 5pt; margin-bottom: 5pt;"> Hi folks After a few months of experimenting, I am ready to announce a new (I believe)  method of supporting crown for any type of soundboard. The method allows for both restoring crown and supporting it in older panels, and designing new panels in which the concerns of mass levels and degree of assembly stiffness can be to a far greater degree treated independantly. In essence, an array of repelling high power neodym magnets of appropriate dimmensions and strengths are used to support crown against downbearing from the strings. One set are imbeded in soundboard button similar wooden sheaths and are attached to the soundboard with glue and screws.  Opposing these is another set which are mounted into a very strong wooden beam such that their distance from the soundboard attached magnets can be adjusted easily from below.  One can either choose to simply provide support directly under the bridge, or without too much difficulty, contrive what amounts to a system of virtual ribs with fully adjustable support for crown. For edification... Neodym magnets that measure 30 mm Ø by 5 mm thick can hold / push approximately 25 kilos.  Since there is no phsyical connection between the soundboard and opposing magnets, the assembly is not directly mass loaded. Hence stiffness and crown support is provided without mass loading. More later on as I formalize an article on a working example I am hoping to finish soon. As is my habit... this is an open source idea, I encourage any and all to take up and refine it in their own fashion.  My own initial results indicate that the principle is very successful. Cheers Richard Brekne<o:p></o:p> </blockquote> </div> <div>  <o:p></o:p> </div> </div> </blockquote> </body> </html>