<!doctype html public "-//W3C//DTD W3 HTML//EN"> <html><head><style type="text/css"></style><title>Re: compression ridges in New Baldwin grand</title></head><body> <div>Folks,</div> <div><br></div> <div>Having just completed two months of testing sound board test strips, ie. one rib mounted to a strip of sound board<font color="#0000FF"> (a series of RC variations and a CC control group was built, testing them with a range of down bearing loads and plotting each for panel deflection along the length of the rib)</font>, I find the debate on this thread to be a bit frustrating.</div> <div><br></div> <div>An analysis of the loads on a typical sound board will reveal that by far the most highly stressed ribs are those in the second last treble section. This is why the 'killer octave' phenomenon<font color="#0000FF"> (which perhaps could be better named the 'collapsed sound board section')</font> is so frequently encountered here and rarely elsewhere on the instrument. The ribs in the lower sections are progressively less stressed, while in the top string section the bridge runs so closely to the belly rail that it is supported to a significant degree by its proximity to the belly rail.</div> <div><br></div> <div>I have difficulty accepting Richard B's argument, that because a greater percentage of the world's performance pianos come from one maker, this manufacturer's technique must therefore carry legitimacy. I am unconvinced about drawing conclusions from this market dominance theory and would prefer to arrive at a view through experimentation<font color="#0000FF"> (and would commend the practice to others who feel compelled put forward an argument)</font>. While it is always difficult to determine a truth, we must persevere since an answer will be forthcoming if we allow ourselves to consider the options.</div> <div><br></div> <div>At this time I am convinced that rib crowning is structurally superior to compression crowning. While I believe that both are capable of producing a quality tone, the CC design is absolutely bound to fail earlier than the RC design.</div> <div><br></div> <div>I note also that some doubt was cast upon Ron N's assertion that some pianos have collapsed sound boards before they reach the showroom floor. Could I suggest that those who doubt Ron's claim actually take measurements from a few new pianos. When Ron first made this claim on the list some months ago, I measured several new instruments only to find that he was absolutely correct. Currently, I  know of two new grand pianos here in Sydney which are being returned to the manufacturer next week before being delivered to the showroom. With plenty of down bearing, an almost perfectly flat board and a choked tone, these pianos are glowing examples of the problem.</div> <div><br></div> <div>Ron O.</div> <x-sigsep><pre>-- </pre></x-sigsep> <div><font face="Times New Roman" size="+1" color="#0000FF"><b>OVERS PIANOS - SYDNEY</b></font></div> <div><font color="#000000"><i>   </i></font><font color="#0000FF"><i>Grand Piano Manufacturers</i></font><font color="#000000"><br> _______________________</font></div> <div><font size="-2" color="#000000"><br> </font><font color="#000000">Web http://overspianos.com.au</font></div> <div><font color="#000000">mailto:info@overspianos.com.au<br> _______________________</font></div> </body> </html>