---------------------- multipart/alternative attachment Hello Ron O. Nice post and a fine addition to the topical side of this thread. Muchly appreciated from this reader. A couple of comments below for your edification. Overs Pianos wrote: > Folks, Having just completed two months of testing sound board test > strips, ie. one rib mounted to a strip of sound board (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), I find the debate on this thread to be a bit > frustrating. 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 > (which perhaps could be better named the 'collapsed sound board > section') 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. As I understand it this is Fenners observation as well. Yet he will have it that all pianos have this weak spot and the potential for it having an accute and ofte times experienced as negative influence on the sound. > 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 > (and would commend the practice to others who feel compelled put > forward an argument). 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. Here is where we are bound to part ways. I find it impossible to not accept a manufactures designs and techniques legitimate when they have resulted in such a dominant position for so very very long. That does not mean that I believe that there are not other ways of building fine instruments.. (as witnessed by my recent enthusiastic reports on the Stuart piano) It just means that I accept that there are several acceptable ways of skinning the proverbial cat as it were. > 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. We still have never really managed a cool discussion about whether or not a CC board and a RC board can really be made to have identical ( or nearly so ) sound qualities. That being said.. I agree that both can provide very fine sound. And I appreciate your confirmation about absolute character of the claim on the part of those adhering to this veiw of soundboard design relative to failure question. Indeed... if that were not claimed... the whole point made in favour RC boards would be seriously undermined. > 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. I do not think that anyone has denied that any particular piano can suffer any particular failure at that stage of its journey. Certainly that was not my intention. I have simply pointed out that the degree and frequency of the problems claimed found in CC boards is at astounding odds with the popular acceptance of these instruments. Far to much so for me to ignore. This leads me to conclude that 1:) Either the market place is totally bonkers, ( to a degree that makes the word absurd seem absurd) or 2:) There is either something directly wrong with the claims against the CC board (and reasoning behind it) or 3) The <<problem>> is simply overstated in degree. Thanks to both you and Del for your fine responses to this thought. My own trail to greater understanding lies mostly ahead thanks in no small part to the both of you. > Ron O. Cheers RicB -- Richard Brekne RPT, N.P.T.F. UiB, Bergen, Norway mailto:rbrekne@broadpark.no http://home.broadpark.no/~rbrekne/ricmain.html http://www.hf.uib.no/grieg/personer/cv_RB.html ---------------------- multipart/alternative attachment An HTML attachment was scrubbed... URL: https://www.moypiano.com/ptg/pianotech.php/attachments/e3/24/b0/06/attachment.htm ---------------------- multipart/alternative attachment--
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