---------------------- multipart/related attachment --============_-1160819086==_ma============ >At 11:40 AM +0200 26/4/03, antares@euronet.nl wrote: >I have been in this business for some time and I have never - really >- understood the workings of the cut off bar. Ideally, a piano should (all other things being equal) produce a superior tone if the long bridge is positioned at the center of the sound board. Of course, it is impossible to arrange for the bridge to be located perfectly thus, but an appropriately designed cut-off will help it follow this idealised situation more faithfully. While it is possible to produce an instrument with a most satisfactory tone, which nonetheless does not conform to this so-called 'ideal' of piano making, such an instrument may still have sounded a little cleaner and more controlled if it had a cut-off, allowing the long bridge to be more favorably positioned. Take a look at the following jpeg outline of a concert grand which I am designing at present. =46or those who's email programme can't display the above image, I've uploaded it to; http://overspianos.com.au/newslt.dec.02.jpg (the image will be available for a couple of days. Please view it with your web browser). BTW, for those who were posting about log-style scales, the above long bridge conforms to a log-style design. Just digressing for a moment - that grand piano that you mentioned recently Bob I (when I was deeply immersed in sound-board-rib land) is crying out for a log-style scale down to D30, then a tenor with covered bichords from C#29 down to F21 (a silly place to cross in a 185 cm piano), with the complete removal of that suspended bass bridge. If the front duplexes are anything like the Hamburg alternative they will be screamingly noisy - definitely a de-tune required here - this means you get to play with your angle grinder. I've had local enquiries for rebuilding of this model which I've turned down on account of the unbelievable number of design problems which the instrument presents - its just too hard to make a buck with all the changes that are required. I've rebuilt three of them, and now would prefer to 'run for cover'. I can't understand how these builders persist with that model and continue to take themselves seriously. Nevertherless, it is possible to make it into something, as long as your prepared to ditch practically everything OEM. (and now its back to the subject at hand, which doesn't have a lot to do with hammers or rebuilding as such) The RH piano image illustrates a case fitted with a typical small angled cut-off, which achieves little more than to provide a talking-point for the salesman's further boredom of the punters. The LH image shows just how an effective cut-off design can disable the unwanted distortion-promoting bass corner of the sound board. Corners make very poor shapes from an acoustical perspective. The curved cut-off will do much to eliminate the unwanted bass corner and to allow for the otherwise overly-long ribs, which span the board to the bass corner, to be shortened. Big sound boards do not necessarily produce big tone. The piano with the biggest sound board on the planet has a serious dynamic problem which is well known to students of piano design. Our future production pianos will not only have a curved laminated cut-off, but the bass corner area behind the cut-off will be filled with a structural plywood fill-in, which will be veneered with the same veneer as the inner surface of the outer rim. I can't see the sense in wasting valuable belly wood, for the sole purpose of blocking an unwanted hole. Much better to use 19 mm ply in its place, which will further enhance the lateral rigidity of the cut-off system. The saving in belly wood can be considerable in the case of a concert piano such as the one illustrated above. Also notice that the sound board with the real cut-off resembles a 'bent tear-drop' shape. This board will conform to that other ideal of a reducing sound board area from the bass to the high treble. > What I do remember however is the older Uebel & Lechleiter uprights >without cut off bar, that sounded impressively nice, with the >emphasis on mellowness and lower partial characteristics. The old Ubels were indeed a fine sounding instrument, and proof that it is possible to build a nice sounding piano that is a bit 'rough at the edges'. They even had the good sense to place the break at D30/D#31, which was reasonably forward thinking for 1900. Some of the contemporary commercial manufacturers might well benefit from looking over a Ubel and pondering over these musically satisfying but economical creations. You never know, the production of a pleasant sounding cheaper instrument might even prove to be a new talking point on the sales floor, or am I being a bit old fashioned? Ron O. Now Andr=E9, I've had enough of this - thanks anyhow! Its 2.40 am here in Sydney, so I'm going to get horizontal for a while. -- _______________________ OVERS PIANOS - SYDNEY Grand Piano Manufacturers Web: http://overspianos.com.au mailto:info@overspianos.com.au _______________________ --============_-1160819086==_ma============ An HTML attachment was scrubbed... URL: https://www.moypiano.com/ptg/pianotech.php/attachments/67/62/ca/12/attachment.htm --============_-1160819086==_ma============-- ---------------------- multipart/related attachment A non-text attachment was scrubbed... Name: newslt.dec.02.jpg Type: image/jpeg Size: 35928 bytes Desc: not available Url : https://www.moypiano.com/ptg/pianotech.php/attachments/69/ab/c1/7d/newslt.dec.02.jpg ---------------------- multipart/related attachment--
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