<!doctype html public "-//W3C//DTD W3 HTML//EN"> <html><head><style type="text/css"></style><title>Re: Designs on a grand scale</title></head><body> <div>Hi Alan and all,</div> <div><br></div> <blockquote type="cite" cite><font face="Arial">Ron Overs wrote;</font></blockquote> <blockquote type="cite" cite> </blockquote> <blockquote type="cite" cite><font face="Arial">"I look forward to the possibility that within 20 years a majority of pianos might use scales with deviations similar to the upright scale shown above, or better. With longer pianos it is possible to design a scale with even less tension deviation than the upright scale shown above."</font></blockquote> <blockquote type="cite" cite> </blockquote> <blockquote type="cite" cite><font face="Arial"><b>Just curious, for what size grand would this scale design be appropriate?</b></font></blockquote> <div><br></div> <div>This scale length would be most suitable for a grand of around 6' (183 cm). The longest speaking length in the bass is 133 cm, with a 150mm back scale. Some contemporary designers are using 140 cm for their 185 cm pianos A1 speaking length, but these instruments have a slightly restricted low bass, since there isn't room for a satisfactory back scale when this speaking length is used in such a short piano.</div> <div><br></div> <div>The lowest treble-bridge note on this scale would fit into a 157 cm grand, but the low bass would be too long. However, the scale could be adapted for a 157 cm instrument by shortening the lowest bass speaking length to around 116 - 118 cm and leaving the highest bass note at its original speaking length. This will preserve the smooth crossover between the treble and bass while using a shortened low bass which will fit in the case. A set of log style speaking lengths for the bass bridge can be derived using a multiplier factor of;</div> <div><br></div> <blockquote>*(L/l)^(1/(n-1))</blockquote> <div><br></div> <div>Where;</div> <blockquote><br></blockquote> <blockquote>L = the speaking length of the lowest bass note</blockquote> <blockquote>l = the speaking length of the highest bass note</blockquote> <blockquote>n - the number of notes in the bass section.</blockquote> <blockquote><br></blockquote> <div>So, lets say we've got a speaking length at A1 of 135 cm, just to use an industry standard for many 6' grands. Lets say the bass break note has a speaking length of 94 cm at note Bfl26  (eg. Yamaha G3).</div> <div><br></div> <div>Substituting the figures for the above speaking lengths into the above multiplier equation we get;</div> <div><br></div> <blockquote>=(135/94)^(1/(26-1))</blockquote> <blockquote>= 1.014584831</blockquote> <blockquote><br></blockquote> <div>You can now take this multiplier and create your log-style speaking lengths from Bfl26 to A1.</div> <div><br></div> <blockquote>Bfl26 = 94 cm</blockquote> <blockquote>A25 = 94 * 1.014584831  =  95.4  cm</blockquote> <blockquote>G#24 = 95.4 * 1.014584831 = 96.8 cm</blockquote> <blockquote>. . . etc. all  the way to A1 at 135 cm</blockquote> <blockquote><br></blockquote> <div>Scaling is a whole lot of fun once you learn to manipulate a spreadsheet.</div> <div><br></div> <div>However, I would never design a 6' piano with a break at note Bfl26. But I have used it as an example here, since it has been the default break point for many contemporary 6' grands.</div> <div><br></div> <blockquote type="cite" cite> <font face="Arial"><b>I've wondered why when over 100 years ago Steinway had a transition bridge design in their model (short) A was this abandoned.</b></font></blockquote> <div><br></div> <div>I know Alan, its incredible. Way back then, S&S were doing what a number of contemporary scale designers are now advocating, yet they gave it up. I don't believe the concept was abandoned because it didn't perform. I believe it had more to do with the cost of execution.</div> <div><br></div> <blockquote type="cite" cite><font face="Arial"><b> Has anyone ever contacted them to ask why or have they not employed scale designers since?</b></font></blockquote> <div><br></div> <div>I once asked Mr Max Mathias (former head of design for Steinway Hamburg) this question, but I didn't receive an answer which I felt I could believe. At the time (some time around 1988-89) Mr Mathias was visiting Sydney. I was showing him some images of a model M that I had rebuilt with a tenor bridge. He didn't seem to be impressed with my work at all. He said that Steinway used to do this sort of thing a hundred years ago, implying that I had lost my way by incorporating such an outdated idea into a modern grand piano design, which had sort of moved on from such 'archaic' practices. I remained unconvinced then and I remain unconvinced today. I believe that S&S were on the right track with their transition-bridged short A. These pianos respond very well to a remanufacture by changing the tr-ichord covered notes on the transition bridge so that they are all  bi-chord covered, and beefing up the soundboard ribs so that they can actually withstand the downbearing load under which they are placed. Oh, and the bass suspended bridge has to go, preferably with note A1 shortened back to 135 cm from its original 140 cm. Notice also that the short A, with the tenor bridge, breaks at D30 on the long bridge. This is a very intelligent place to break on a piano of such length. The later iterations, where all the bi-chord covers are mounted on the same long bridge, heading on down from C#29 to a F21/E20 cross, wouldn't hold a candle to the earlier concept.</div> <div><br></div> <div>I believe that whenever one encounters an instrument which has covered notes on the low end of the treble bridge, the proper factory-fix for these instruments is to redesign the plate and move the break up to include the wrapped notes in the bass section. In this way it becomes possible to incorporate a shortened speaking length for the first covered note, relative to the last plain wire. This is necessary to achieve a smooth scaling transition between the lowest plain strung notes and the first covered bi-chords. I realise that some makers use wrapped tri-chords when crossing from plains to covers, but this is also unnecessary, adding further inconvenience for the tuner with an increased risk of wild unisons. Its also a whole lot more trouble for the string winder. In short, it presents more trouble for everyone with no tangible gains that I can see.</div> <div><br></div> <div>Of course, redesigning a plate is beyond practicality for a rebuilder, but a tenor bridge will achieve the same outcome, and its doable. There are several on this list who have made the incorporation of a tenor bridge a routine procedure. The tenor-bridge-operation for the specialist grand rebuilder is the triple bypass for the specialist surgeon. Both have become routine, and both give new life to old hacks.</div> <div><br></div> <blockquote type="cite" cite> <font face="Arial"><b>And speaking of designs American, what on earth were they thinking of here?</b></font></blockquote> <blockquote type="cite" cite> </blockquote> <blockquote type="cite" cite><img src="cid:a0611040dc14a8fbbe71d@[192.168.0.4].1.0"></blockquote> <div><br></div> <div>Perhaps the designer was dreaming of space shuttles as he doodled with spatula and clay.</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:ron@overspianos.com.au<br> _______________________</font></div> </body> </html>