Jon, Ron, Del, Robert, Scott and list, Sorry for the delay in submitting this response to your interesting posts, last week was very hectic at our workshop, and then I contracted a virus which kept me horizontal over the weekend. Jon wrote; >If the keys are shorter in the treble, the balance rail is also set >at a corresponding angle. I realise that this is standard procedure with a shorter treble. >This will still provide a similar Key Ratio proportionally so a >different height heel would >not be needed necessarily. I've looked at this on paper following your post, and you could well be correct. I'll examine this further on CAD when I can, and report back to the list (hopefully with a jpeg of an action cross-section). >The bass and treble hammers (1 & 88) generally have weight >difference of 6 to 7 grams. >I don't see where the lighter treble hammers need the advantage of a >long keystick. Perhaps so, but similarly, I'm not sure that they must be shortened either. >To have the keys equal length on certain pianos would alter case >dimensions and overall >athetics with little or no performance benefit, seems to me. Certainly, but when designing a new instrument, it should be free issue for the case to be redesigned to suit revised aesthetics and/or for a particular tonal performance should it be desired. I'm not suggesting that it is wrong to use an angled strike, but I see no good reason why contemporary piano designers should 'run around like headless chickens' copying hundred year old designs without a justified reason for doing so. A parallel strike on the concert piano (with similar case dimensions) would allow for a reduction in sound board area behind the extreme treble bridge. This would very likely improve the tonal performance. Certainly, it would allow for an increase in sound board stiffness, for a given rib section modulus. >The problems I see are in the action setup on the production line. I >think that errors are >overlooked and the action designer's parameters are compromised for >the sake of production. Or complacency! >Generally by placing the capstan in what I consider a proper >attitude I have corrected >geometry/regulation maladies. The ideal capstan location I have >found is where the >capstan/cushion contact point at half-blow is renewed or maintained . > So on the production >line the capstan was installed at an incorrect angle and subsequent >regulation suffered. Agreed. If the plate positioning is erratic, there would be little hope of getting the action geometry set up correctly for each instrument on the assembly line. Ron N wrote; >[regarding the belly rail] >Functionally, it is part of the rim >to the soundboard and I tend to conceptually lump it in with the rest of >the rim. . . . . I like what you did with the 170 . . smooth >transitions tend to blend stresses over a broader area, and I'm all for >that. . . . . I'm curious about the damper wires going through >the belly rail though. I've wondered about doing that, but haven't yet >tried it. Neither have I. Thus far it's just a computer drawing. >Is the belly rail undercut far enough to clear the wires part way >down it's face, to keep from having to maintain wire clearance through the >full length of a 100mm hole and make the hole easier to bush? At this point, I intend to run the holes all the way to the lower edge of the belly rail. This design utilises a conventional damper guide assembly, complete with a standard damper guide rail. The damper lever wire-flange is located completely underneath the belly rail undercut. Yes, the drilling would need to be accurate and the drill sharp to prevent excessive wander. >If so, do you >lose enough stiffness there to kill some of the sustain the dampers were >necessary to contain in the first place? The wire clearance holes need not be too large. It therefore be a simple matter to size the sound board liner and belly rail to a suitable dimension, so as to maintain the required structural rigidity. Since the 170 plate and the damper guild rail holes will be CNC drilled, the system should function as intended, provided that the damper wire clearance holes and damper tray assembly are all set to XY coordinates, faithful the CAD drawings. >If not, how do you line everything >up and get the hole bushed? Just drilling a small diameter hole that deep >through maple, it's nearly impossible to control where it comes out at the >bottom. At least it has been for me. This came up a few times in years past >building player stacks and such, and I finally had to make spoon bits of >the appropriate diameter and length to control drift. This isn't a >criticism, you understand, just some of the thoughts I went through when I >considered doing this. > >Also, if I may, the soundboard problem (as opposed to the duplex problem) >in the killer octave is mostly too much flexibility already. Agreed, but I don't believe that a dog leg in the belly/sound board attachment (at the last damper) is the most appropriate way to build in the required stiffness here (as I am sure you and Scott Kuhn would agree). The belly (where it meets the active sound board panel) should be smoothly contoured if possible. If the sound board area is reduced on the opposite side of the bridge and/or the ribs increased in height, we would have at our disposal all of the means required to achieve whatever level of sound board rigidity we deem as appropriate. >Stiffer ribs, machine crowned, make a tremendous difference >over the panel supported flat ribbed compression crowned system in which >the killer octave is at it's worst. Getting the bridge as far away from the >belly rail and as near the center of the soundboard as possible, so it CAN >move, then stiffening the crowned ribs to both support string bearing and >control the movement (raising impedance and resonant frequency to slow >energy transfer and increase sustain), gets you most of the way there. I'm sure you're correct. I can hardly wait to build my own RC boards. Del wrote; > I would guess that most current production >concert grand pianos use this configuration simply because that is the way >the Steinway is configured and since most of them are essentially copies of >the D.. Exactly. Another recent example is Yamaha making an appearance with the Steinway 'Bell' in their recent CFs. I don't know how they don't feel embarrassed about blatantly copying this idea, especially since the benefits of the device, apart from 'sales spin', are probably marginal at best. >2) Equal Length Keys. I have rebuilt at least two concert grands that were >very similar to the D design with the exception that the bellyrails were >parallel to the front of the keybed and the keys were all of the same >length. In the two that I remember the overall performance was quite good >but the principle pianists complained about the 'feel' of the actions in the >treble section. In both cases there were complaints about repetition speed. >Now, I don't know if these complaints were legitimate-i.e., that repetition >was indeed a problem-or if it was simply that the feel was different than >what they were used to with the typical D-type actions. I think most pianists (and many techs) feel uncomfortable with anything that doesn't feel like a standard D. But it's time we moved forward from such a narrow view of piano standards. Talent and know how has never been concentrated with one company or individual - contrary to what you may have heard. >I must say, I have never cared for the longer key of the >Bosendorfer, but I'm not a pianist and am going strictly by tactile >feel. I do a lot more work >on D-type actions and it's not what I'm used to. Like most of the rest of us. >Yes, the C-88 hammer is »40% lighter than the A-1 hammer, but it still has >mass. Add to this the mass of the wippen assembly and it will be enough to >make the key bend. Clearly not as much as the bass hammers but some. As to >how much of a factor this is, I don't know. Something makes a difference. If the key is bending to any noticeable degree it is under engineered. Furthermore, if there is a perceived problem with the treble, what must be happening in the bass? >4) Key Inertia. I suspect this is more of a factor than anything else. If >repetition speed is a factor it is probably because of the increased inertia >that is inherent in the longer key. Maybe, but with an efficient action stack on a keyboard, I suspect that there would be nothing any long key length could do to slow repetition to any noticeable degree. >5) Action Geometry. Sorry, I can't really see this as being a particularly >important factor. Maybe, but I put this forward as a possible negative effect of an angled strike. >True, the capstan-to-heel contact point is not perfect, >but I doubt the difference can be felt in the real world. It is certainly >not enough of a factor to warrant the complexity of tapering the heel and >the consequent necessity of keeping the wippens is a specific order >throughout. Remember, you have to consider more than just the manufacture >of the instrument-someday it will have to be serviced as well. Additional >complexity is fine if there are substantial-even noticeable-performance >improvements. In this case, I doubt there would be. The level of piano technician competence has risen substantially in recent decades. Furthermore on forums such as this list, technical matters which previously were discussed only in factory circles, are regularly debated. For those who are interested, the information is there for the taking. While I agree that design complexity should be avoided where the benefits are marginal, we must nonetheless venture to 'make a change' before we can determine the benefits if any. My entire reason for questioning the use of an angled strike, was that I wondered if the complexity has any benefits which might justify its use. >6) Soundboard Area Behind the Bridge. This can be anything the >designer/builder wants it to be. If the designer has the courage to be different. >I don't think cost is the factor here. It is more tradition, fear and >self-imposed marketing constraints. "We've been doing it this way for over >a hundred years." Or, more to the point, "Steinway has been doing it this >way for over a hundred years, and when Steinway changes, then our R&D >department will discover that some new configuration really would have been >better all the time and then we'll change. Of course, if it turns out to >closely resemble the change Steinway just made, that will be pure >coincidence." Let's stop building pianos for traditional reasons. Marketing departments must be the antithesis of creativity. Unless we are prepared to allow the piano to evolve, it risks becoming commercially irrelevant like the harpsichord. We must move forward from the design thinking of 1900. >Finally, there is little marketing incentive to try something really new." >Check the four-colored glossies. At least as much dialog goes into >marketing tradition as anything else. When it comes to marketing hype, the 'tradition' word would have to be one of the most annoying and debilitating. >True, one company clearly >has had a problem with action geometry over the years, but this is due to >the assembly sequence and process, not the design. When the plate location >is made a variable, things get impossibly complicated. Of course, if they'd spent more effort on manufacturing the product, and less on marketing hype and stand over tactics, they might well have made better instruments. But then again, who really cares about quality anyhow? >10) Drilling Through the Soundboard/bellyrail. Yes, several piano builders >have used the technique of drilling through the bellyrail and soundboard for >damper wires. The several I have seen over the years had drilled through >the soundboard liner and not through the speaking portion of the board. Interesting, since I have never actually seen this on a piano yet. Our design also, has the clearance holes drilled through the liner only. Just shows that when you think you might have invented the wheel again, very often someone else has already 'been around the block and back' before you. There must be a lot of interesting domestic market pianos that were made in the states over the years, and never exported to the world market. >. . . . . Still, it is >not impossible to design for 72 dampers without the complexity of drilling >through the bellyrail. But you would be forced to limit reduce the sound board area between the bridge and the belly rail. Ron Overs Overs Pianos -- _________________________ Website: http://www.overspianos.com.au Email: mailto:ron@overspianos.com.au _________________________
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