Brian Roger and list, Brian the first respondent wrote; >It comes to my mind that perhaps the reasons for the angling of the hammer >line might have come from trying to design what they thought was a good >belly (string scale, bridge location / layout, etc.) as they might have been >thinking 100 years ago. It would tend to give some more room up there in >the top end to fan those strings off to the right a bit, especially if they >were concerned with a rear duplex scale. And yet, while the stike line is pulled back in the treble, the speaking lengths often are substantially perpendicular to the stretcher rail for the top string section. In these instances the speaking lengths run at an angle (anticlockwise) relative to the hammer shank for all of the treble sections. >Action geometry was probably more >of an afterthought. Absolutely! It always amazes me when assessing grands for a rebuild, just what a mess many manufacturers get into when they set up the action. With so much geometry variability from piano to piano it's little wonder that many are ordinary to play. Several commentators on this list have referred to the practice of a certain maker, where the capstans were (and possibly still are) positioned on the key to place it under the wippen heel, after the action stack is positioned on the key frame to get the strike more or less correct relative to the plate position. I cannot understand how such ordinary assembly standards can be tolerated. It must inevitably lead to variable touch uniformity from one piano to another (a 2 mm variation to the capstan position makes a substantial difference to the hammer/key ratio). An angled strike line makes the process of firstly designing the action geometry, and secondly building it faithful to the working drawings, all the more difficult. I have noticed that the wippen heel depths are not, in practice, varied to satisfy the geometry requirements from the bass to the treble of angled-strike pianos. This further compromises the performance of these actions. Often it seems, makers of concert pianos with angled strikes will set the wippen heels more or less to satisfy the requirements for the treble. When bass end heels are of the same dimension, we find that the capstan/heel contact is below the fulcrum line at half dip. This is not good since the notes with the heaviest hammers are those which can least afford to have compromised action geometry. I have considered custom machining a set of wippen heels to satisfy the geometry requirements of an angled-strike concert piano (wippens thus modified would need to be kept in their proper order from bass to treble). Ideas for improvement always seem to outstrip the available time for execution. >That being said, I think you are much more correct in thinking that a >smaller area between the bridge and the outer rim area is a more desirable >design, functionally speaking. Maybe. I tend to worry about phase problems which might occur when a travelling energy wave moves away from both sides of the bridge to meet the outer rim and the belly rail. I can't help thinking that this must contribute to an increase in tonal distortion when the two (out of phase) reflected energy waves meet the bridge again. When Samuel Wolfenden built prototype upright pianos during the earlier part of last century, he made bellies which extended upwards from the treble bridge right up behind the pin block, in an attempt to equalise the sound board area on either side of the treble bridge. Strangely, he found there was little benefit to be gained (of course he might better have reduced the area under the bridge as the Fandrich Bros did). Nevertheless, when starting new designs with a clean computer screen, factors such as the sound board area adjacent to each bridge section might sensibly be allowed to have some influence. >I suspect that the angled hammer line is one of those 'design features' >that's a holdover from the "that's the way it's always been done, so that's >the way we build 'em" era. Unfortunately we seem to be still in it. Lets say 'to hell' with 'the way it's always been done'. Let's start over with a clean computer screen now and again, to see where it might take us. >And another thing that came to mind... How >often is a piano actually _designed_ to be easier for the tuner to tune? >Sounds more like marketing to me. Maybe, but tuners might evolve with longer arms if they only tuned 3 metre pianos with parallel strike lines. >Just some random thoughts from the peanut gallery. Peanut galleries can be interesting places where the creative spirit thrives. Then Roger wrote; >One variable you omitted, inertia is also being reduced as you move up the >scale since the hammers are smaller and the key weights are being moved >back. How much effect does this have with regards to perception, feel, and >actual action saturation? Absolutely! Inertia, friction, changing leverage ratio during the execution of the key stroke, and stiffness must all combine in a manner which is not completely understood, to influence our subjective assessment of touch. >So many of todays pianos have soft wood frames, bedding is very critical >in the treble, for both tone and feel. Yamaha concert grands need bedding >each time you tune them, for optimum performance. This modern idea of floppy key frames and floppy (light) plates doesn't do much to enhance the performance (manufacturer's balance sheet excepted). >Most concert grands have reduced treble shank mass, for tonal reasons. >Adding to the balance problem. Hear here! Has anyone out there done AB testing of tapered shanks against standard hex? >Good quality maple shoes can negate the effect of key whip lash, and lower >saturation. Would you please expand on the above for me? Thanks - I am probably suffering from terminology deficiency. >Like you I'm skeptical about the idea of shortening the key for >stiffness reasons. >How much is deep rooted tradition, and how much is science? Good question. >I suspect that once the scale is set and the plate is cast, make it work >enters the picture. I am particularly interested in this since I suspect that the angled strike creates many construction problems (the Overs-Steinbach grand which we are making now - using a Samick case and plate - has a parallel stike). However, parallel strike concert pianos look a bit strange to my 'eye' (perhaps experience develops prejudice). I have used a parallel strike for our own 170 cm grand, scheduled for prototyping next August, but the 295 cm concert piano I have on computer currently has an angled strike of minus 3.4 degrees. This design is nowhere near complete, but I wonder about the wisdom of persisting with the angled strike when it is so much extra trouble. When you look at Steinway Ds its no wonder they're difficult to make. The key bed front is at greater than 90 degrees with respect to the long side and the strike is angled. There's barely a square line anywhere on the piano. >Brian has a good point about the belly rail. Start messing with it, now we >need to look at under levers etc. >Now, is the dog leg in the leading edge of the board/belly rail, there to >accommodate the treble strike point, or the bass strike point. Isn't it there basically to accommodate the damper wires. I presume that you are referring to the dog leg in the belly rail where the dampers end, normally around F#70. This section of the board immediately before the end of the dampers is significantly reduced in surface area between the belly rail and bridge. I have had this in mind, as the number one suspect, as a causal agent of the 'killer octave' so frequently mentioned on this list. Earlier in this post I mentioned the phase problems which might occur when the bridge is not located in the center of the board. The 'dog leg' may cause similar phase problems, as a result of its non-uniform distance from the bridge. >How many >empirical experiments were conducted to arrive at this configuration? As >an aside, I have noted that many cracked boards, start to crack at the >corner of the dog leg. And what an interesting aside, since it is possible that the board might be quite stressed at this location, mechanically as well as acoustically. Our 170 cm grand design has a uniform transition at the location of the 'dog leg', which runs directly into the sound board cut-off rail. The belly comes in quite close to the damper wires with a minimal width of sound board contact with the belly rail. The break is at F#58/G59 (this piano has three string sections only). There are 15 dampers in the top treble section finishing at note A73 (the 73 dampers is a response to our fantastic SD-10 Baldwin - 1980 rebuild, which really requires more dampers since it has incredible treble sustain - we are planning to build our 170 as a long-tone piano). The top section damper wires pass through clearance holes drilled into the belly rail sound board contact area (I believe this has been done before, though I have not seen any examples. Does anyone out there know of a piano with this feature?). A plan drawing of our 170 treble can be seen at; http://www.overspianos.com.au/170tr.jpeg This drawing shows some layers only, since I must keep some of my 'powder dry' (this piano will not be available for sale until 2002 at the earliest). Where are you Del? I just got Ron N's contribution, but I need to read it yet before being able to respond. Regards to all. Ron O. -- Overs Pianos Sydney Australia ________________________ Web site: http://www.overspianos.com.au Email: mailto:ron@overspianos.com.au ________________________
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