Hi Ron, I'm far from being a piano designer, but since lack of qualification seldom prevents speculation on my part, I'll offer some possibles. As far as action response, perhaps that "crispness" in the treble could be little more than the geometry inefficiencies resulting from the shorter keys and wippen heel/capstan intersection height offsetting the lessened inertial mass of the hammer/shank somewhat. Making it too efficient may make it feel too "easy" in the top end. Just a thought. Past a certain point, it gets tough to determine what causes what in tactile perception. Top and bottom plates would certainly help control key flex in these longer keys, but I'd wonder that there isn't a considerable difference in feel resulting in different proportions of mass between the keys and action parts. For instance, given similar UW and DW, would a lightly weighted treble hammer on a long key feel different than a light hammer with weighted long key, or a shorter key with compromised wippen/capstan contact height, or a shorter key with optimal W/C with weighted hammer or key? There are a whole lot of different combinations in varying proportional degrees that would probably map into a fairly broad perceptual curve if everything was tried systematically and put together in a cause and effect chart of sorts. I know a lot of this kind of thing has already been done, but I don't know how exhaustive the experimentation was, or how one would find the information. I can't imagine a designer giving even a passing thought to whether it's easier to reach tuning pins or not. He'll probably be having enough troubles trying to fit a minimally compromised instrument into the manufacturer's outlined box. I don't like the increased tuning pin to counter bearing idea much either, for the reasons you mentioned. Acoustically, yes, I think there's too much soundboard behind the treble bridge too. That should be realistically within the designer's area of choice unless he's working within a manufacturer's existing rim press and/or plate pattern limitations. I do think I can make a case for the belly bar dog leg in the treble though. It's to get the bridge footprint as far away from the rim as possible within the limitations of the hammer placement, determined by the V bar and strike point. That's also why treble bridges are undercut, or beveled along the front of the last couple of octaves. The bridge/V bar/strike point are in a fixed relationship (theoretically), and the belly bar position is determined in the design phase to accommodate them. Down scale a little, it jags back to allow clearance for the dampers, even though that moves the rim closer to the bridge, it's a less critical difference because the bridge is far enough away by then that it's doesn't cause a big change in flexibility. I suspect that's a problem Del has dealt with extensively in getting dampers far enough up scale to damp the long sustain trebles in his designs. Bringing the strike line forward in the treble will bring the whole belly bar closer to the bridge everywhere but C-8. It's probably not enough to make any real difference in practice but it does do that. What's it all mean? I don't have anything like nearly enough information to draw lines, but I can still speculate. Like you, I'll take any information and clarification anyone has to offer. Ron N
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