To those commentators on piano design, and other interested lurkers, While it is generally accepted that the hammer strike line should be parallel to the front of the key bed for smaller grands, the situation is not so universally accepted for longer pianos. I have raised this issue with piano designers over the years and there is some variance of opinion. Obviously, a shortened treble layout will position the treble tuning pins closer to the tuner (this may certainly be an issue for a 3 metre piano), but is this the primary reason for shortening the treble end keys, and what are the negative outcomes of such a design regime? Recently, one designer claimed that shorter keys are necessary in the treble for the tone. He claimed that the resultant stiffer treble keys (of the angled strike-line pianos) assist with the feel of a 'crisp' treble. I remain a sceptic, since the hammer mass is less in the treble. Therefore the treble keys should appear to be relatively stiffer than those of the bass (even if they are of the same length and depth), since note C88 will be lifting a hammer which is often 40% lighter than the first bass hammer. Kawai, Fazioli, Steinway and Yamaha all shorten their treble end concert-piano key lengths (by as much as 75mm or 3"), while Bosendorfer persist with a non-angled strike in their 9'6" Imperial model. Certainly an angled-strike regime complicates the geometry setup for the wippen heels (most, if not all angled-strike adherents, seem not to make any adjustments). Ideally, when the strike is angled, the wippen heel depth should be greater for the shorter treble keys (if the contact between the capstan and heel is to remain on the fulcrum line at half dip). Therefore, if we are to produce wippens with idealised heel dimensions from bass to treble, for angled-strike-line pianos, the heels should vary in height from bass to treble accordingly. Such a heel set could be made from a specially tapered piece of stock prior to sawing them to width. When the strike line is parallel, no such geometry problems are encountered. While a parallel strike will place the treble tuning pins some distance away from the tuner (as already mentioned), the extreme treble is more likely to have a smaller sound board area between the bridge and the adjacent outer rim - a desirable design objective I would think. Some might consider using a greater dead-string-length between the capo bar and the tuning pins as a solution with the parallel-strike design, but excessive length here would surely encourage rendering and tuning stability problems. Your views I await. Ron O -- _________________________ Website: http://www.overspianos.com.au Email: mailto:ron@overspianos.com.au _________________________
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