At 22:22 02/10/01 -0500, Ron Nossaman wrote: >You don't suppose???? So why would Yamaha compromise the stiffness of rim >laminations by (+-90°) cross plying layers? To what benefit, and at what >performance cost? I would have thought (and still do) that the structural >requirements of a bent rim would require nominally parallel grain amongst >the laminations to maximize stiffness. That is also what my intuition tells me, and yet quite a few makers, from Cristofori on (including quite recently Blüthner) have used an even greater proportion of vertical grain and not been averse to the use of softwood either. The question in my mind is just what degree of stiffness is necessary. Suppose we have 50/50 horizontal/vertical grain in a 50 mm inner rim, braced, and tightly glued to a 35 mm. outer rim, further made rigid by the attachment of the string plate, is the difference in impedance (I use the word loosely because I admit I could not define it tightly) between such a structure and a structure composed entirely of horizontal layers of maple, ash etc. going to be detectable even to scientific measuring methods, let alone to the bare ear? > ...I'll check it out and get back with either a raspberry, or some > flavor of despair. Despair that the great Yamaha, prince of the lyric arts, purveyor of pianofortes to the archangels has a soft rim???? From the sound of any Yamaha I've ever come across I wouldn't be surprised to discover a soundboard of glass fibre! JD PS. Wrote this before reading Del's reply.
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