This is a "repost", to give this thread another perspective:
Somewhere along the way piano manufacturers decided that aligning the grain of the soundboard at 90 degrees to the ribs produced "more", "louder" or "better" sound; this has become the industry standard. If you go back about a hundred or more years and look at antique pianos (I hope to write a PTJ article about this) you will find that many, if not most soundboards were made with ribs at another angle to the soundboard grain, often at 45 degrees.
At 45 degrees the different glued woods are better able to expand and contract across the fibers and the wood fibers are able to absorb the movement without cracking. In antique soundboards I have examined there are seldom cracks, whereas in more modern 90 degree glued soundboards cracks are common (note: this may be sampling bias as antiques with cracked soundboards may be more likely to have been discarded).
I have tested this by gluing two pieces of oak together at 45 degrees and using these in a wet-clamping application where the wood part was subjected to saturation and drying over a period of months. The wood remained completely glued and intact. Compare this to an old piece of plywood (usually with the grain at 90 degrees) and see how much separation you get.
If you made two soundboards in otherwise identical pianos with one with ribs at 90 degrees and one with ribs and grain at 45 degrees (the bridge is another issue) what difference in sound would you see? (note, this experiment would actually have to be repeated many times to support may conclusion; a test with two pianos would NOT be conclusive)
If this has been well discussed or tested I would love to know when and where!
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Blaine Hebert
Duarte CA
626-795-5170
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