The majority of the red spruce that Martin buys is cut from long logs, rather than from split billets. That is because red spruce trees are small, and splitting the wood will reduce the yield. Splitting billets is also a lot more labor-intensive than cutting long logs with a sawmill. That said, Ted Davis always insisted on splitting the red spruce we cut, and I am convinced that it produces superior tonewood. Martin mentions the preference for tops cut from split billets in their specifications for topwood. Cutting long logs means that if the tree has spiral, then the tops will have runout. Most spruce trees grow with at least a little spiral. Moreover, the runout will be most severe on the bark edge, which is generally used as the joining edge because the heart of a red spruce has defects like pin knots and heart checks. Sawing spiral logs from split billets allows the cutter to determine the location that has zero runout. If you place the 'zero runout line' in the middle of each board, then you have minimized the total amount of runout. Each edge will have some runout, but in opposite directions. I have used this sawing technique for those billets with a lot of spiral (approaching 2" in two feet). But the ideal way to saw spiral billets is to place the zero runout line on the joining edge. That means that the tops still have runout, but it won't be seen because the top reflects the same in the middle. It also locates the stiffest, strongest wood under the bridge. I have noticed that there is a higher occurrence and degree of spiral in the slower-growing red spruce trees. Since Martin grades on tightness of grain, that would explain the increased incidence of runout in their higher grade red spruce tops. I am convinced that runout was one of the main factors Martin considered when they used red spruce in the 1930's. That is because many of those tops were reverse joined, with the bark edge on the outside. It is not possible to do that with much of the red spruce being cut today because the trees are smaller.

Hard to get a perfect set, almost every set will have some . Now lets all show the ones we've built with runout.
Tom

At what run-out angle do we start to see meaningful reductions in stiffness?

How little run-out is required to cause a noticeable difference in apparent brightness between the bass and treble sides of a spruce top?

If you're building to specific numbers top thickness wise then wouldn't a less stiff piece of wood sound better than a stiffer piece all else being equal?

If you're building to specific numbers top thickness wise then wouldn't a less stiff piece of wood sound better than a stiffer piece all else being equal?

That's what I mean. If you're building to specific thickness a less stiff top would move more readily with string vibration?