So much fuss is made over tight grained spruce tops, The tighter the grain the more desirable for good tone, but I’d like to offer an alternative position…
back in the day, one of my jobs was to sort and grade guitar tops for different models in production, I would go through stacks and stacks of wood, only to make other stacks, piles and stashes. There were stacks for production guitars, custom guitars, high end guitars, and there was the S.T. pile.. The “Signin’ Tops”. Unlike tops with tight grain, the “Singin’ Tops” were graded to have between 10 and 12 grains per inch, and cut very well on the “Quarter.” That means the grain lines were perfectly perpendicular (90 degrees) to the surface of the top.
So what makes these tops better? Well you have to go back to the source of the guitar top to understand… Trees. Trees grow in annual cycles. Each cycle is made up of two different types of wood, early wood and late wood. Early wood grows faster in the spring and summer and the late wood grows much slower in the winter. Visually this dynamic duo makes up the look of the guitar tops…alternating light and dark lines. each pair makes up one year in the growth of the tree. You could count the dark lines on your top and you could figure out the age in years your instrument’s top.
It’s not just the G.P.I. (Grains Per Inch) that is important, but the cut that matters just as much, Spruce tops perform best and are most stable when they are perfectly quarter sawn. this means that the annual rings are oriented 90 degrees to surface of the top. Manufacturing tops this way makes them stiff. stiffness is a good thing when you have sever hundred pounds of force being exerted by the strings. it’s called “Cross Grain Stiffness.” You can tell how well a top is quartered by looking at its “Ray Fleck.” if a top is cut perfectly vertical, you will see lines the run perpendicular to the grains on the top. if the top is cut just a few degrees from vertical, the fleck disappears and the top will become soft and flexible. Cross grain stiffness make for a responsive top.
back to the Singin’ Top. these tops make the most of the light weight of the early wood, and the stiffness of the late wood. It’s a balance between response and stability. Too much late wood, and the top becomes dense and slow to react. too much early and the top becomes spongy and dead. in time and with some tutelage, I learned that the perfect signin’ top have 10 – 13 grains per inch, are straight and light in weight.
So what's the big deal you ask? the combination of a light top, and a stiff top, make for a more responsive top. Lighter (weight) tops respond when the strings are struck, and the stiffness makes for a outstanding projection and stability, it’s a Win Win!
I have found that these tops come around from time to time, they are manufactured somewhat by chance. you need to have just the right log, and just the right process. when then they both come together you get tops that are Tonally Awesome!