Thoughts on spruce

I’ve been thinking about spruce a lot recently. The soundboard is perhaps the single most important piece of wood in the whole guitar. It’s hard to quantify how I judge a top. There’s the ephemeral, wispy sound I listen for as I run my fingers over it, the different tap tones when held at different nodes, how exactly I find those nodes in a raw piece… Visually, however, there’s a lot that can be explained more readily. When discussing fine Adirondack spruce, a number of factors come to mind.

For one, not all red spruce (picea rubensis) can rightly be called Adirondack. Only logs harvested at a certain altitude along the Adirondack range hold this title. This helps contribute to their unique grain structure. This is the reason I order everything through Old Standard Wood.

When Old Standard grades a top, they do so based on grain lines per inch, color, straightness of the grain, how perfectly the piece is quarterered, and the presence of any darker “winter” grain.

Certain companies favor certain attributes in the tops they select. I’ve been told Collings selects tops mainly based on homogenous color, with grain count and degree quartersawn as secondary considerations.

I like to select tops based on the model guitar I’m building. A rosewood guitar would have a slightly higher grade top, maybe a AAA versus a AAAA. The main factor I usually ask for is degree quartersawn, which is often visually manifest as cross grain silk patterns. It makes for a stiffer top, which goes well with the ’30s brace pattern (an inherently flexible design).

To me, some winter grain is not undesireable at all. It presents no structural considerations. I also like tops that have slightly wider grain at the margins. This loosens up the tangential stiffness just a bit towards the outer edges of the lower bout. If you imagine a scallop pattern, this is something we want to achieve. It’s akin to the flexible membrane surrounding a speaker cone, allowing the center portion to flex and move freely.

Bearclaw, while not as common in Adirondack as in other spruces, can be quite interesting. The little ripples in the grain that form the bearclaw pattern, depending on where they are located, can give the top tonal color, because after all, they signify a change in the overall stiffness of the piece. It’s a double edged sword having changes in stiffness, however. It adds a new variable to the tonal equation.This makes bearclawed tops a little less reliable. I have, however, built some incredible guitars with bearclaw Adirondack, and it certainly is visually striking.

Its amazing the variability from one piece to the next. The whims of mother nature, plus the keen eye of the sawyer, give me so many different colors on my tonal palette.

 

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