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Acoustic Soundboard: Grading Tonewoods—Tops

Acoustic Soundboard: Grading Tonewoods—Tops
A deflection jig is used to accurately measure the stiffness and deflection of each top at the Huss & Dalton shop.

Beauty is only skin deep when it comes to choosing the right tonewoods for your dream guitar.

For our customers, the selection and grading of tonewoods can be one of the most confusing aspects of ordering a custom guitar. The end user is often involved in the selection of woods for their dream creation from one-man shops and small-production outfits like ours, and this can be a good or a bad thing. It all depends on how much you know about guitar woods and how insistent you are that you make the selections. At Huss & Dalton, we don’t sell direct to customers, but we do allow people to come to the shop and select upgraded woods.

When it comes to woods and their grade, at some point our industry adopted the ubiquitous “A” grading system. Consumers of high-end guitars often use the terminology, but honestly, it’s seldom used by builders. The main reason for this is twofold: For one, every wood dealer has his/her own version of how many “As” to attach to a particular set of woods.

One dealer’s AAA might qualify as another dealer’s AAAA, or an even higher grade. This way of talking about woods is so bastardized now that it’s virtually meaningless.

The other reason that builders don’t often use this grading system is because we almost always buy wood from known suppliers we’ve worked with for many years. They know what we like, what we don’t like, and rarely ever send us anything that isn’t a good fit.

Grading top woods is the most important and likely the least understood part of the wood-selection process. In hopes of giving you a better understanding of what makes for a good top, the following criteria is what we follow for the most part when grading top woods.

This way of talking about woods is so bastardized now that it’s virtually meaningless.

Quarter sawn. This essentially means that the grain in the top runs perpendicular to the top surface as close to 90 percent as possible. This is crucial for stiffness.

Runout. This is the strange phenomenon that makes the top look like it’s two different colors depending on which direction you view it from. It’s usually caused by the tree being smaller in diameter—commonly seen on species such as Engelmann and red spruce—and with a slight twist as the log goes upwards. Runout is a wee bit important structurally, but not really a deal breaker. Most people simply just don’t like the way it looks, so we avoid it as much as possible. If it’s very important for you to not see any runout, let your builder know and stay away from the species in which it’s most common.

Grain tightness. This is really only important in terms of cosmetics. Some of the Holy Grail guitars from pre-World War II actually have very wide grain patterns because much of the supply of Appalachian red spruce was used up to make airplane propellers for the war. Yet, they are still amongst the best-sounding guitars ever made.

Stiffness. We use a deflection jig (Photo 1) here at Huss & Dalton to measure stiffness. If a top is not stiff enough, it fails the test and isn’t used. Stiffness is very important to both the tone and longevity of a guitar.

Color. It’s the least important grading variable for us, yet it’s still the one that many use most often to judge a top. We know how seldom facial beauty works as a guide when choosing a mate in life, so the same applies here.

Tap tone. I may get into some real trouble for this opinion, but I’ve never been able to make sense of tap tone as a way to judge a top. I tried very early in my career to make it work for us, but there seemed to be too many variables and human-error opportunities for this to be a good judge of a top. I will not say that it doesn’t work for others. It just doesn’t work for me because I find it to be a very unscientific and unquantifiable practice.

When I decided that the tap-tone method didn’t work for me, I developed the deflection jig as a way to judge stiffness with and against the grain, and to get a consistent tone (which comes along with this test). I thought I was pretty smart until I read there were some classical builders back in the day that used a can of beans for weight and a cabinet scraper in place of a thickness sander to achieve the same result around 100 years ago!

In the end, my advice is to listen to your luthier when choosing woods for your dream instrument. It starts with the top and it’s in your builder’s best interest to get you the best top possible.