What is "Tone Wood"?

The subject of "what is the best wood for..." keeps coming up here, so I thought I'd get a discussion going re. just what the properties are that make "tone wood" out of a timber. For the sake of discussion, I'm going to use the popular names, but I will post a list of the Latin names in a day or two. I'll also be talking about "real acoustic" instruments, not some of the inexpensive ones like all-birch Stellas or the more bling oriented acoustic electrics.

With violins, you have literally centuries of work by luthiers virtually defining the tone by use of spruce for the tops, maple for backs, sides, and necks, and ebony for fingerboards. With guitars, the range is a bit wider for tops with spruce, Western red cedar, mahogany, and redwood being used; for backs and sides, mahoganies and their ilk and various rosewoods have ruled, with cypress for Flamenco guitars, maple for archtops and some flattops, and more recently walnut, myrtle, and a whole range of alternatives coming on strong as the traditional wood become harder to get.

With ukes, it all starts with koa. Why? Simple...it was the most commonly available wood on the Hawaiian Islands, and it happens to be fairly close to mahogany in it's requisite properties. It's also beautiful.

So what are the properties that make certain woods appropriate for certain parts of the instruments?

Stability
Stiffness to weight ratio (aka Young's Modulus)
Resonant Q
Density (not the same as above...)
Ratio of cross grain stiffness to longitudinal stiffness
Toughness (resistance to breakage)
Tensile strength (not the same as stiffness)
Compression strength
Workability (related to toughness)
Ease of gluing (oily woods are difficult)
Ease of finishing
Availability
Cost

So the appropriateness of a wood is a recipe. You can't take any one or two of the above qualities and ignore the rest. All of the above qualities are quantifiable, too, and the US Agriculture Department has a fabulous Wood Handbook with a lot of the numbers and ratings. When you see the actual numbers, you start to see just why spruce makes sense, for instance.

More to follow, I'm sure...

Awesome idea! If I could add an additional question, can we clarify which factors are the ones that influence directly the sound of the instrument? My guess is:

stiffness to weight ratio
resonant Q (I believe this is a HUGE factor, but misunderstood or not commonly known)
Density
Ratio of cross grain stiffness to longitudinal stiffness
Tensile strength
compression strength

Rick, in this, could you touch base a little on things people do, and Luthiers might do that manipulate, in a good way, or bad a tone and/or resonance? Some like a pick gaurd, stickers, or other things on the top, which is my understanding can diminish the tone quality, or resonance. I see some with stickers all over the top, which kind of makes me wince, but to each their own. Another reason I am interested in this, is I have a mahogany concert, that is by far NOT an expensive instrument, but has a checkered board pattern carved in the entire top. For some reason, this specific uke has a much richer tone than others from the same builder, and has more sustain than any other uke I have played. It seems this uke just wants to ring out. If I am holding it, or just in the same room, talking and not touching the strings you can hear it hum & resonate. Kind of cool really IMHO. My theory is that it might have something to do with the pattern carved in the top maybe giving it more surface area? I think it was done more as a cosmetic thing, but by accident gave this uke a special sound. Maybe it was just a nice mistake that gives this uke it's tone, I don't know, but yourself in your wisdom would probably understand better than any of us.

I'm between spray coats right now with a trip to Carmel coming up, so I'll have to let questions pile up a bit, but one thing:

Do not confuse correlation with causality.

"I played this uke with a (fill in the blank) top and it was fantastic, therefore any uke made with that wood must be fantastic." NOT!
That's like "My kid ate carrots two days ago and got a cold today, therefore carrots cause the common cold." NOT!

At the end of the day, the luthier is the most important factor IMO. Choose wisely!

Thanks, Rick!

I'm not sure if you know, but your name comes up several times in the Ken Caillat's book "Making Rumours".

Looking forward to this thread. Thanks for starting it Rick.

I'm going to enjoy reading what people have to say about this. I have no experience in this. I do have one question though, who decides what good tone is? Is that subjective, or is there some measure?

Rllink said:

I'm going to enjoy reading what people have to say about this. I have no experience in this. I do have one question though, who decides what good tone is? Is that subjective, or is there some measure?

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It seems I like quoting and responding to you. Good questions.

The user of said instrument decides what is good tone. I like a rib eye, you a sirloin, my neighboir a porterhouse, we are all correct in the fact about what we like, all steaks but different. This is at its simplest level but if I like the sound of a Pono over a Koaloha who is to argue with me.

Now there are many factors that go into producing instruments with good tone and I appreciate that as much as the next guy. I have got some pretty expensive instruments in house and more on the way so I like to chase tone, as they say.. We can use words like sustain, projection, single note seperation etc. etc. But if you like the tone of what you are holding and playing that is the most important thing

Wood Handbook: Wood As An Engineering Material Centennial Edition U.S. Department Of Agriculture Forest Service

Ah a "Tale of Two DuDies", play nice guys.

I am interested in both the tonal aspects and what considerations luthiers give to the environmental conditions the instruments are subjected to, in the selection and handling of woods used in instrument making. Particularly:

Thermal Expansion and Contraction.
Moisture content
Humidity and temperature effects on Tone
Use of laminates and veneers
The effect of different woods on Sustain

I have an interest as well in wooden tone rims/rings and Burls, (relative to tone,sustain,volume), for the use in resonators of Banjoleles.

I will work around workabillity issues (such as cocobolo (oily) and narra "angry" grain) and cost issues (cheap or expensive) as long as it is stable and taps well (ie, good Q).

Stability is the first priority. If it taps well but has stability issues (ie- alot of Brazilian), it shouldn't get used.

Likewise, If a neck wood taps well but is "bendy" its "unstable". I can live with a stable (stiff, non bendy) neck wood that doesn't tap as nice as others (Hog and SC vs Narra) as long as (as rick has mentioned) it isn't super stiff/strong at the expense of dampening.

Traditional woods aren't necessarily the best- ie Ebony's stability issues for fingerboards against african blackwood , Koa's Q for ukes over, say, a rosewood for more modern uke playing.

Another few quickies:

"Tone" is not as all over the map as many would like to think. There can be and is some generalized agreement on good tone and bad tone. Yes, there are different qualities of tone that different folks may gravitate toward, but if you were to do some double blind testing, you'd be amazed at how consistent the results would be from beautiful tone to crappy. Yes, it may be subjective, but that does not preclude agreement, pushing the issue into a kind of cultural objectivity, if you will.

It takes playing a lot of instruments to start to understand this stuff, and I mean a lot. Hundreds. Thousands.

A luthier would rather work with great wood than bad wood, though there are a number of things we can do to compensate.

Lutherie wood is graded upon appearance. I've held AAAAA tops that had the stiffness of wet shirt cardboard. I've used seconds that sounded great.

Gardens_guitar, thanks for posting that link. Yeah, that's it.

Some players seem to be able to instantly find "the voice" of any quality of instrument and can seem to make a bad one sound good. Ry Cooder is one of the best of them. David Lindley is another.

Some players have their own true voice that comes through on any instrument they play. Some of it is about virtuosity, much is not. It's hard to pick out great tone players in the uke world; it's much easier in the guitar world. Think of five or six (OK, I'm pushing for seven!) guitarists, for instance, whom you can identify in five notes or less.

Ry Cooder
Sonny Landreth
Richard Thompson
Martin Simpson
Carlos Santana
Gabor Szabo
David Lindley

Would you folks elaborate on "Q" and "taps" please.

Q stands for Quality (there is a more technical term but it escapes me)

However, Wood with a good Q for a jazz archtop is totally different from what you would call good Q for a fingerstyle guitar, or uke. So there are different benchmarks - Judging a woods Q for both a Jazz guitar (maple) and fingerstyle guitar (rosewood) is like comparing Starwars with Good Will Hunting- they are both excellent but just different so the same parameters can't really be used against each other.

By tap I (not everyone) usually mean how good a wood rings- i want a long, clear note (brazilian, honduran and amazon RW, african blackwood (which is a rosewood), and Pernambuco have the best tap ive heard for my needs.

Beau Hannam Ukuleles said:

Q stands for Quality (there is a more technical term but it escapes me)

However, Wood with a good Q for a jazz archtop is totally different from what you would call good Q for a fingerstyle guitar, or uke.

By tap I (mot everyone) usually mean how good a wood rings- i want a long, clear note (brazilian, honduran and amazon RW, african blackwood (which is a rosewood), and Pernambuco have the best tap ive heard for my needs.

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I take it "Q" is a subjective thing?

Kayak Jim said:

I take it "Q" is a subjective thing?

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Well, a piece of brazilian RW that rings with an excellent Q will ring with an excellent Q for everyone (who can hear), as does a good piece of maple etc- But sometimes, a good long deep ring isn't what you want.

So I would say that:
Q is objective (the same for everyone),
The specific build's desired tone is the Subjective choice from Objective Q

Having said that, some people think only Blondes are beautiful and cant stand the sight of brunettes or redheads no matter how much they are universally acknowledged (objectively) as beautiful.

Beau your not helping here. You first suggested Qjazz is not the same as Quke. Then you say Q is objective. I realize you know what you mean but I don't.

When you defined tap is how the wood rings do you mean how well the wood sustains vibration with no strings or other wood attached?

I've seen Ash used for necks recently, (more than one citation). I would not characterize ash as bendy or as having a significant tap. I don't think it has much in the way of dampening characteristics either. I don't consider this a tone wood per se. It does have beneficial use in necks from a structural perspective. Is this your view as a luthier? (I'm an engineer).

nongdam said:

At the end of the day, the luthier is the most important factor IMO. Choose wisely!

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I almost never agree with Nongdam, but I do this time......