Cedar vs Adirondack Spruce

[Carey]

WRC is sometimes described as "warm-sounding", maybe because of its upper-bass and lower-midrange tendencies; but what I mainly hear from it is edginess in the trebles that's pleasing at first, but grates and is fatiguing over time.

[Racerbob]

On of the most sweet guitars I had surprised me when I tried it. It was a 12 fret deep body OOO SCGC with an adi top and koa b&s. I would have never guessed that combination would have that tone and lots of head room.

The builder is critical.

[Alan Carruth]

jt1 wrote:
"Really? Opposite ends of the steel-string guitar spectrum."

In a production guitar, on average, yes. On average Red ('Adirondack') spruce tends to be denser than most, while WRC is lowest in density of the usual top woods on average. If the factory is building to those averages their Red spruce tops will be heavier than their WRC ones most of the time and the spruce ones will have more 'headroom' while the WRC ones will be more 'responsive'.

An individual maker can pick the top to suit the sound the customer wants, and there's enough overlap in the properties of the various woods that it's usually possible to find one of most species that can be made to give the desired sound. Of course, most makers can also vary things like the box depth, sound hole size, and bracing, to shift things in the desired direction as well.

"The race is not always to the swift, nor the battle to the strong, but that's where the smart money goes". It's usually easier to make a guitar with good head room if you use Sitka or Red spruce; most of the tops in your stash will more or less do the trick. You might have to search a while to find a cedar top that will be as good. If the customer wants the 'cedar' sound with headroom, I'd try to talk then into redwood, which tends to be more in the same class for density and hardness with spruce, but has cedar's low damping. The more you 'go with the flow' the easier it will be to get what you want.

[jt1]

Originally Posted by Alan Carruth

In a production guitar, on average, yes. On average Red ('Adirondack') spruce tends to be denser than most, while WRC is lowest in density of the usual top woods on average. If the factory is building to those averages their Red spruce tops will be heavier than their WRC ones most of the time and the spruce ones will have more 'headroom' while the WRC ones will be more 'responsive'.

But this presumes that the factory builds to the same "average" regardless of the species of top wood, right? What factory uses the same thickness red spruce and cedar tops?

[Jwills57]

What Alan Carruth said is exactly true, in my experience. In a factory setting there's a pile of 100 cedar tops, which have probably already passed some modicum of cosmetic inspection, and a guy/gal just grabs one for the next guitar and that's how it works until the pile is gone. Same with spruce. But if you're commissioning a guitar from a luthier, he/she can really search to find you the best top. Not all spruce tops are of equal value and the same is true for cedar tops. I've commissioned several guitars over the years built with cedar tops, and I always instructed the luthier to select a cedar top which had the best combination of stiffness and tap tone. I had one luthier tell me he sampled over 200 tops until he found one that he thought would do. I think the guitars I've had built with cedar tops are truly exceptional instruments, very warm and dynamic and loud. So, I actually love a good cedar-top instrument. There's a rap that cedar-topped guitars don't hold up to heavier playing with a pick but I don't know if I actually believe that; just because it's not customary doesn't mean it's not effective. I never had to work very hard to get a big, blooming, dynamic sound out of a cedar-topped guitar. I sometimes wonder if players playing with an aggressive pick attack are just playing cedar-topped guitars too hard. Anyway, that's my two-cents worth.

[Guitars44me]

"The race is not always to the swift, nor the battle to the strong, but that's where the smart money goes".

So true, Alan! I LOVE this! Hahaha

And, JK has now built me three FINE CANNONS with Cedar tops. Mahogany, Maple, and Spanish Cedar (Mahogany relative) backs and sides. All three sound spectacular, as do his with Adi and Euro spruce I have owned.

My smart money is going to the next JK in Super Cedar over old reclaimed beam Brazilian Rosewood....

Salud

Paul

[Alan Carruth]

I should have been clearer. If the factory is using those averages, as they must, to determine the 'proper' thickness for each species, then the WRC tops will be thicker then the Red spruce for any given design, but the cedar tops will still be lighter on average.

This is due to the fact that the Young's modulus along the grain, which determines the stiffness at a given thickness, tracks the density quite well, and follows the same rule for all softwoods. The relationship there is close to linear; as the density rises so does the Young's modulus along the grain. However, bending stiffness goes as the cube of thickness: twice as thick is eight times as stiff of the Young's modulus is the same, and 25% thicker gives about twice the stiffness.

Cross grain stiffness is pretty much a function of how well quartered the top is, and drops off fast when the ring lines go a little bit off perpendicular. If you plot the long grain Young's modulus against density most of the points fall close to the same line: about 60% are within 10% plus or minus. If you do the same for cross grain stiffness, you get almost a perfect scatter: there's no discernible relationship. Cross stiffness is acoustically important to some degree, but does not seem to help much structurally, and is enough lower than long grain stiffness that it can usually be ignored in determining how thick to make the top. That's a good thing, given how variable it is.

If you have two pieces of wood, and the Red spruce is 50% denser than the WRC, the spruce will have a Young's modulus that's about twice as high. The WRC top only needs to be made 25% thicker to get up to the same stiffness, not the 50% thicker that would make them weigh the same, and should end up about 20% lighter. Most of the weight of the top is the top itself; bracing might account for about 30% of the total, and could easily be the same in both tops. so there's still a weight saving.

I'll note that when headroom is desired makers often use wood that has prominent late wood lines. The late wood adds stiffness along the grain, but it also adds weight even faster, so that sort of wood can be made thinner, but ends up weighing more at a given stiffness. The added mass helps to give the top the 'resistance' that it needs to have lots of headroom, but, again, it also cuts down on 'responsiveness'. 'Horses for courses' as the Brits say.

The bridge, and brace profile, can also be used to fine tune these things. And there is a lot of variation within each species, so, again, an individual maker can pick and choose and find wood of most species that will work to produce the desired sound. You don't seem many cedar topped guitars that were designed and built for 'headroom' for the same reason you don't see many Red spruce topped guitars that were built for 'responsiveness': it's easier to go with what works naturally. But it can be done.

See why I used the shorthand version?

[Tony Burns]

IMO , its not just the wood combinations but the actual piece of wood -
not every piece of either wood is perfect together -What matters the most is what the luthier can do with the wood -grade, age etc.
Id ask the luthier about his/her experience with wood combinations etc.
Ask them which one would get the sound you want- they might have another combination youve never thought about .
My favorite is Brazilian with Red spruce ( adirondack )
but i also own a stellar guitar made of EIR and a fancy Sitka spruce bear claw - but its 12 fret big body dynamo banjo killer -
both different but both are stellar. depends on the day -which one i love the most.

[jt1]

Originally Posted by Alan Carruth

I should have been clearer. If the factory is using those averages, as they must, to determine the 'proper' thickness for each species, then the WRC tops will be thicker then the Red spruce for any given design, but the cedar tops will still be lighter on average.

Thanks! This makes much more sense. Though given the differences in density, I'd like data before I'd agree that the "WRC tops will be thicker then [than] the Red spruce for any given design, but the cedar tops will still be lighter on average

Lighter, even though thicker? Numbers, please.

[mikealpine]

I've got a Cedar/Rosewood Furch dread that is plenty loud, and has a warm-but-crisp tone that fits well with other players. Maybe it isn't bluegrass-loud but for anything else I want to throw at it, seems to do just fine. As has been stated, though, you need to ask your builder what they are comfortable with. I also thought that redwood might be a better fit, but each builder should know what they can and can't get from their models. Good luck!

[Alan Carruth]

jt1 asked:
"Lighter, even though thicker? Numbers, please."

OK.

A more or less normal density for WRC is around 360 kg/m^3, and Red spruce tends to run around 480. If you like you can stick in a decimal point to get specific gravity (.36 and .48) and taking the density of water as about 62.5 lb/ft^3 you get 22.5 #/ft^3 and 30 #/ft^3. Any particular piece could be plus or minus 20% from those numbers, or even more. I use metric measures in my work.

If those two pieces are typical in terms of the way the Young's modulus along the grain (Elong) relates to the density, then the cedar will have an Elong value of about 8600 megaPascals, and the spruce will be around 14,000 mPa. The formula I use to calculate the thickness of the top based on these numbers and a desired stiffness gives a thickness for the cedar top of just over 3 mm; .125". The spruce top comes in at 2.6 mm, just over .102".

Multiply the density of the wood times the thickness for each, and you find that the spruce top weighs 3.06/2.82= 1.088, or about 9% more than the cedar. That's less than the number I got yesterday using a 50% difference in the density as an example, but yesterday's numbers would have been outliers in opposite directions for both woods; the cedar lower and the spruce higher in density than average. Again, when choosing wood for a top to give the desired response, you might well select an outlier; denser to give more 'headroom' and lighter for 'responsiveness'. In this example I used more 'average' values as a production line would. From what I know a 9% change in the weight of the top (without bracing) would be enough to produce a noticeable change in sound all else equal. If you use spruce bracing on both (as would be normal) the actual difference between the tops would be a smaller percentage, but still enough to matter, IMO. At any rate, the cedar top is lighter, even though it is thicker.

[nootis]

The knowledge on this forum never ceases to amaze me.

I too am having the Cedar debate, but vs. Redwood for my next commission. If I didn't already have 3 redwood topped guitars, my decision would be easy. However since I don't have a cedar topped guitar, I'm leaning towards making cedar a reality, but am also worried about headroom. I'm working things out with my psychologist, I mean luthier, at the moment.

[ataylor]

Originally Posted by justonwo

I think spruce - and especially red spruce - gets this weird reputation of not being able to do subtle, warm, complex pieces. Adirondack spruce is fantastic with fingerstyle. It also has fantastic headroom and volume.

I honestly think there is little a good piece of spruce can't do.

Agreed! Especially considering other factors — brand/builder, guitar shape, back/sides, bracing, strings, and, ultimately, the player.

Just wondering aloud: how many definitive finger-picked recordings were made with a spruce-topped, dreadnought-sized guitar?

[CarolynS]

Originally Posted by mcserres

Some say it won’t make a big difference (especially reinforced via p.a.)

Smart advice!

Originally Posted by mcserres

others swear cedar will breakup tonally when playong leadat volume.

That is a broad, inaccurate and not very smart generalization.

Order the guitar that you like and that you think will sound good acoustically, for your style of playing.

For live situations, just increase the volume as needed... For playing lead lines, if you need to cut through the mix, pick closer to the bridge.

[Guitars44me]

"For live situations, just increase the volume as needed... For playing lead lines, if you need to cut through the mix, pick closer to the bridge."

True!

And, I notice on Cedar topped guitars I can pick a bit closer to the bridge before getting that ice-pick tone.

Ymmv.

Paul