Adi bracing vs Sitka bracing -- myth?

[BrunoBlack]

I have asked this question often and have looked for reliable technical information about both the differences and the resulting tonal response of using Adi bracing compared to Sitka bracing. I can't say I have found a completely satisfying answer. Adi is often cited as stiffer and lighter than Sitka offering more headroom, however the Wood Database actually lists Sitka as being slightly stiffer than red spruce, and their weights are virtually identical
( http://www.wood-database.com/#letter_s ).

I seem to prefer Red Spruce tops and I've chosen Adi bracing on my other guitars. And I've been happy with the results. However I do not feel like I understand the mechanics that control the reported differences provided by Adi bracing. The reported physical properties seem identical. To add to this uncertainty, the reported properties are only averages where any collection of Adi & Sitka brace stock has an extremely wide overlap of similar properties., In fact it would seem so similar that you would need to actually test the wood non-destructively before selecting it to understand the elastic properties of the actual piece you are working with.

So the short question: what is the difference and what different sound properties result from using Adi braces? And what is the basis for the conclusion?

[Ed-in-Ohio]

Originally Posted by Haasome

...snip...
So the short question: what is the difference and what different sound properties result from using Adi braces? And what is the basis for the conclusion?

In my opinion the only tonal difference comes from who shapes and attaches the braces (regardless of what species of Spruce they are made from).

This conclusion is based on my belief that when it comes to tone, the importance of the builder is almost always underestimated, while the importance of tonewoods is almost always overestimated.

[M19]

Originally Posted by Ed-in-Ohio

This conclusion is based on my belief that when it comes to tone, the importance of the builder is almost always underestimated, while the importance of tonewoods is almost always overestimated.

Hear hear!

[amac]

Originally Posted by Ed-in-Ohio

In my opinion the only tonal difference comes from who shapes and attaches the braces (regardless of what species of Spruce they are made from).

This conclusion is based on my belief that when it comes to tone, the importance of the builder is almost always underestimated, while the importance of tonewoods is almost always overestimated.

Not so fast... I agree with your statement, but why then do most, if not all, high end luthiers use Adirondack bracing? I'm not talking small, well known builders like Collings or SCGC, I'm talking the really exclusive builders selling guitars for $15k+.

Even though data may suggest both species of spruce are similar, I'm going to trust the builders decision to use Adirondack. If they say it's better, it must be better. 😉 (I know it isn't about the up charge.)

[Goodallboy]

Originally Posted by Ed-in-Ohio

In my opinion the only tonal difference comes from who shapes and attaches the braces (regardless of what species of Spruce they are made from).

This conclusion is based on my belief that when it comes to tone, the importance of the builder is almost always underestimated, while the importance of tonewoods is almost always overestimated.

I actually thought this had long been established as fact. And certainly in the question of the type of woods used for bracing.

[Toby Walker]

Jeff Huss at Huss & Dalton explained it this way, which I thought made perfect sense.

Adi bracing can be lighter, stronger, yet give more flex then Sitka bracing can. He went on to say that this is one of the reasons their guitars wind up sounding so darn good.

[MikeMcKee]

Was recently discussing this with Tom at Redwood Acoustics…specifically on SCGC guitars, and the fact that their upgrade option is for both Adi bracing and hide glue in combination. Apparently, in their thought, the benefit of Adi bracing is fully realized when hide glue is used. Personally, I think it's an incredibly good upgrade.

[BrunoBlack]

Yes, I've heard these comments too, but when I look at the data, I don't see an apparent connection to the claims about differences in strength-stiffness-weight.

SITKA
Average Dried Weight: 27 lbs/ft3 (425 kg/m3)
Specific Gravity (Basic, 12% MC): .36, .42
Janka Hardness: 510 lbf (2,270 N)
Modulus of Rupture: 10,150 lbf/in2 (70.0 MPa)
Elastic Modulus: 1,600,000 lbf/in2 (11.03 GPa)

RED SPRUCE
Average Dried Weight: 27 lbs/ft3 (435 kg/m3)
Specific Gravity (Basic, 12% MC): .37, .43
Janka Hardness: 490 lbf (2,180 N)
Modulus of Rupture: 9,580 lbf/in2 (66.0 MPa)
Elastic Modulus: 1,560,000 lbf/in2 (10.76 GPa)

Now, add to this that these values were established from physically testing thousands of samples for each species. The published values are averages for thousands of tests. This means if you grab a single Sitka brace and a single Adi brace without testing them first, statistically you have an equal chance of getting a stronger/stiffer/lighter Sitka as you do getting a stronger/stiffer/lighter Adi.

So, do builders have another metric or what's missing from the posted data?

Where red spruce and Sitka differ most is stiffness across the grain. Weight and stiffness along the grain are very similar. Since braces are little beams, the difference in stiffness across the grain makes little difference compared to the similarity in weight and stiffness along the grain.

While I won't claim there is no tonal difference between the two when used for bracing stock, I believe the difference in small compared to other factors. Claims like "...you get 90% of the red spruce tone for 10% of the cost by using red spruce braces..." are wildly exaggerated. I personally wouldn't pay any extra for red spruce braces on a factory guitar. I'd pay a significant amount for a red spruce top though.

FWIW, Martin used Sitka for bracing stock from the late teens or early 1920's onward, even though they used red spruce tops until the supply dried up. Those guitars turned out OK.

[SpruceTop]

Originally Posted by Toby Walker

Jeff Huss at Huss & Dalton explained it this way, which I thought made perfect sense.

Adi bracing can be lighter, stronger, yet give more flex then Sitka bracing can. He went on to say that this is one of the reasons their guitars wind up sounding so darn good.

The two Huss & Daltons I've owned, a DS Rosewood and a D-RH both sounded great and I agree with Huss & Dalton!

Originally Posted by Toby Walker

Jeff Huss at Huss & Dalton explained it this way, which I thought made perfect sense.

Adi bracing can be lighter, stronger, yet give more flex then Sitka bracing can. He went on to say that this is one of the reasons their guitars wind up sounding so darn good.

Among spruces commonly used in guitars, red spruce is both heavy and stiff, so I don't quite get that argument. That says nothing about the end result they achieve with their guitars, but I'm just not sure that line of thinking explains the outcome.

[lizzard]

With all due respect, the next H&D i play that I like will be the first. Same with Collings.

Sitka has the best weight to mass ratio as I understand (which is likely wrong) Red is the nostalgic "pretty boy" NOT THAT IS ISN'T GREAT.

But the pattern, thinning, height and nuance ----- A good builder can make something out of whatever NOBODY IS TALKING ABOUT.

Wait till you hear about the next trend of.... Balsa, Doug, White, Whatever.

Just my .02

Chris

[Larpy]

There's a well-known Collings dealer who in a moment of candor told me he didn't think you can hear a difference between red spruce and sitka as braces. I asked him why he orders so many Collings with adi bracing and he said "for just a little bit more money a customer gets a custom-made Collings, and that gives an owner a little extra bit of pride."

For him, it seems to be a business decision. I see his point, and I agree that the surcharge is modest (especially considering the cost of a Collings), but I also should point out that his store's website descriptions of adi-braced Collings guitars tend to use language like "we feel this feature gives the guitar just a little bit more resonance." Not exactly an actual claim of difference (due to the equivocation of "we feel"), but it contributes to the general perception that red spruce bracing is better.

[SpruceTop]

Bob Taylor mentioned in Wood & Steel a few years back that he felt Adirondack Spruce bracing gave the notes or tones a little extra spring off the pick or top (or something to that effect). True? Maybe or maybe not but when Bob Taylor speaks ...

[OddManOut]

Originally Posted by Haasome

Yes, I've heard these comments too, but when I look at the data, I don't see an apparent connection to the claims about differences in strength-stiffness-weight.

SITKA
Average Dried Weight: 27 lbs/ft3 (425 kg/m3)
Specific Gravity (Basic, 12% MC): .36, .42
Janka Hardness: 510 lbf (2,270 N)
Modulus of Rupture: 10,150 lbf/in2 (70.0 MPa)
Elastic Modulus: 1,600,000 lbf/in2 (11.03 GPa)

RED SPRUCE
Average Dried Weight: 27 lbs/ft3 (435 kg/m3)
Specific Gravity (Basic, 12% MC): .37, .43
Janka Hardness: 490 lbf (2,180 N)
Modulus of Rupture: 9,580 lbf/in2 (66.0 MPa)
Elastic Modulus: 1,560,000 lbf/in2 (10.76 GPa)

Now, add to this that these values were established from physically testing thousands of samples for each species. The published values are averages for thousands of tests. This means if you grab a single Sitka brace and a single Adi brace without testing them first, statistically you have an equal chance of getting a stronger/stiffer/lighter Sitka as you do getting a stronger/stiffer/lighter Adi.

So, do builders have another metric or what's missing from the posted data?

The data above are averages. Every set of brace stock will be different. There is much variation within a single species. On the seven different builds I have commissioned with Tahoe Guitars, weighing the brace sets has been part of the materials selection. Even though they were all Red Spruce, they all had different density. I currently have a set of Sitka brace stock set aside which is very similar in density to sets of Red I have chosen in the past.

Each builder will have their own opinions about what each type of brace wood brings to the table. Some swear by Red Spruce. Some feel Red gives a drier sound than Sitka, thus should be chosen based on desired tone. Some feel the brace species should match the top species. In the end, it is builder opinion and intuition.

I assure you big builders don't weigh or strength test their brace stock. If a buyer pays for upgraded brace material, there is no assurance that the Red Spruce stock that ends up on the guitar is strong/lighter/better than the set of Sitka which would have ended up on the guitar.

The perception that Red Spruce bracing is categorically superior to Sitka bracing is largely due to the overall market perception that Red Spruce is a superior material. This is the way with the market for consumer goods, guitars being no different.

The best Goodall (wet with overtones), and best Collings (quite dry) I owned both had Sitka top bracing. The tonal character of a guitar has so much more to do with the builder and design. Don't get lost in the minutiae of the brace species. My advice is that you concern yourself with the builder's overall sound.