Redwood top?

Construction and repair of Classical Guitar and related instruments
MrWopsle
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Redwood top?

Post by MrWopsle » Thu Jun 25, 2015 10:38 pm

The conventional wisdom holds that Redwood is like Ceder "plus." Redwood has more headroom than Cedar and perhaps more complexity and overtones (approaching Spruce). Assuming that the builder is the most important factor, what does Redwood bring to the sound of a guitar? Thanks!

Grebjohn

Re: Redwood top?

Post by Grebjohn » Fri Jun 26, 2015 6:13 am

Hi I'll only partially be able to answer this, as I have built a mandola with a sinker redwood top but not a guitar yet. On the mandola as compared to a Sitka spruce topped one I made, it had that more full bass sound associated more with cedar, but also quite bright trebles. Not as bright as spruce, but with sustain in the high register that almost equalled spruce. Assuming it's a well quartered set for the top, built by someone qualified, it will sound great. Also the few pieces I've handled have had phenomenal stiffness, cross grain as well, better than cedar and some engelmann, not quite as stiff as good Sitka, but was a bit less forgiving to work on. So I see it as, like you said (I think) a good balance between a spruce or cedar guitar, which is also subjective, and many people wouldn't be able to pick the spruces from the cedars blind anyways. Some people definitely, but not most. I also hear that the more figured pieces, while beautiful, are quite prone to cracking for what it's worth. Hopefully that was a little helpful and someone who has extensive knowledge of redwood tops will come along shortly.

John

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Anthony Campanella
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Re: Redwood top?

Post by Anthony Campanella » Fri Jun 26, 2015 1:13 pm

I came across a beautiful board and made this one
Redwood Guitar.jpg
It was built a bit stiff so I played it with silk and steel strings.
(Or maybe it was the sprayed lacquer)

I thought the material was stiff along the grain.
The stiffness variation between alternating grains - early/late wood - was very pronounced.
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Anthony Campanella
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Re: Redwood top?

Post by Anthony Campanella » Fri Jun 26, 2015 1:46 pm

I’m not sure of the availability; you may have to search far and wide:
Searching.jpg
If you do find some suitable material, protections are in place for the Sequoias, Coastal Redwood is still harvested
Found It!.jpg
Have a good weekend everyone and don’t forget to relax a little:
Relax.jpg
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Chris Sobel
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Re: Redwood top?

Post by Chris Sobel » Fri Jun 26, 2015 2:50 pm

Hello,

Redwood has the most variance in its internal properties (stiffness, density, etc) of any softwood species that I've seen in my shop. I've measured a density range of 350-420 kgm over just 4 sets! It goes without saying that the 350 density redwood will sound a lot more like cedar, whereas the 420 more like spruce. Now there are other properties that determine the sound but I use this example to bring up the point that it will depend a lot on the piece of redwood used.

I'll be honest, my preference is for redwood used in steel string guitars rather than classicals. That having been said I don't have a wide base of comparison. Also, in your initial post you imply that spruce has more overtones than cedar--not so sure about that; almost every cedar guitar I've heard tends to have more overtones than spruce. But you may be on to something in the sense that the steel string guitars I've heard with RW have had lovely and complex overtones.

Chris
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Waddy Thomson
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Re: Redwood top?

Post by Waddy Thomson » Fri Jun 26, 2015 3:56 pm

Redwood makes an excellent classical guitar. I have made one, which I mistakenly left the top thicker than needed, but have corrected that issue, by removing the bridge and thinning the top. I have also played Redwood topped guitars made by Steve Walter that were just incredible. Great power, projection and tone. Also looks great.
Waddy

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Chris Sobel
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Re: Redwood top?

Post by Chris Sobel » Fri Jun 26, 2015 4:50 pm

Waddy,

Good to hear your feedback and experience. Maybe you've inspired me to build a redwood...

Chris
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Waddy Thomson
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Re: Redwood top?

Post by Waddy Thomson » Fri Jun 26, 2015 6:37 pm

The key, in my opinion, is to read the wood like any other wood. Thickness based on the feel or stiffness. My mistake was to think I needed to treat it like Cedar, leaving it about 20 - 25% thicker than Spruce. I forgot to read the wood for itself. All tops need to be dealt with based on their individual properties/feel/sound.
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Marcus Dominelli
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Re: Redwood top?

Post by Marcus Dominelli » Fri Jun 26, 2015 8:43 pm

Waddy Thomson wrote:All tops need to be dealt with based on their individual properties/feel/sound.
This is really what it always boils down to IMO. Talking averages when it comes to soundboard woods is a pretty useless endeavor.
But there are some things I like and dislike about redwood in general:
1) very nice color variation. If you like character and color in top, redwood is great
2) it's kind of prone to splitting. Hairline cracks like to appear in redwood tops, just like they do in Braz RW.
3) it tends to be overpriced

Regarding that last point - overpriced. If you're just doing the occasional guitar commission for the doctor who just has to have a redwood guitar, then that's fine. But when you make a lot of guitars, switching from cedar to redwood is going to cost a lot more money. Here in B.C. you can get great cedar for about $10 a top, or less if you split your own. But most redwood dealers I've seen charge a lot for their wood. Usually justifying it's higher price by saying it's better than cedar, or "cedar on steroids" etc, etc. It's pretty much rubbish from my experience, which brings us back to the beginning - all tops must be judged individually....

MrWopsle
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Re: Redwood top?

Post by MrWopsle » Fri Jun 26, 2015 11:53 pm

Thanks for the replies. A clear picture is emerging.

Alan Carruth
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Re: Redwood top?

Post by Alan Carruth » Sat Jun 27, 2015 9:53 pm

Most of the redwood that I've seen is in the high density range: 375-500 kG/m^3. It tends to be a bit less stiff along the grain than it should be relative to the density. Sometimes it's due to 'compression wood': heavy late wood lines that contribute more to density then stiffness. At any rate, it's usually still pretty darn stiff along the grain, with decent cross grain stiffness, and damping that's very low for a softwood. The 'LS' redwood tops that I had had damping as low as Brazilian rosewood, and that's not all that uncommon in good redwood.

There is also bad redwood, of course. I ordered some a of year or so ago that looked OK, but had the tap tone of cardboard. The long-grain stiffness was also very low. I got the feeling that this wood had been crushed in some sense. Archer, in his 'Growth Stresses and Stains in Trees' talks about this. When a tree puts on new wood it's in tension relative to the wood under it, to avoid having the wood on the down wind side in compression. This puts the wood in the core of the tree into compression, of course, but that's not usually an issue for the tree. On really large trees the combination of the built in stress and the shear weight of the tree can exceed the compression strength of the wood in the core near the base, and cause microfracturing. You can't see it, but the wood lacks strength in bending along the grain, and the damping and density both go up. This particular batch of redwood was 'salvaged', and the supplier was proud of that, but I think it was probably from the core of a really big old stump, and had been damaged before the tree was cut. I sent it back: the only time I've ever gotten wood that I simply could not use for something. I've also seen redwood in lumber yards that had a sort of 'wadded up' look, with random changes in the runout that could well be related to the same sort of loading. The one or two pieces of that I tested also tended to be high in density and low in long grain stiffness. That was before had read Archer, so I could not account for why. Some of them, when sawn into tops, tended to crack while sitting on the shelf, possibly saving me the trouble of replacing them on a guitar.

At any rate, the high density and stiffness may well account for the added 'headroom' as compared with WRC. Cedar and redwood generally share lower damping than the spruces, so you'd expect them to sound similar. Because of the higher density you'd expect a redwood top to weigh more than a cedar one anyway, and if the redwood has compression wood that adds to the weight.

Peterson2

Re: Redwood top?

Post by Peterson2 » Tue Jun 30, 2015 12:21 pm

i think Redwood would be great used with the Ramirez 1A bracing as used on cedar Ramirez 1As 70s etc, with the big brace across the whole soundboard. i dont think this wood has been experimented with enough on classical guitar, it is a great wood, i think it should work better then Western Red Cedar. another under utilised North American wood is Douglas Fir. i have some samples at 4mm thickness, and the taptone is great, and i think it could make better guitars then Western Red Cedar also. all these different conifer woods though, i dont think stand up to European spruce, which transmits sound faster then any wood in the world.

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Waddy Thomson
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Re: Redwood top?

Post by Waddy Thomson » Tue Jun 30, 2015 6:32 pm

Peterson2 wrote:all these different conifer woods though, i dont think stand up to European spruce, which transmits sound faster then any wood in the world.
I might disagree with that statement! Some of my best guitars have been built with Lutz Spruce. Maybe I'm just lucky! That said, I've never tried to build two guitars exactly the same, using different top woods.
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Alan Carruth
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Re: Redwood top?

Post by Alan Carruth » Tue Jun 30, 2015 6:34 pm

Again, both redwood and Doug fir tend to be quite a bit denser than the wood I'd normally want for a Classical guitar. I've made several redwood topped Classicals, and they do sound good, but the added mass is likely to reduce the output a bit. WRC is often very low in density, which would tend to make it a better choice for a Classical.

peterson2 wrote:
"all these different conifer woods though, i dont think stand up to European spruce, which transmits sound faster then any wood in the world."

The speed of sound in a wood is simply a product of the density and Young's modulus: c^2=E/rho. Since wood is usually stiffer along the grain the speed of sound is different along and across the top. Also, this is the speed of a compression wave; we're usually more interested in bending waves, which are more complicated. The two are related, so knowing c is useful, but less diagnostic than it could be.

More to the point, though, there is so much overlap between species that it's not possible to make a blanket statement that one is 'better' than another in this regard. There is a close relationship between density and E along the grain which is the same for ALL softwoods, with surprisingly little scatter for a natural material. It's very nearly linear in the range of densities we see, too. This makes sense in that all softwoods share a very similar structure. If you want by statistical averages, Western red cedar tends to have the lowest density of the commonly used top woods, and given the normal relationship should have the highest speed of sound. It also tends to have a higher cross grain stiffness relative to the long grain than some of the others, and would gain there as well. Thus, if you want to make a generalization, WRC should take the palm among the usual suspects. And, of course, if you're talking about 'all the woods in the world', balsa should have the highest speed of sound.

European spruce does tend to have density that's only a little higher on average than Engelmann spruce, which, in turn, is just a bit denser on average than WRC. The spruces do tend to have higher surface hardness than cedar, which helps in practical terms. In the end, though, about the best you can say is that European spruce was probably the best top wood that European luthiers had to work with, so they used it. Since the designs we used evolved around the properties of the woods they had those are sort of 'built in', and tend to give good results by default, as it were.

Peterson2

Re: Redwood top?

Post by Peterson2 » Wed Jul 01, 2015 3:39 pm

Waddy Thomson wrote:
Peterson2 wrote:all these different conifer woods though, i dont think stand up to European spruce, which transmits sound faster then any wood in the world.
I might disagree with that statement! Some of my best guitars have been built with Lutz Spruce. Maybe I'm just lucky! That said, I've never tried to build two guitars exactly the same, using different top woods.
yep, you were lucky! and as you disproved yourself with the next line you gave.

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