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Folks,

I've built one classical so far using redwood for soundboar material. It came out sounding pretty good, really, although I think I got the top just a bit too thin.

I'm curious, though, if any of you have build classicals using redwood, and if so, how does it compare with a good quality spruce?

Volume? Sonority?

I know that a number of steel string builders, including Lance, have had good luck with it as a tonewood, but other than my own build, I've only run across one other classical built with redwood -- an Oribe 10-string. It was a nice-sounding guitar, but I did not have the opportunity to spend much time with it.

Best,

Michael

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If I am not mistaken it has very similar properties to Wester Red Cedar and a lot of classical makers use cedar. Red Wood is probably shaded a little toward the spruce side of cedar. Though I have never used it for classicals, I see no reason why it should not be an excellent choice.

John

I've always thought of redwood as a sort of 'super cedar': it's more like cedar than cedar is!

All woods are quite variable, of course, and redwood is as variable as any. On the average I'd say it is a bit harder, stiffer, and denser than cedar: I've just tested some redwood tops that are denser than Sitka spruce! It's most consistent characteristic is low damping: redwood can 'ring' like good rosewood. This can impart either 'warmth' or 'brightness' to the tone, depending on how you use it, and you can easily get both.

I've used it in steel string and classical guitars, as well as archtops and fiddles, and like it. It seems particularly 'happy'with walnut or mahogany B&S wood in a guitar, and I suspect koa would work really well, too.

Richard Schneider built his Kasha-influenced classicals with redwood tops AND backs! And they are loud.

Interesting about Schneider. I have a lot of respect for his innovation, and have even incorporated his "flying tone bar" concept into one of my own bracing patterns.

[QUOTE=Alan Carruth]
All woods are quite variable, of course, and redwood is as variable as any. On the average I'd say it is a bit harder, stiffer, and denser than cedar: I've just tested some redwood tops that are denser than Sitka spruce![/quote]

I just tested a nice stiff set with a bright metallic tap tone. I'm getting about 3g/cm^3, compared to a little over 4g/cm^3 for a nice set of Engelmann I have. It's stiffer than the Engelmann. 3g/cm^3 seems to be kinda light to me, but I haven't done much in the way of density measurements with soundboard woods.

[quote]I've used it in steel string and classical guitars, as well as archtops and fiddles, and like it. It seems particularly 'happy'with walnut or mahogany B&S wood in a guitar, and I suspect koa would work really well, too. [/QUOTE]

I've used it with padauk so far, and that combination seems to work well. The guitar has plenty of volume, but the sound is somewhat thumpy. I suspect this is because I took the top down a bit too far. It was a very stiff top, so I thicknessed it to where I usually thickness spruce, about 0.085". My next redwood build will probably use either cocobola or EIR for the b&s.

So got another question for you, Al -- given a very stiff, perfectly quartersawn set of redwood, what would you consider to be an optimum thickness for it? I'm thinking somewhere around 0.095" to 0.100".

I'm also probably going to brace it with Spanish cedar instead of spruce or redwood, most likely using an extended radial pattern that I've developed. I had the chance recently to examine several quality classicals, including a Byers, a Sahlin, an Oribe and a Bernabe. Only the Byers used spruce as bracing material for the top. The others used either Western redcedar (the Sahlin) or Spanish cedar (the rest). I was kinda suprised by that.

Incidentally, the Oribe had a redwood top, and sounded quite good. But it wasn't really a standout compared to the rest. The standouts were the Byers and the Bernabe (both of which had cedar tops).

Best,

Michael
Michael McBroom38552.9513194444

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I have built a few classicals with Redwood and echo all Alan Carruth said. I like it alot but there is such as range of stiffness and density that I usually opt for WRC (Ed Dick of AC Woods, a OLF sponsor has great wood) as it is more consistent to what I am used to. I have tried tight old growth vertical grain, wider softer grain, bearclaw, and curly (both wide slow curl and fast narrow curl) redwood.

One thing I would add to the discussion is that instead of taking tops down to a uniform thickness, it is safer to take them down to a relatively uniform stiffness, not necessarily thickness. Because Redwood is so variable it is even more so than say Sitka. I have had Redwood that would dent from a shaving left on a bench and I have had other that was as tough as Sitka.

If I have a top that is light but stiff then I try to leave the working thickness about .010 thicker than a Spruce top which is generally what I do for Englemann and WRC tops but not needed for Euro spruce. If a top is dense and stiff then I may take it down thinner.

There are many thoughts as to how thin a classical top should be but for the most part I try to use stiffness as the measure and then thin as needed as I am voicing the tops. .085 (~2.1mm) is not too thin for a classical top but if you leave it in the 2.2-2.3 range you have more wood to leave if the top is less stiff. Different regions of my tops will range from 1.9mm (~.074)to 2.4mm (~.100), all dependent on the stiffness of the top and where I need to shape the tone based on "glitter tests"

I started out knowing only how an old school violin builder would tune or voice tops using the tap thud that different parts of the head are tuning to...it was all subjective but eventually I began to hear and feel the sound I was building for...then 2 years ago at the 2003 A.S.I.A. Conference I sat in Alan Carruth's voicing session where he showed his use of Chaldni "glitter patterns" to refine the sonority of a top and it has really helped...I now not only can judge subjectively what I think the tone of the tops will be, I can then measure it and see how close my ear was...I am getting much more consistent voicing and projection now (Thanks Alan)

I made a redwood/bubinga classical a while back. I hate to say that it probably turned out to be the worst guitar I've made to date. But thats not to say that someone could not make a good sounding classical with redwood. I think I left my top a little to thick. The worst problem with it is volume. It's to quite. The treble is also very mellow.
Here is a picture of it.

Shawn:
Glad that's working for you. I think the _shapes_ of the patterns 'mean' more than the frequencies, but the frequencies certainly help you figure out how stiff it is.

Michael:
That sure is a light top! I just tested about thirty tops, and the redwood ones I've got (two LS tops and a couple of lumberyard specials)were all close to 500kg/m^3. The only tops I had down near 300 were some Euro and Englemann ones.

The problem on a guitar is that you need both the static stiffness to withstand the bridge torque and a light structure that will sound out well. These are incompatable objectives, but the bridge torque sets the limit.

The stiffness of the top will be proportional to the Young's modulus and the cube of the thickness: a given piece of wood twice as thick will be eight times as stiff. The weight will be a function of the thickness and density. Supose you have two pieces of wood: say one of Doug fir that has a density of 600kg/m^3 and your redwood that runs around 300. Suppose also that the fir has a Young's modulus twice as high as the redwood, which would be reasonable (so we'll call the E value of the redwood '1' and that of the fir '2'). Let's say you figured out somehow that the redwood top would be stiff enough at 3mm thick, and the 'bare ' top, with no bracing, weighed 100 grams. To have the same weight the fir top would have to be only 1.5mm thick, but it would be much too floppy. The redwod is 3x3x3x1=27, while the fir is 1.5x1.5x1.5x2=6.75: only 1/4 as stiff! Even though the fir wood is 'stiffer' it still would make a heavier top. Usually that's considered a bad thing, particularly in Classicals.

I tend to make my tops a bit on the thick side: you can always take some off later if you need to and it will work out OK. I'd start with that redwood at about 2.5-2.7, and taper it back from the bridge to about 2.0 at the tailblock, but that's only my system.

Alan,

Sure appreciate your explanations. They were quite clear. But then I'm kinda geeky, I guess. I actually like subjects like math, physics, chemistry, and biology.

The top piece I measured yesterday had a bit of variability in its thickness, which I attempted to average out the best I could. But after reading your note, I decided to measure a piece of the plank I resawed it from, figuring that a larger, smooth cut piece will give me a better measurement.

(Yup, this set came from a nice plank I found in a lumberyard. I have one LS set, but I'm saving it for a special occasion :)

The plank, as well as the top set, has been in a 50% humidity environment for about a year, so the moisture content shouldn't be affecting the measurements.

After crunching the numbers, I still got 391 kg/m^3, so still somewhat on the light side compared to your numbers.

I am in agreement with your thickness estimates. It's always easier to take off wood than it is to add it back on. :) I like to taper my tops out toward the edges of the lower bout as well as the tailblock.

Shawn, thanks very much for your explanations as well. I'm still kinda new to the whole subject of voicing and feel like I'm all alone in the wilderness at times. :) Still real seat-o-the-pants around here, although the builds have been coming out nicely for the most part.

Best,

Michael

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Folks,

I thought I'd ask the listmind one more question about redwood tops. What is your preferred bracewood?

This guitar will be a classical, if that would make a difference in your selection.

I've built two nylon string guitars with redwood tops so far, one classical and one =ahem= experimental model. With the experimental one I used a lattice bracing scheme, and used redwood for the lattice bracing. With the classical, I used Euro spruce for bracing, and braced it according to a traditional Torres/Hauser pattern. The second guitar sounded much better than the first.

I have examined some outstanding classicals whose soundboards were braced with Spanish cedar and even Western redcedar, as well as spruce. These were cedar and spruce topped instruments, though.

At this point, I'm seriously considering using Spanish cedar. It's light, relatively stiff and it smells nice :)

Best,

Michael
Michael McBroom38558.8878240741

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Live to Play, Play to Live

Cedro should work fine. I'm a little leery of redwood and cedar as brace woods, as they lack the toughness of spruce. OTOH, I'm not too proud to use anything that has the 'right' properties.