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One of the mantras that I have come across in the guitar making community is that cedar is a great wood for fingerstyle instruments but doesn't have that much "headroom" to make a good driving rhythmic accompaniment instrument. A recent event has got me thinking more about this.

A few weeks ago I was at my annual guitar camp summer holiday in Burwell near Cambridge, learning guitar with Ed Boyd - a fabulous guitarist with the band Flook. On the thursday night the tutors give a concert and the up-coming young musicians (of which there are many) play as well. I have made a guitar for Joe Bardwell - a great young guitarist - and while rushing to get on stage during a downpour of rain, he tripped and managed to snap the neck of the guitar (luckily the break was a clean one that repaired well). He borrowed my cedar/maple Grand Concert guitar "Samhain" to play the set. My friend videoed it and has put it on Youtube. I was surprised and pleased at how well a Grand Concert sized guitar designed for fingerstyle with a cedar top stands up to some pretty heavy strumming in a purely acoustic setting - also in comparison to his usual guitar which is an inch wider at the lower bout, half an incher deeper and is spruce/mahogany. Joe literally grabbed the guitar and went on and one string sounds a little out of tune at the beginning of the set, but I hope you enjoy some great playing from Joe and a fabulously talented fiddler (and piper) Lizzy Doe:



This has got me wondering as to how much of a guitar's ultimate capabilities and performance comes from what you do with the wood as part of the overall design as opposed to just the topwood choice. I would be interested in experienced builders views but feel free to treat it as a rhetorical question or in Geordie's case - the chance for revenge

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Dave White
De Faoite Stringed Instruments
". . . the one thing a machine just can't do is give you character and personalities and sometimes that comes with flaws, but it always comes with humanity" Monty Don talking about hand weaving, "Mastercrafts", Weaving, BBC March 2010

Dave,

I am certainly not in a position to be telling you anything about guitar design. But what you ask here could simply be a case that those who have commented on such things in the past as this top wood having more of this and less of that than another, may simply have been their opinion based upon them using a top with a design they have become comfortable with, rather than designing a guitar that the top in question would have been comfortable with?

Oh, and another great guitar and well earned kudos to you Mr White

Cheers

Kim

It rains in England?

I was there in July and can attest that it rains for only 15 minutes at a time, interrupted by 15 minutes of non rain, then repeats.

So, how was camp? Sounds like fun.

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Expectation is the source of all misery; comparison the thief of joy.
http://redrivercanoe.ca/

Dave, you know my opinion as we have talked about this. I think that this talk of 'headroom' for different woods as a generalisation is a load of twaddle. It is so much down to the individual piece of wood and to the building techniques of the builder. Your designs add a lot of lateral stiffess to the top, this has as much to do with the ability of your guitars to be good with the finger and the pick ( though I'm still not sure with his recent history I'd have let him use my guitar!) It's down to each piece of wood and each builders use of it.

Colin

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I don't believe in anything, I simply make use of a set of reasonable working hypotheses.

As a musician, I have to wonder still....how much of this is the players touch and approach to the instrument? I have a cedar topped dread that can be as mellow as a classical or as stiff as a D-18. It all depends on how I approach playing it. If I strum an instrument and it has one tone, I may adjust my playing technique to accomidate a different tone. EX: If it is not bright enough to cut thru the mix, I may play closer to the bridge...or vise versa. This is an automatic thing for me and not a conscious thing that I can tell. I think any top tone-wood can be somewhat versitle regardless of design. The design can assist in the final output, but to some extent, the overall sound starts with the player. Each instrument will have a sweet spot where it sounds best when played for a particular style of music. Finding that spot is the magic to me.

While at the Chicago get-together, I played 4 or 5 handmade guitars. Some I had to work harder than others to make sound nice, but in the end, they all captured what I was conveying with my music. It wasn't so much work as it was unfamilarity with each instruments sweet spot. It took some time with each instrument to find that voice. In this video, it sounds like he also finds the "voice" as he continues to play on.

On the other hand, if your talking about pure compression of the guitar, I would think the box would play as much of a roll in this as anything. I am not convinced yet that the top is the only factor to the headroom. (I define headroom as the amount of dynamic db levels between no sound and when the instrument does not get any louder regardless of how hard it is played. At some point the instrument will compress instead of getting louder.)

YMMV,
Joe

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Joe

It seems to me right now (and I could change my mind in a trice), that the density of the top wood plays a part, as well as the brace profiles and bridge weight. I think that 'headroom' has to do with how hard it is to drive the instrument into a non-linear response range. The way to avoid that is to have relatively high impedance at the driving point: 'tapered' rather than 'scalloped' bracing, a thick and/or dense and stiff top, and a heavy bridge should all help. Of course, as usual, there are limits to this; you have to balance things like volume, responsiveness, and sustain with the desire for lots of headroom.

IMO, the reason cedar gets a bad rap is that people tend to leave it a little on the thin side, so it lacks the stiffness and mass it needs. Without knowing the density and stiffness of your top, and how thick you made it, it's hard to say. I've made cedar topped guitars with plenty of headroom, so I know it's possible.

This is all opinion, without much 'data' to back it up.

At the moment this all seems like voodoo

I'm sure at around no 10 I'll start to understand a little more

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Formerly JJH

I learn more from my mistakes than my successes

Alan, if you'd be willing to explain/elaborate on this phrase, I'd appreciate it.

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Todd Rose
Ithaca, NY

https://www.dreamingrosesecobnb.com/todds-art-music

https://www.facebook.com/ToddRoseGuitars/

I would like some explanation of how the placement of tone bars affects tone. Like what do you do to make a guitar have more low end or what do you do to have more treble?

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A higher purpose for wood.
Rich Smith
Issaquah, WA

Todd, to me, this means that as you play the strings more aggresively, the volume or the output gets louder in a linear fashion. At some point, no matter how hard you play the strings, the volume does not change. It becomes flat. Headroom is the distance between the softest note you can play and the loudest note you can play accoustically. Anything above that level is compressed by the design of the box. It can't get any louder, but its tone can change anyway. So in theory, after it hits the top of the headroom, it could loose clarity, or gain more harshness, or in some case, I suppose it could get warmer or thicker. Mostly it would distort tone-wise.

Joe

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Joe

Joe,

I couldn't agree with you more about the role of a player with a guitar and a great players ability to find and adapt to each instruments character and strengths. The same is true in the eternal debate about intonation - the most important element is a players fingers.

Kim,

I'm guilty as charged with many others here - the design of all my various instruments are pretty common in their elements, but I do treat each top in terms of how it responds and thickness/brace accordingly irrespective of wood type. I use the "vodoo mumbo jumbo" techniques of my hands, brain and ears rather than deflection or Chladni patterns - mainly I suspect because I spent 25+ years working in very scientific/data hungry environments and relish the change in approach. The guitar Joe used is over 2 years old by the way and I'm really pleased with where it has got to - I believe that you need to build with a view to where the instrument's sound will go in this time and sometimes this means that the out of the blocks sound is not "total killer". Sometimes those that are built to sound that way mature to a sub-optimal place. Builders and players need to learn this patience imho.

Colin,

It was a pleasure to hear Joe play this guitar and taught me a lot. I do confess that it came back with a few more pick marks than it left with and needs a little tlc before it's Cheltenham Show appearance.

Alan,

That's interesting. I agree with you about the reputation cedar seems to have. I couldn't tell you anything about it's density, but it was 3.2mm in the centre and probably 2.8mm around the lower bout perimeter. The bracing was tapered and it has a pretty big arch in the top and back - around 13' radius on the top and 10' radius on the back. The bridge is Kingwood (dahlbergia cearensis) and pinless and on this guitar I used a Lutz spruce bridgeplate with the grain running parallel to the top:



Ricardo:

There are lots of ways you can influence the tonal balance of an instrument but the placing of the tone bars wouldn't be the top of my list of places to start.

JJ:,

Don't worry - when building your first there are lots of other more pressing issues to consider.

Douglas:

Camp was great. It was sandwiched around the English monsoon seasons and it only rained a couple of times.

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Dave White
De Faoite Stringed Instruments
". . . the one thing a machine just can't do is give you character and personalities and sometimes that comes with flaws, but it always comes with humanity" Monty Don talking about hand weaving, "Mastercrafts", Weaving, BBC March 2010

Todd:
'Linear' simply means that there is a simple relationship between the input and output. In the easiest case, twice as much power in gets you twice as much power out, but it could be 2x in gets 1.5x out, so long as the same relationship holds at all power levels. The point is that if you graph input vs output, you always get a straight line.

For the most part, guitars are pretty close to linear. However, at the extremes, and especially when you try to drive them hard, they don't seem to be. At low power levels there's always a little flex left in the braces, but at some point they run out of 'give'. That's when the sound changes. You can get 'clipping', with the tops of the wave forms chopped off, so that a nice smooth signal suddenly gains a lot of high-end noise, for example.

A heavier, stiffer top is going to move less for a given input, so it might not be as loud as a lighter top when driven lightly. However, the light top will tend to reach its limits at a lower power level, and start sounding odd. The woods used and the design both contribute to this for sure, and maybe some other things as well, such as the glue used and overall 'tightness' of the build.

All of this needs to be studied a lot more, which is pretty normal in this business. If we could tie in high-end guitars to National Security we could get al sorts of funding for research, and would know a lot more than we do. As it is, we'll just keep disCUSSing it on e-mail lists and 'boards such as this.

Colin I have a ton of respect for you and not enough actual experience to disagree slightly but find myself doing just that.

I feel if you where to take an exceptional piece of Red Cedar and an exceptional piece of spruce that the spruce would have more headroom due to the spruce fibers being longer and thicker walled than red cedar fibers.

So theoretically a skilled craftsman building for headroom could take advantage.

Why do I think slightly thicker walls and longer fibers matter?

heavier load/impedance can be handled by the thick wall and it is spread over a larger area by the longer fibers X millions of fibers = lower frequency and higher input until clipping occurs.


That's my theory and I'm stickin' to it!!! OK?

Sorry can't help my self. I am worried because stepping on superman's cape can be followed by one bad ##s smack-down.


respectfully challenging,

Kirby

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"It's a Tone Faerie thing"
"Da goal is to sharpen ur wit as well as ye Sgian Dubh"
"Sippin Loch Dhu @Black lake" ,Kirby O...

Ok kill the it is a little much.

If I remember correctly Al has stated that young's modulus pretty much tracks density when dealing with longitudinal stiffness and is a little scattered when dealing with cross grain stiffness.

This is a link showing what Larry Stamm found,

http://www.larrystamm.com/wood_testing.php

At first blush Red Cedar having a higher stiffness to weight ratio in cross grain stiffness would seem superior.

I feel in practice though the with the grain stiffness adds an amount of support to the cross
grain stiffness and tilts things favorably towards spruce.

Please bear with me if I am not presenting this well.


To me in general it all seems to track fiber length, width, and wall thickness.

averages(paper mill figures)

Doug fir: length 3.5mm, width 42 microns, cell wall thickness 4 microns

Spruce: length 3mm, width 30 microns, cell wall thickness 2.2 microns

R cedar: length 2.6mm, width 28 microns, cell wall thickness 1.6 microns

I also feel that they play in (react to stresses) differently and that is very important.

Here is an old study that to me seems to support that idea, it only deals with Doug fir and spruce but given my theory about fibers I think some postulation on cedar is acceptable.


http://ir.library.oregonstate.edu/dspace/bitstream/1957/1388/1/FPL_1325_ocr_text.pdf

Hope I have made some sort of sense of why I believe the potential for spruce to have more headroom exist?

Kirby

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"It's a Tone Faerie thing"
"Da goal is to sharpen ur wit as well as ye Sgian Dubh"
"Sippin Loch Dhu @Black lake" ,Kirby O...

Got it, Al. Thanks. I appreciate this thread a lot. It's helping me get a better grip on an important issue.

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Todd Rose
Ithaca, NY

https://www.dreamingrosesecobnb.com/todds-art-music

https://www.facebook.com/ToddRoseGuitars/

Kirby,

I hear what you say. I expect that spruce probably does give you potentially more headroom - with Colin's caveat (and Al's in the past) that it depends on the individual piece of wood. What I find interesting - and have learned from this - is that you can also build around a piece of wood for certain headroom. It then comes down to how much headroom do you need for a particular application and within those limits how do you want to colour the sound and tone. This widens the palette and choice for the builder rather than immidiately reaching for a good piece of spruce.

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Dave White
De Faoite Stringed Instruments
". . . the one thing a machine just can't do is give you character and personalities and sometimes that comes with flaws, but it always comes with humanity" Monty Don talking about hand weaving, "Mastercrafts", Weaving, BBC March 2010

"with Colin's caveat (and Al's in the past) that it depends on the individual piece of wood. "

Always!

"What I find interesting - and have learned from this - is that you can also build around a piece of wood for certain headroom."

Dave I am taoistic in my view of the physical universe in the sense I believe all things seek equilibrium,

translated: I am fascinated by trying to figure what the trade-off is.

Dave one of my favorite songs to play is Kenny W. Sheppard's Blue on black. I like it best when I bang the bass and moderate the treble a bit other wise it becomes treble dominated and to me changes the whole feel it also has a solo that to me wants lightish bracing(best achieved with two different guitars but is it really do one thing with excellence or two with mediocrity?). I can see the chords sounding best on a cedar built for headroom.(oops edit: add what I thought but missed typing) I feel you might have found the right recipe to do the whole song very very well!

With a bluegrasser the point of headroom is to bang the snot out of the strings, be a "Banjo Killer" and cut thru. It practically demands the stiffest spruce.

Are these two different types of headroom? If so can they be best served using different methods to achieve it or am I way out in left field.......?

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"It's a Tone Faerie thing"
"Da goal is to sharpen ur wit as well as ye Sgian Dubh"
"Sippin Loch Dhu @Black lake" ,Kirby O...

Kirby:
I'm not convinced by your reasoning. Why would feature sizes well below the wave length of the sound traveling in the wood effect the tone or headroom? Millimeter wave lengths are 'way up in the ultrasonic range. I'm sticking with my idea that it's got more to do with actual stiffness and mass than anything else. The trick is, of course, that given the differences in density and so on, it would be hard to make, say, a WRC top that had 'the same' overall properties as a Red spruce one, at least with 'average' wood of each species. I do have Red and WRC top blanks with 'the same' stiffness and density, and plan to make a 'matched pair' of guitars from them one day. Then we can see which has more 'headroom'.

Al it is not about sound traveling in the wood. It is about the actual amount of excursion of the soundboard which would be mm(I think).

Density always matters
low amplitude = smaller mass/surface area and less excursion
high amplitude = larger mass/surface area larger excursion

Longer fibers joined together handle the further excursion better by spreading it out over a larger area.

In an effort to express myself simply I left out factors I don't have much knowledge of such as the elasticity of the fibers and the elasticity of the bond between fibers and maybe others that I have no clue exists, yet.

What is happening as they play in do some fibers stretch as others work harden or even rupture. Do different woods handle the stresses differently.

With humility 'cause it is easy to be totally wrong.



"I do have Red and WRC top blanks with 'the same' stiffness and density, and plan to make a 'matched pair' of guitars from them one day. "

in order to isolate the top woods amount of influence every other part especially bracing would have to be extroidinarily consistent. Carbon fiber?

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"It's a Tone Faerie thing"
"Da goal is to sharpen ur wit as well as ye Sgian Dubh"
"Sippin Loch Dhu @Black lake" ,Kirby O...

edit:

Al it is not about sound traveling in the wood. It is about the actual amount of excursion of the soundboard which would be mm(I think).

should read:

Al it is not about sound traveling in the wood. It is about the actual amount of excursion of the soundboard which would be microns-mm(I think).

sorry I really do have concetration problems.

this is a link to an that shows an electron micrograph of spruce to help visualize things (for those who have not seen a representation)

http://www.astro.cf.ac.uk/groups/acoucomp/MAGGuitar.html#constr3


looked for the same for WRC and DF but could not find them.

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"It's a Tone Faerie thing"
"Da goal is to sharpen ur wit as well as ye Sgian Dubh"
"Sippin Loch Dhu @Black lake" ,Kirby O...

Kirby:
We're talking about bending waves here, so what counts is the bending stiffness of the top. All of the stuff you're talking about, fiber length, wall thickness, and so on, effects that, I'd guess, in that it should have an influence on the Young's modulus (E) of the wood. but that's only part of the equation in bending stiffness; you also need to think of the thickness of the piece. A thick piece of WRC, with a low E value, can be just as stiff in bending as a thinner piece of Sitka with a much higher E.

Now it's possible that fiber length or some other micro-variable could also effect something like the transition from linear to non-linear bending. I don't know enough about the physics of stuff at that scale to be able to say. I've seen enough micrograhs of softwood to have a pretty god idea of the structure, and it seems to me, iirc, that all of the soft woods are pretty similar. I have been told by those who claim to know, for example, that it's often impossible to distinguish different spruce species even under the microscope. What we need to do is study microstuctural effects: figure out where, in terms of stress and strain, that transition occurs, and see if that relates to something like fiber length, wall thickness, lignin bonds, whatever. That would be an interesting set of experiments, and I hope somebody takes it up. I sure don't have the time.....

Until then, absent some data on how this stuff works (if it does), I'm going to remain unconvinced. At the moment I don't see the need to invoke causes we can't see when it's entirely plausible that ones we already know about will suffice.