Different Spruces -

[mcduffnw]

Originally Posted by Alan Carruth

The equations we use to derive the Young's modulus from vibration tests are approximations that only get close to the 'right' answer. McIntyre and Woodhouse published some articles on all of this, also in the JCAS, in '85 and '86. They gave some hints about using results of several modes in rectangular plates tuned so that the lengthwise and crosswise 'pure' bending frequencies would be the same, to account for shear moduli and Poisson's ratios and get better 'E' values. None of this is simple...

And...very importantly to the builder, be they factory, small boutique factory, or solo or small group luthier...none of it is simple, and it is time consuming to test...and time IS money...or production cost...for any and all the builders.

It might be one thing is someone is a builder who can command $20K and up and up for their guitars, so they can build in the testing time costs and still come out in the green, but isn't likely a viable scenario for large output factories or small output makers who can't charge the big BIG bucks.

And really...all the testing in the world/building by highly scientific method is no guarantee of absolute success and/or better and more consistently superior sounding guitars. Of the luthiers, like Trevor Gore, who are working to varying degrees in this way, there is no big buzz out there in the guitar community saying that that the high science high testing high test data reliance style makers are building more consistently much better sounding guitars than ABC or XYZ guitar makers who build in the more old school touch and feel, hands and hearts, eyes and ears and instincts style.

I think, through the years out here on the AGF Mr. Carruth has been gently and kindly trying to say this...that all the testing and data are good to know and understand, but at the end of the day, the builder is still going to have to make educated guesses in the process of building any given guitar, and the educated guesses may be as much or more by experience, instinct and gut feeling as they are by researched data points.


duff
Be A Player...Not A Polisher

[RussellHawaii]

For custom builds I’ve found it useful to let the luthier recommend the wood. They know their own experience and how things turn out in reality, all theory aside. Some builders will produce better guitars with Species X even tho Species Y is more highly regarded. I trust their judgement and first hand experience.
I was a dedicated Adi guy based on its reputation. One luthier told me that most wood sold today as Adi is probably not in fact, Adi. I don’t know… Also, as Adi is scarce, it may be much easier to find exceptional boards of Sitka or European, as they are plentiful.
Another builder said he has some Lutz spruce that’s among the best spruce he’s ever seen. I believe him, and would never have known to consider Lutz. It’s about the batch of wood and how the builder works with it, not purely the species.
And a couple luthiers have commented that the individual boards vary more than the species, as some have said here.
My point is a luthier knows how their woods will turn out, much better than we as customers can guess. Listen to them!

[zmf]

Originally Posted by mcduffnw

And really...all the testing in the world/building by highly scientific method is no guarantee of absolute success and/or better and more consistently superior sounding guitars.

True. But one useful aspect of these "approximate" numbers is that it sheds light on what CANNOT be assumed.

Perhaps to the consternation of those whose belief systems allow them to know exactly what wood species are needed to produce a particular sound.

Always good to let a little light shine in, even if all is not revealed.

[Glennwillow]

I have guitars made with red spruce/Adirondack spruce, sitka spruce, Italian spruce, and Engelmann spruce. They all sound good to me. I also have 3 guitars with western red cedar tops, and they definitely sound different compared to spruce tops.

I have never had a chance to play the same guitar but with different spruce tops where I could make a direct comparison, so that I'm not sure that I really know from direct experience that there is a difference in tone or response. I have tended to take the manufacturer's word that there is a difference.

I'm kind of in the same camp is the OP. I have purchased the guitars that sounded good to me. The rest of my background on tops is more like theoretical knowledge. The luthiers out there who build guitars tend to comment that there is a great deal of overlap in character between the various spruces. I have looked for good, responsive sound; I'm not trying to split hairs.

- Glenn

[mcduffnw]

Originally Posted by zmf

True. But one useful aspect of these "approximate" numbers is that it sheds light on what CANNOT be assumed.

Perhaps to the consternation of those whose belief systems allow them to know exactly what wood species are needed to produce a particular sound.

Always good to let a little light shine in, even if all is not revealed.

Maybe I am reading or understanding your point wrong...but...

How is an "approximate" number going shed any light whatsoever on what cannot be assumed. It just kind of reinforces the point that even with given data points, luthiers still have to make educated guesses and follow instincts and past experiences in their craft.

That's the working problem...approximate is just that...approximate. It is not definitive...there is obvious and not so obvious wiggle room in the data as to how it represents whatever item it is measuring.

It's like Mr. Carruth has said ever so many times over the years in regards to the noted differences or assumed differences in the tone and response of the various spruces...that when you control for density and stiffness...spruce sounds like spruce regardless of species.

So no matter the data points...the various spruces...under the hands of a skilled and alert luthier...can be made to sound very much alike.


duff
Be A Player...Not A Polisher

[zmf]

Originally Posted by mcduffnw

So no matter the data points...the various spruces...under the hands of a skilled and alert luthier...can be made to sound very much alike.

I was coming at this from the perspective of someone (me) who is relatively ignorant about what to suggest if I was to commission a guitar. Seeing numbers graphed out appeals to me, even when I already fully buy into what the more knowledgeable folks have been telling me about overlap between species. I like to stare at raw data. And I would guess that skilled luthiers would like to do the same, even if they are already accomplished in their trade.

Guess my point is that more knowledge is good, even if it's not currently making a significant contribution to building guitars.

At least I know, based only on one study, that some species many cluster with a couple of variables, while others may be all over the place. And that apparently these variables don't correlate with damping. And that aging wood may produce greater overlap between species.

And it helps to discount the noise on the subject that is prevalent on the internet.

[Alan Carruth]

Looks like I need to work at getting my point across better! I do believe that testing and science can help us improve our 'standard of mediocrity': we can make the average better and build fewer duds when we know more about how these things work, and the materials we're making them out of. I have found it worthwhile in my own work, and know of a number of other luthiers who have done the same.

Man-hours are the most expensive input in a factory setting, in part because they have so much capital tied up in speeding up the process and making it more dimensionally repeatable. Taylor's 5-axis CNC machine for cutting neck pockets cost about $250,000, if I remember his talk right. Given the way such things work it probably cost them that much again to put up the building it's in, and a lot more to program in and iron out the bugs. They probably had close to $700,000 in before they got a single usable neck pocket cut. With that sort on investment you have to keep the machine busy, and you can't be standing around tapping on tops while it stands idle.

Most one man shops have some such tooling, but nowhere near that level. We can afford take the time to measure the properties of every set of wood we use, if that's what we think is appropriate. Not every hand maker agrees with that.

I use the measurements I get to determine the 'proper' thickness for each top, depending on the wood properties. I also use them to decide which type and shape of guitar to use a particular top for: lower density tops go on Classical guitars, for example.

I also believe, based on my experience with science and measurements, that it's probably impossible to make 'identical' sounding guitars. But, on the same basis, I know you can get 'arbitrarily close' to a desired sound by matching the right measurements.

Guitars are very complicated beasts, and wood is extremely variable. As long as we make them from wood it will never be an exact science, no matter how we try. But we can improve the breed, and avoid problems by making use of the science we have. As with any measurement, there's always the judgement of when you've gotten 'close enough', but that doesn't mean that we can substitute intuition for measurement whenever we like. Does anybody cut fret slots by eye?