Classical guitar construction

[Donald A. Fortune]

Greetings to the classical guitar builders -- I have a question that needs to be answered-
I just received a set of plans to build a Jose' Ramirez classical guitar and the top and back seem to be flat rather than having a radius to it. is this the way it is made?????????
I will be attempting this guitar as soon as I get done making a 12 string dred. that I am working on now.
any help would be appreciated-- and thank you in advance for any replies....
Donald

[Donald A. Fortune]

Hi Bob -- I'm wondering what you use for materials to make your classical guitars--
I plan on using mahogny sides and back, and sutka spruce for the top.
Do you agree or no??
Donald

[Bob Webster]

My base instruments have Indian rosewood sides and back and either an Engelmann spruce top or cedar for the short scale guitars or European spruce for the full sized concert guitars. However, if this is your first classical guitar, there's nothing wrong with mahogany and sitka. I think you can expect a dryer, warmer sound out of the mahogany. As for the sitka spruce, it was a favorite of John Gilbert for its high strength to weight ratio.

If I remember correctly, the Ramirez plan gave top thicknesses appropriate for cedar. You might want to go about 10% or so thinner with the sitka as a starting point. The only down side to Sitka is that it's about 20% denser than Engelmann or European spruce. On the up side, it's pretty tough stuff and can withstand alot more in-process abuse.

Bob

[Donald A. Fortune]

Hey Bob - ya got to get a load of the info thats on the print--
Top -- sitka spruce @ 2.5mm or .100
sides--laminated rosewood @ 2.0mm or .80
back-- rosewood @ 2.5mm or.100

now heres where I'm having a problem with the info thats on the print--
there aint no way in my life time that I will ever use laminated wood
to make a guitar-- PERIOD !

the spruce seems ok for my first try, since I have some, and then if I do good then I will adventure in different materials.


I'm finding out by looking and comparing prints that the classical guitar
is a delicate guitar compared to a dred.
all of the material is much lighter in nature and the guitar must be a lot lighter too.
BTW-- got the form almost done-- gimmie a couple of days and I should be able to post a pic for you ok??

cheers--

[Bob Webster]

Gee, you're sure it's sitka? That would be extremely surprising. Ramirez set up all of his 1a's with laminated sides and was very successful. People have speculated why and the reasons are varied and interesting. Some say that it was to economize on the Brazilian rosewood, others say it was to protect the sides against splitting, and the third camp thinks it was strictly for tonal purposes. After all, it was cypress on the inside.

So..., don't say never. I've played several guitars that had double thickness sides, from laminating two full thickness sides and they were very loud, robust sounding guitars.

Classicals are, indeed, much more delicate than their steel-strung brethren. Very sensitive individuals.

Cheers,
Bob

[Donald A. Fortune]

Bob -- my print just calls for spruce, the reason I say sitka is because I happen to have a few tops that I got on a deal.. made a couple of guitars using the material and it reacts very well.
I want to make my first one as high end as I can possibly make it without breaking my bank, and that's the reason for mahogny for the sides and back.
I made a dred for my son in law here a few months ago and stained the mahogny with a dark walnut stain and I must say that it came out rather good looking, so I'm planing to do the same with the classical build .
now I have a theory about guitars and this is it--
the top of a guitar is like the head of a drum and it needs to vibrate a lot,
the back is like the back head of a drum but doesnt need to vibrate as much, and the sides are like the sides of a drum and need to be as stiff and non moving as possable,, agreed??
cheers,
Donald

[Donald A. Fortune]

UP date -- Well the form that I wanted to make is for the most part all done.. ( see pic)
Donald

[Cliff Morris]

Hey Don, Read through the Ramirez website some more in the history area. They claim in there that the laminate sides were for the tone blend of the woods. Not all Ramirezs had the laminations and if I understood correctly what I read it sounded like some were built that had laminations only in certain areas to bring out a desired balance. Check the family history portion and it sounded to me like there were squabbles over the changes to the instruments over the years.... Look in the FRETS.com side in the Gryphon museum and you will find a guitar from early last century that was made with a doubled floating back to help it resonate freely while being held. Just interesting stuff to check out. Christopher Parkening was quoted in an article some years ago as saying that the correct classical playing position was partly to minimize contact with the back of the guitar for resonant tone reasons. He must have gotten that from Andres Segovia as he studied with him for a number of years.

[Bob Webster]

Contreras designed two different models both of which had basically false backs. In one of them, there was a second back that was suspended from the sides and was made of either cedar or spruce. It was called the "Doble Tapa" model, which us gringos took to mean Double Top, but it was really a double back.

Bob

[Bob Webster]

Donald, I couldn't answer your "this is how I think the guitar works" post because there was no tag that would allow a response, so here it is.

Basically, you're right in that the top has the greatest freedom of movement. At the lower notes, it moves quite like a drum head but, unlike the dogma that's derived from Chaldni patterns, it's not a symmetrical response to the impulse of the string. With higher notes, the movement of the top is much more complicated, but then so is that of the drum head if you hit it in different places.

Depending on the design of the guitar, there can also be alot of sound radiated from the back and sides of the guitar. For the sides in particular, it's not necessarily advantageous to try to minimize it. For a classical guitar, the right stiffness in the sides just on either side of the waist bend can lead to augmentation of what the player hears when higher trebles are played. I have data for this and it was one of those real Ahaa moments.

Cheers,
Bob

[Donald A. Fortune]

Hi Bob -- I must admit that I'm not much of a sound engineer and one big problem that I have is that I'm hearing
challenged in as much as I can only hear out of one side-- now that doesn't mean that I am tone deef or anything because I can still hear a quality sound and I know when something isn't rite.... bur it sounds like your data thing is something that I would like to dubb into...got somewhere where I can get this info??
cheers,
Donald

[Bob Webster]

Not really. I have a ton of recording data that I've generated from a variety of guitars over the last five or so years. It's allowed me to map top vibrations on a note by note basis and it has been extremely informative regarding how guitars work when notes are plucked, rather than how they make Chladnis. I'm not yet sure a.) whether I want to share it out and b.) if I did, how would I disseminate it.

You have to understand that it represents a very substantial investment on my part in time both for the recording and analysis, time that could have gone into building guitars and selling them. Another aspect of my retiscence to share it out is because I'm not quite sure of the utility of the data yet nor some of the conclusions that I've reached. That said, there's some absolutely fascinating stuff there.

I might consider putting the recording and analysis methods into a blog here to show you what I do in general, maybe along with a map for a note. Please don't take my refusal to share personally. I've just been struggling with how to do it that would also protect my investment in some way.

Cheers,
Bob

[Cliff Morris]

Bob, Do you use any sort of "tap tuning" during your build? I have seen builders tap tune tops for steel string flat tops and I see in Robert Benedetto's book on archtop building that he not only tap tunes the top but also the whole assembled body. If I understand him correctly he tries to get the top and back to resonate in unison so they don't respond to frequencies individually that might be dissonant to each other. Would that be the reason for the laminates or vriations in stiffness on the classical sides?