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

[Cliff Morris]

Just thinking about your testing a bit and it makes me wonder why you are building such a traditional style instrument and not a Kasha style? I have never messed with the Kasha style so the answer might be obvious if I had ever heard one I guess. They sure are a different animal under the top anyway.

[Bob Webster]

Kasha. Oy. Gila Eban, a builder in Connecticut and practitioner of Kasha designs, once made the observation that it didn't really matter much how one braced a guitar. The Chladni patterns from them all looked pretty much alike.

I recently had one in for testing (built a few years ago by a local builder) and it didn't really behave any differently in where it placed notes than more conventionally built guitars. This one was nice and sweet sounding but exceedingly quiet. Turns out that it was horribly overbuilt. A 3.5mm thick spruce top and a massive array of Kasha style braces. The guitar weighed as much as one of mine in its case.

I found Kasha's approach to guitar design repugnantly arrogant. Without any real knowledge of how a guitar actually works (mainly because no one did), he decided that it should be made to behave like a broad spectrum audio speaker. Because he had formal scientific training, he thought that the problem would yield to his style of "I think, therefore it is" mentality. The problems with this are that he vastly underestimated the complexity of how the guitar works and also didn't really define any goals for his design relative to the needs of performers or audiences. Nowhere in his thinking was there any regard for how humans actually perceive plucked guitar notes and how good and bad guitars differ in their delivery of that sound.

I could go on. The point is that there are a boat load of examples of great guitars built over the last 160 years by what we would call conventional methods that we can look to for guidance.

Bob

[Bob Webster]

Yeah, that's interesting about Benedetto's practice. It's really not main stream. Most builders will avoid having the back and the top show coincident resonant frequencies because they believe that it will lead to a wolf tone at that frequency. Then, there's Jeff Elliott in the second camp, who says that he once screwed up and made them the same on a steel string he was building and it seemed not to matter at all. Go figure.

I'm in the second camp because I think it's benefecial to have a large diversity of resonant frequencies in non-top components that can also support the various notes through their interaction with the air that's made to vibrate by the top.

As for the side vibrations, everyone makes their sides a little thicker or a little thinner depending on who knows what. I was looking at the plan by Richard Brune of the 1912 Manuel Ramirez that Segovia played for so long. It has relatively thin sides, 1.8-1.9mm, but it had two little spruce patches right in the "flats" just on either side of the waist, and nowhere else. Clearly, they weren't there for structural purposes, because there are several other spots around the rim that would be equally deserving. Laminations of RW with cypress would have a different stiffness than 2.5mm of straight BRW and might show a different frequency output that just RW.

Bob

[Cliff Morris]

Well that explains it for me. I've always been a sort of empirical evidence sort of guy. If it sounds good why mess with it? The guy that drew up the plans for the Hauser says that Segovia's was very resonantly biased toward G. Apparently Segovia, or the minds that mattered back in that era, felt the G string was too weak to be useful for classical performance. I would guess that was compared to a flamenco guitar or whatever was common at that time.

[Bob Webster]

Yeah, every guitar has a main low air resonance that ends up somewhere between an F# and a G#. The body length and soundhole diameter are the main influences on that. Given that, it's important to then thickness the top and brace it in a way that will work well with that particularly air voicing. So, when you hear or read that someone is voicing the top, it means that they're adjusting the response of the top so that it drives the air resonances rather than having the air resonances drive the top.

That G string has been a notorious historical problem dating back to the gut string days. Truthfully, it takes a pretty horrible mismatch of the top and the main air resonance to get a poor G note.

Cheers,
Bob

P.S. My motto is "Data talks, bullshit walks". I think I can get away with it if it's declared a motto, can't I, Frank?

[Donald A. Fortune]

HI bob -- Not to worry about the info thing- I just thought if you had a link I could take a look see-- not that I would understand it anyway.....
As far as the tap tone thing goes, I do a tap tone many times to see what it is going to sound like,
and when I get the body done and before I put the neck to it I "sing" the scale from do to do in the sound hole, if it sounds ok to me then I put the neck on and finish it, if not then it gets put aside and I make a new body. Maby a strainge way of doing things but it works for me.. meanwhile, I'm all geared up to take on that classical guitar that I want to make..
Cheers,
Donald

[Bob Webster]

Donald, we all do strange things. If we can confine them to guitar building, then no harm, no foul.

Just a thought about "if not then it gets put aside and I make a new body". In my lurid building past there have been a few guitars that I've reworked by putting new tops on them. It's a bit of work, but it's a whole lot less work than making a whole new guitar. One of my best ever Hauser style guitars was the result of that process. It's not a bad way to go if you've only gotten creative with the top and the rest of the guitar is relatively mainstream.

Looking forward to more pics and, some day, sound clips.

Cheers,
Bob

[Donald A. Fortune]

Bob -- I don't just let the body go to waste - I work on it at a later time ..
when I tap tone a piece of wood I hold it about 1 inch in from the edge and about
one third down from the top.. then take and knock on the center like ya knock on a door but not as hard, if it goes "thud" then it doesn't get used, if it rings like the bells of St Marry's
then it gets used.. I don't have a high tec. shop so I have to use the methods that I know
to get done that I need. ( hope I'm splainin this so you can understand)
Cheers,
Donald

[Tim Mace]

one of the most resposive tappables I've heard is Narra.Someday I may try a top and back out of it.The back turned out nice on one of my mando's.Anybody else used it?

[Donald A. Fortune]

Hi Tim -- I must admit that I don't know of this material so I cant say one way or another what it would be like to use it.... sorry---
Cheers,
Donald

[Larry Schultz]

Hi Don. I've been reading the posts to your original question for a couple of weeks now, debating whether to stick in my two cents worth since you've gotten so much good advise from people with lots more experience than me (Bob Webster etc.). However, as an entirely self-taught classical maker, I think I can offer a few appropriate comments. Although it sounds like you're well on your way to finishing an outside mold I'd like to recommend you get a copy of Classical Guitar Making by John S. Bogdanovich. He has an exhaustive section on making templates, jigs, and molds that is by far the best and most comprehensive I've ever seen, although some of it seems to me like massive overkill. He also covers making laminated sides and linings and his reasoning behind using those methods of construction. I'd also like to point out that there is a very viable alternative to making and using outside molds, which is the Universal Workboard (Google "Guitar Universal Workboard" or words to that effect and you'll see what I mean). The huge advantage of the workboard/solera method of construction is that it is a relatively simple way to build a wide variety of body sizes and shapes without the expense and difficulty of building molds. I'd also like to mention that, while most classical builders still use the Spanish Foot method of connecting the neck and sides, some high-end builders like Charles Fox and Thomas Humphrey (God rest his soul) use(d) bolt-on necks ala acoustic guitars. Even Bob Webster uses a mortice/spline construction method; as Bob has pointed out, there's more than one way to skin a cat! Take a look at William Cumpiano's website for more details. Hope this hasn't muddied the waters for you too much.
Larry

[Bob Webster]

Hi, Larry. Good advice regarding the universal workboard. I made my first 15 or so guitars using my own less elegant cobbled together version of it. I would, however, advise caution in adopting some of the methods in Bodganovich's book until you get more experience with classicals. Use your own common sense in deciding to use a particular method. They all look really cool but some might not make the grade when reduced to practice. That's all I'll say on that one.

Best regards,
Bob