Thoughts About the Design of the Spanish Guitar


Contents by Juan F. Fernandez-M. (about me)


Please write me if you have any comments to improve these pages.

These pages explore the rich features of the Spanish guitar design by analyzing the essential principles implemented on the soundboards of famous guitar builders using finite Element analysis (FEA).

I base my discussion mostly on the plans available from the Guild of American Luthiers, Roy Courtnall and Allied Lutherie, but I also use designs deduced from published photographs in guitar books and magazines, and from my own observations.

I am currently adding some designs based on the sketches found in the book "A collection of Fine Spanish guitars: from Torres to the present" 2nd, edition, by Sheldon Urlik (Sunny Knoll Publishing), that is worth every penny.

The models presented here have been "standardized" to allow for comparisons, so I am not claiming that I am reproducing exactly the available plans. In addition, for most of the models, only sketches are available, so I had to make several assumptions that are explained in each case. The standardization involves using 5x5 mm struts (unless the model really needs different strut heights) and I make all them fit onto the same geometry.

My goal here is not to simulate specifically the soundboard of a particular guitar, but to rather understand the effects of different strutting design geometries on soundboard with the same stiffness, something that is impossible to do in the real world. I focus particularly on the frequency response of the fundamental mode, as this is a measure of the relative stiffness of the different models.

The list of guitars is not exhaustive.  I believe I have included the essential instruments from the recent history of the guitar, from Torres to Fleta, with various entries for Santos Hernandez as I consider him a great innovator of the classical and the flamenco guitar.

I am posting some  photos of my current project of building a Santos Hernandez-style guitar here.


A note on tropical hardwoods can be found here. Please build responsibly!


I. The Basics


II. Vibration modes of main designs


  1. Antonio de Torres 1888 design

  2. Manuel Ramirez/Santos Hernandez 1912 design

  3. Enrique Garcia 1922, 8 fan design

  4. Santos Hernandez 1923, slanted bar Classical design

  5. Santos Hernandez 1930, Classical design

  6. Santos Hernandez 1934, flamenco design

  7. Hermann Hauser I 1937, ex Segovia design

  8. Marcelo Barbero 1951, Flamenco design

  9. Ignacio Fleta 1960's design

  10. New! José Luis Romanillos - Bream design



    III. Other models


    This section includes models that are difficult to assign to a specific marker or to a specific date, or if I have doubts of its precision, but that are interesting enough to take a look at.




    IV. Summary of simulations



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Last updated: November 3, 2016