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, and from my own observations. I added 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).

My goal here is to understand the effects of different strutting design geometries on the same soundboard, 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 key measure of each model. The models presented here have been "standardized" to allow for comparisons. The standardization involves using 5x5 mm struts that I fit onto the same plantilla to avoid confounding effects of different guitar sizes.

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.

Note: the broken image issue seems to be solved, please let me know if there are some that don't work.

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

Look also at the Leonardo Guitar Research project for building guitars only with temperate woods.

Featured luthiers

Stanley guitars, Australia, if you are looking for the perfect cross-over guitar

Tobias Braun, fine replicas of Santos Hernandez guitars

John Ray in Granada, fine replicas of Torres and Santos guitars

Simon Ambridge, fine replicas of Torres guitars

Richard E. Bruné, needs no presentation!


Rudolf Fuchs' quarter sawn-split German spruce tops of the highest quality

Bois de Lutherie, France: excellent quality maple and other temperate woods

I. The Basics

How can we use finite element analysis to optimize the design of guitars?

Basic bibliographic references: Please read these first!

How to draw a simple classical guitar profile useful for simulations?

Wood properties used in the simulations

Example: The Vibration of a guitar soundboard without reinforcing

Updated! Finite element analysis for the design of the solera

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. José Luis Romanillos - Bream design

  11. 80's Kohno style design

III. Summary of simulations

Summary of results

What advantages are produced by asymmetric designs?

Last updated: August 27, 2017