THIS PAGE IS A DRAFT / to be completed !

This article was originally published in American Lutherie #124 / Winter 2015
See www.luth.org.

The Leonardo Guitar Research Project (LGRP)

How the story started
  Could it be possible to make great sounding guitars out of sustainable local non-tropical woods?  This challenging
question started a heated debate between teachers and students from three European guitar making schools at a
Belgian guitar show a few years ago. Of course, we all knew that tropical woods make the best guitars, and that these
woods were getting scarce and more expensive, but was there an alternative? At the end of the evening, after robustly
discussing the pro’s and con’s of tropical versus non-tropical woods, we unanimously agreed that we could only
answer the question by actually doing research with a selection of alternative non-tropical woods in comparison to
tropical wood. But, moving from an hypothetical discussion to a solid research project presented a number of
challenges: we needed funding, we needed capacity to make sufficient guitars for meaningful comparisons and we
 wanted a broad research team including independent professional luthiers.

A need to find alternatives to tropical woods
  After exchanging our different points of view it became clear that we would need to consider the wider context for
using tropical or non-tropical woods, including the technical, economic and ecological perspectives of their use.
Many of the finest acoustic guitars used today employ exotic tropical woods for the backs, sides, necks, bridges and
fretboards. These fine woods are much sought after for their tonal quality and appearance. But the increasing demand
for exotic tropical woods on global markets has led to the destructive and often illegal logging of the rainforests where
these woods are found, with severe consequences for the climate, eco-systems and indigenous people. Still, exotic
tropical tonewoods remain the bedrock of high-end classical and steel string acoustic guitars. The reason for this is
that alternative woods just do not appeal to traditionalists. Tonal quality is inextricably linked in musicians’ heads with
old-growth exotic wood.
  Today, many of the exotic tropical woods are protected and their trade restricted under the Convention of
International Trade in Endangered Species (CITES). For the luthier it means that these woods, which have been
traditionally used in guitar making, are becoming ever more scarce and ever more expensive. For those tropical
woods still available, the guitar maker needs to exercise care to ensure that they are from a legitimate source as,
despite certification processes such as that of the Forest Stewardship Council (FSC), much of the available tropical
wood is illegally harvested.
  From the point of view of instrument makers, the increasing regulatory environment and pressure from environmental
action groups will continue to decrease the availability of tropical woods, with consequent upward pressure on prices
to meet demand. Criminal organizations will continue to attempt to meet demand through illegal logging, and luthiers
will need to be vigilant to ensure that their tonewood supplies originate from reliable, certified sources. Against this
background it is becoming increasingly important to search for and develop alternatives for instrument making that
allow the crafting of high quality guitars in an economically viable and ecologically sustainable way.

Making the project a reality
  The Leonardo Guitar Research Project team came together for the first time in the summer of 2012 to kick-off the
project. Today, the LGR-Project is a non-profit partnership amongst 3 guitar making schools (the Centre for Musical
instrument Building, Belgium; Ikata Arts and Craft School, Finland; Newark College, UK) and 4 independent European
luthiers, (Lorenzo Frignani, Italy; Thomas Holt, Spain; Chris Larkin, Ireland; Remi Petiteau, France). By using the
schools best students, under the close guidance of the teachers and expert luthiers, we created capacity to make a
large number of guitars for comparison. As for funding the project has been financed since start up through the
European Union’s Cross-country training programs.

What we want to achieve
  First of all the Leonardo Guitar Research Project wants to study, demonstrate and communicate the possibilities of
building acoustic and classical guitars from non-tropical woods. Secondly we aim to develop a knowledge platform
concerning the use of alternative non-tropical wood species in guitar making. Additionally, the research may provide
some ecological benefits; If the research can show that locally grown sustainable non-tropical woods can be used as
viable alternatives to tropical woods for guitar making, then this could result in a situation where luthiers begin to seek
out these alternative woods; and this could create a new market for wood suppliers. Moreover this could begin, in a
small way, to help soften demand for tropical woods. Clearly any move to local sustainable non-tropical woods has
important environment benefits, through reducing unsustainable rainforest deforestation and by reducing carbon
emissions via shorter transportation routes. A broad-scale use of non-tropical alternative woods in guitar making will
not, on its own, have a significant environmental impact as only a very small proportion of the worldwide harvested
tropical woods are used for the crafting of guitars. The majority is used for furniture, paper production and for building
materials (floors, doors, window frames, terraces etc). However, if guitar makers and musicians choose for
sustainability, they could have a big impact on the whole instrument making industry. In turn this may help influence
society to switch to alternative sustainable solutions for the wider range of wood products.

The research
The schools so far have made a large number of guitars using a range of non-tropical woods not commonly used in guitar building including ash, birch, oak, chestnut, plane, walnut and many others. Tropical counterparts for each model were also made, using Indian rosewood for backs and sides, mahogany and cedar for necks, ebony and
rosewood for fretboards and bridges. The classical guitars used for the tests (10 non-tropical and 5 tropical, see fig. left) were based on a Torres model. All these guitars used European spruce of the same quality for soundboards and bracings. The guitars were produced by advanced students under intense supervision of the teachers to ensure all aspects of the build process were controlled, including neck and fretboard shapes and the final setup.
The Figure left is showing the woods used for backs and sides: Alder, Oak, Walnut, Beech, Ash, Birch, Chestnut, Plane, Boxwood, Robinia, and 5 times Indian rozewood.

Evaluation of the guitars
We set out to determine if guitars made from non-tropical woods could be distinguished for sound quality from their tropical wood counterparts. The project guitars underwent a rigorous testing program consisting of various blind and non-blind comparative tests using professional guitarists and expert listeners in room conditions, and with public audiences in concert hall conditions. The
testing methodology consisted of: 
a) Blind and non-blind pair testing, where guitarists played (and expert listeners listened to) a series of matched guitars (one non-tropical and one tropical) and provided their sound preference.
b) Blind group testing, where guitarists were asked to choose their preferred guitar from a group of 5 (tropical and  non-tropical). This test method was designed to simulate the real life procedure of a guitarist choosing a guitar to purchase from a group of guitars in a shop, but only by ear and not by any visual criteria or knowledge of the woods used.
c) Blind and non-blind evaluation of guitar pairs with public audiences in guitar festivals in Belgium and Finland.
The results and conclusions
The amount of data generated by the testing program was large, the guitarist and audience testing alone has
generated more than 4500 individual data comparisons. We found a very high degree of consistency in the results
across all the testing methods.
a) Averaging the results for sound preferences across the guitarist and expert listener in the pair testing showed that,  under blind test conditions, the preferences were equally distributed (50:50) across tropical (T) and non-tropical (NT) guitars. However, under non-blind conditions, the tropical guitars are strongly preferred over the
non-tropical guitars (75:25). See Figure 3 a.
b) For the blind group testing, the average result across the guitarists was again equal with a result of 51:49.
The consistency of the results and the quality of the verbal feedback from the guitarists on this group test suggests that this is our most sensitive and reliable test method and we will further refine this methodology in our future research. See Figure 3 b
c) The audience testing from Belgium (Cordefactum Guitar Festival) and Finland (Tampere Guitar Festival) confirmed
the above findings. Under blind test conditions the audience preference was 49:51 in Belgium and 51:49 in Finland
(again averaging an equal 50:50). Again, when tested under non-blind conditions, with the audience seeing the guitars
and being informed of the woods used, the sound preference shifts to favor the tropical guitars (55:45), See Figure 3 c
The results from all the blind testings taken together, be they pair testing and group testing, showed that the guitarists,
listeners and audiences had an equal sound preference for the tropical and non-tropical wood guitars.
Figure 2: A blindfolded guitarist testing one of the project guitar.
(details of the methodology and the test results can be found on www.leonardo-guitar-research.com)
So non-tropical woods can be a viable alternative, but…
The main conclusion is that blind testing shows non-tropical woods can be used to make guitars equal in sound
acceptance to those made with tropical woods. This result is consistently true across the pair, group and public
audience blind testing.
However, under non-blind conditions, the sound preference shifts strongly in favor of the tropical wood guitars. This
appears to be due to the visual nature of these tests where aesthetics (e.g. a preference for darker woods for backs
and sides; black fretboards) and/or pre-conceptions about tonewoods (such as; the best guitars are made with tropical
woods) appear to exert considerable influence on sound perception.

And finally…
Thanks to additional funding from the European Union we are able to continue the project till end 2017. During this
second phase of the program we shall be building more guitars and refining our testing procedures to deepen the
research, and we want to understand more of the role played by aesthetics/tonewood prejudices and their influence
 on sound perception.
Visit www.leonardo-guitar-resaerch.com if you want to stay updated, receive the LGRP-Newsletter or if you want to
contribute to the research as a guitar luthier.

Authors: Brian Garston and Jacky Walraet
The Leonardo Guitar Research Project, Europe.

Figure 3 (a,b,c): Results of Blind and Non Blind Testing amongst guitarists, listeners and audiences .
NT = preference for the Non-Tropical guitars, T= preference for the Tropical guitars
50 %
50 %
25 %
75 %
 Average Blind Pair Testing,/
guitarists and listeners
Average Non-Blind Pair Testing /
guitarists and listeners
NT 51 % T 49 %
 Average Group Testing, Blind / guitarists
50 %
50 %
45 %
55 %
 Average Blind Pair Testing /
Average Non-Blind Pair Testing /
Figure 4, The non-tropical LGRP guitars on display
at the Cordefactum Guitar Festival, Belgium.