LGRP in American Lutherie

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 a 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. 1) 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.

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, see Fig. 2.

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, see Fig.3

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 Fig. 4a.

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 Fig. 4b.

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 Fig. 4c.

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.

(details of the methodology and the test results can be found via this link)

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-research.com and receive the LGRP-Newsletter if you want to stay updated or if you want to contribute to the research as a guitar luthier.

Autors: Brian Garston and Jacky Walraet

The Leonardo Guitar Research Project, Europe.

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Thanks to Tim Olson and R.M. Mottola for helping to create this article in the American Lutherie Journal.

Fig. 1/ The 15 guitars used for the tests