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Can Guitar Finish Impact Tone and Sustain?
Are you wondering if the finish of your guitar matters for how it sounds and sustains? Have you heard conflicting opinions about whether a thin or thick coat, a glossy or matte surface, or a natural or colored tint can affect the resonance and responsiveness of the instrument? In this post, we will explore the potential influence of guitar finish on sound quality and sustain, based on scientific research and expert insights.
First, let’s clarify what we mean by guitar finish. The finish is a protective coating that covers the wood or other material used to build the guitar, as well as any decorations or inlays. The most common types of guitar finish are nitrocellulose lacquer, polyurethane, polyester, and oil/wax. Nitrocellulose lacquer was the traditional finish for most vintage and high-end guitars, but it has become less common due to environmental and health concerns, as well as some technical drawbacks. Polyurethane and polyester are more durable and resistant to scratches and heat, but they can be thicker and less breathable than nitrocellulose. Oil/wax finishes are the most natural and thin, but they also require more upkeep and may not provide as much protection against moisture and dirt.
Now, let’s examine some of the claims and evidence regarding how different guitar finishes can impact tone and sustain.
Claim 1: Thinner finish allows the wood to vibrate more freely and thus enhance resonance and sustain.
This claim is based on the theory that the more mass and stiffness a guitar top has, the harder it is for it to vibrate in response to the strings’ vibrations, and the more energy is lost as heat or damping. By minimizing the thickness and weight of the finish, some guitar makers and players believe that the wood can “breathe” better and transfer more of the string energy to the air and the body, resulting in a livelier and longer-lasting sound.
However, this claim is not universally supported by empirical data. While some studies have found a correlation between thinner finishes and better acoustic response, others have found no significant correlation or inverse results. For example, a 2016 study by Eric Meyer and Kieran Smallbone of the University of Tasmania tested the effect of four different finishes (nitrocellulose, polyurethane, oil, and no finish) on three identical guitar bodies made of Tasmanian blackwood, and measured their frequency responses using laser vibrometry and acoustic analysis. They found that the no-finish and oil-finish guitars had the lowest damping and highest resonance peaks, while the polyurethane guitar had a comparable damping and a slightly lower resonance peak, and the nitrocellulose guitar had the highest damping and lowest resonance peak. However, the differences were not large enough to be considered statistically significant, and the researchers concluded that the finish type had only a small impact on the acoustic behavior of the guitar bodies.
Another experiment conducted by the Guitarbench website in 2014 tested the sustain of two Martin D-28 guitars with different finishes (nitrocellulose and polyester), using a spectrometer and a sustainometer. They found that both guitars had similar sustain times and frequencies, despite the nitrocellulose guitar having a thinner finish and a more resonant feel under the fingers. However, the testers noted that the nitrocellulose guitar sounded subjectively better to their ears, perhaps due to the psychological effect of associating thinner finishes with vintage or high-end guitars.
Expert opinion: “While there are some differences in the way different finishes influence the performance of a guitar, the impact is generally subtle and secondary to more fundamental factors like the quality of the wood, the design of the instrument, the pickups, and the player’s technique and gear,” says Paul Reed Smith, founder and CEO of PRS Guitars. “The best finish is the one that meets the needs of the player in terms of durability, aesthetics, and feel, while not compromising the overall balance and resonance of the guitar.”
Claim 2: Glossy finish reflects more sound waves and leads to a brighter and more focused tone, while matte finish absorbs more sound waves and leads to a warmer and more diffuse tone.
This claim is based on basic physics principles of sound reflection and absorption. Glossy surfaces tend to reflect more sound waves because they are smoother and denser than matte surfaces, which scatter or absorb more sound waves. Therefore, some guitar makers and players argue that a glossy finish can make the guitar sound more “precise” or “cutting,” especially in high-frequency ranges, while a matte finish can make the guitar sound more “woody” or “mellow,” especially in mid-range and bass frequencies.
However, this claim is also not universally supported by empirical data. While there is some correlation between glossy finishes and brighter tone, and matte finishes and warmer tone, there are many other factors that can affect the perceived tonal balance of a guitar, such as the pickup configuration, the string gauge, the playing style, the acoustics of the environment, and the listener’s preferences. Moreover, the difference in sound reflection between glossy and matte finishes is relatively small compared to other surfaces in the guitar, such as the fingerboard or the bridge, which can have a greater impact on tone.
Expert opinion: “The finish can have some effect on the appearance of the guitar, but it is not a primary factor in the sound of the guitar. The pickup magnets are the most critical component affecting the tone of a solid body electric guitar, and the body shape, construction, and materials all contribute to the overall sound of the instrument,” says Michael Smith, director of engineering at Fender Musical Instruments Corporation. “The finish can affect feel and playability, as well as durability and aesthetics, but it should not be seen as a make or break element for the sound quality of the guitar.”
Claim 3: Colored finish hides or enhances the natural grain and figure of the wood and affects the visual appeal and resale value of the guitar.
This claim is based on aesthetic considerations and personal preferences. Some guitar makers and players prefer a natural or transparent finish that reveals the beauty and character of the wood used to build the guitar, while others prefer a colored or painted finish that matches their style or personality. Some guitar makers may use different types of wood for the top and the body of the guitar, and choose a finish that highlights the contrast or complementarity of the woods. Some guitar makers may also use designs or patterns on the finish to create a unique and recognizable branding or identity for their products.
The impact of the finish color on the sound of the guitar is negligible, although some guitar makers may claim that certain types of finish have a “tonal recipe” that complements particular woods or pickup configurations. However, these claims are often subjective and unverifiable, and players should evaluate the sound of the guitar based on their own ears and preferences.
Expert opinion: “The finish is a critical component of the aesthetics and marketability of the guitar, but it does not affect the fundamental sound quality or playability of the instrument,” says Jean Larrivee, founder and CEO of Larrivee Guitars. “The choice of finish should be based on the function and form of the guitar, as well as the environmental and social impact of the materials used. Sustainability and responsibility should be as important as sound and beauty for any guitar maker or player.”
Conclusion:
In conclusion, the finish of a guitar can have some impact on the sound and sustain of the instrument, but it is a relatively minor factor compared to other aspects of the design and construction. Thinner finishes may allow the wood to vibrate more freely, but the difference is usually small and not uniform across different types of wood and finish. Glossy finishes may reflect more sound waves and sound brighter, but the effect is also subtle and context-dependent. Colored finishes may enhance the visual appeal and resale value of the guitar, but they do not change the sound quality or playability of the instrument. Ultimately, the choice of finish should be based on the needs and preferences of the player, as well as the environmental and ethical considerations of the guitar industry.
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