Variations of the guitar have existed for over 4000 years yet the structural design has remained virtually unchanged since Antonio Torres first developed the modern look we are used to seeing today back in 1850. This however does not mean that innovations and developments have not continued to be made in regards to the design, as one of the most important aspects of the design process of any guitar, be it acoustic or electric, is the material used to produce the body of the instrument. The selection process is one that requires due consideration as to the desired tone of the final product, with each bringing its own unique qualities.
What is the difference?
Woods in particular are famed for their ability to influence the tone of a guitar, not because they add to the sound but because they absorb it. Their differing densities and grain structure allow the materials to absorb different frequencies which alter the way in which the strings vibrate, therefore allowing each material to produce its own, individual and identifiable sound.
The sound can also be affected by whether or not you opt for a solid wood or laminate design. With solid, the entire body is made of the desired, good quality wood while with laminate, a thinner version of the good quality wood will be used to cover layers of cheaper alternatives, making it less expensive to manufacture and purchase. When strings are played on a guitar, the sound waves travel through the wood and make it vibrate but they are less able to do so with laminates, meaning the quality of sound from a solid wood body is generally considered to be better.
Spruce and cedar are considered two of the most popular, affordable materials from which to produce guitars. Spruce guitars have a clearer tone, described as Germanic in sound, while those made from cedar have a warmer tone identified as Spanish in musical origin. The reason for their popularity is that both woods mature with age, improving the quality of the sound from the instrument the more it is played.
Many different woods have been used to create commercial guitars however, ranging from Alder (lightweight and tan in colour), Ash (soft with an open grain) and Rosewood (heavy with a warm tone) to Mahogany (dense with a good sustain), Maple (durable with a distinct grain pattern) and Walnut (moderate weight with a high quality finish).
The impact of quality
Wood is graded by quality, with AAA being the best available. Generally speaking, the more expensive a guitar is, the better quality of wood is likely to have been used to manufacture it but this will not always be the case, so you should always check its grading before you commit to a purchase. If in doubt, ask the salesman as they should have detailed information on the origins of all of their instruments.
As a rough rule of thumb for all types of wood, the more uniform and neat the grain is and the less knots it contains, the better the quality and therefore the better the final instrument. The more erratic the natural structure of the wood, the more the sound waves will struggle to pass through it evenly, impacting on the sound produced.
So, the next time you are browsing through guitars, looking to make your next purchase, pay closer attention to the materials used and not just the external appearance of the instrument; it really can affect the clarity and quality of sound produced.