Many acoustic guitar’s sound great in the tracking room but don’t sound nearly the same way when they’re recorded. In this series, based around my new book The Ultimate Guitar Tone Handbook (written with Rich Tozzoli), I’ll outline why acoustic and electric guitars, amplifiers, speaker cabinets and effects sound the way they do, and the best way to record and mix them after you’ve gotten the sound. In Part 6 of this series, we’ll look the factors that give an acoustic guitar its tone.
Also available in this series:
- Getting The Ultimate Guitar Sound – Part 1
- Getting The Ultimate Guitar Sound – Part 2
- Getting The Ultimate Guitar Sound – Part 3
- Getting The Ultimate Guitar Sound – Part 4
- Getting The Ultimate Guitar Sound – Part 5
- Getting The Ultimate Guitar Sound – Part 6
- Getting The Ultimate Guitar Sound – Part 7
It’s true that size of the instrument, types of strings used, style of picks, finger technique, soundboard, nut material and even the structure of the bracing inside all have an effect on the sound, but the woods used for the top and body probably are the most important tonal factors involved in the overall sound of a guitar.
Most acoustic guitars are primarily made of wood, so each has it’s own sonic character as a result. Since wood comes in many varieties from all over the world, even different species of the same wood will sound different when built into the body of a guitar. Let’s look at the differences.
The Guitar Back And Sides
The most important traits for the back and side wood is that it be both resonant and good at reflecting sound, which makes rosewood what many feel to be the ideal choice, particularly Brazilian rosewood (see Figure 1). It’s hard, dense and resonant, has great bass response, and flavors the tone in a pleasing way as it absorbs the vibrations from the top. The problem is that Brazilian rosewood is now extremely rare and it’s use is restricted, so other species of rosewood from Cambodia, the Amazon, and Madagascar are now used instead (see Figure 2).
While a guitar made from rosewood may be a great guitar for live gigging, it might not work as well in the studio because it may actually have too much bass response. Mahogany, on the other hand, has a very crisp, crystalline tone that works well for recording because it’s an extremely light wood that doesn’t have the low end of rosewood, which can make it fit into a mix better (see Figure 3).
Koa, from Hawaii, is another popular wood for guitar building since it has a density that falls between mahogany and rosewood, and has some of the traits of both as a result (see Figure 4). Maple has long been a traditional choice for violins and many other instruments because it’s extremely hard, but for guitars it doesn’t have the resonance of rosewood. As a result, it’s tone is sometimes considered harsh, although that can be tempered with the right combination of soundboard wood (see Figure 5). Ovankol, which is also called shedua or African teak, is sometimes used but it isn’t as dense as rosewood so it’s sound is somewhat dark.
The top wood piece of the guitar (called the soundboard) is all important because it has to be light enough to vibrate yet strong enough to withstand the pull and pressure of the strings. Spruce has the highest strength to weight ratio of any of the woods, which is why it’s the typical choice for a guitar top, although cedar, redwood, mahogany and koa have also been used. None of them are as light as spruce however, so they produce a totally different tone.
Adirondack spruce is the wood of choice because of its great tone (see Figure 6), but unfortunately it’s only found in a protected forest in New York state so it’s nearly impossible to find these days. Sitka spruce from Alaska is very strong and easily available, so it’s become a popular choice for most guitar tops (see Figure 7). Engelmann spruce has a very light weight and produces a very open sound, but because it’s not as strong the others there’s a possible longevity problem, which is also true of cedar.
Mahogany is also sometimes used for the soundboard but it has less projection and fewer overtones than spruce, which allows it to produce a punchier sound with less bass.
Common sense says that the size of the guitar has a direct impact on its overall tone, sensitivity and volume, but most players aren’t really sure about the standard sizes that are available. As you would suspect, each different standard guitar size has an affect on the tone and volume of the instrument.
Dreadnoughts, made famous by the Martin Guitar Company in 1916 and named after the legendary World War 1-era English battleships of the early 1900’s, are the most popular guitar size (see Figure 9). While Martin might’ve been the first to produce them, just about every other guitar manufacturer makes guitars in this size now as well. Occassionally a manufacturer does make a variation though, such as Gibson’s classic J-45, which is referred to as a ‘rounded shoulder’ dreadnought (see Figure 10) due to the rounded upper bout of the instrument.
Even larger than a Dreadnought is a guitar known as a Jumbo, such as the Guild F-50 (see Figure 11), Gibson J-200, Goodall Concert Jumbo, Lowden 023 series Jumbo and the Wechter 5714 Elite Jumbo.
Because of the larger body size than a dreadnought, a Jumbo projects a slightly rounder and deeper sound. Large guitars in Jumbo size are also referred to as Concert and Auditorium size guitars, but companies such as Paul Reed Smith call theirs a “Tonare Grand.” If fact, this is something that you see a lot as many manufacturers have their own names for standard guitar sizes in an effort to stand out from the crowd.
A smaller Jumbo model is called a Mini-Jumbo and is available from builders such as Seagull and Hohner (see Figure 12). These larger size instruments have more wood than a Dreadnought on the top, back and sides so they not only project a lot of volume, but also tend to have extended bass response as well.
Smaller bodied guitars are inclined to have crisper highs and a smoother midrange, but have a bit less bass than Jumbos or Dreadnoughts. Over the years there have been many models produced in different sizes and styles, each with their own distinct name. Manufacturers have called these models everything from Classic, Parlor, Salon, Steels, 00, 000, Artist, NEX, Folk, and many others.
Some guitar bodies also have cutaways on their lower bout. While this slightly reduces the amount of internal bracing and the amount of sound a guitar projects, it does allow easier access to the higher frets. As an example, Ovation’s popular Adamas series (which features a semi-parabolic shaped body made of aerospace composites) has several models with deep cutaways for easy high fret access (see Figure 13).
Although a guitar should sound great coming fresh off the line, it does improve with age. According to Dick Boak, Martin Guitar’s director of artist relations and special editions, the aging process comes in three basic stages.
- In the first three to six months, the guitar’s lacquer hardens and shrinks, which begins to open up the sound.
- Within three to five years, the finish shrinks even more, almost down to about half of it’s original thickness. The simple act of playing the guitar gets the lacquer and the wood vibrating as a single unit, which further opens up the tone.
- Over an extended period of time, the guitar expels more of the wood’s moisture weight. This makes the guitar dryer and lighter, which affects the way all the parts vibrate together, further improving the tone.
Hopefully you can now see that there’s a lot more that goes into the tone of an acoustic guitar than meets the eye. In the last part of our series on guitars, we’ll look at the various ways to mic an acoustic guitar.