While there are many types of acoustic guitars available, they mostly break into two groups. Nylon String acoustic guitars are mostly used for classical music, and Steel String acoustic guitars are popular for rock, blues, jazz and other types of music. Click for information on how to Buy Acoustic guitar (also called the AXE since the shape of electric guitars are somewhat axe-y) , or for Electric Guitar Types. The sound made by nylon string acoustic guitars is softer, and nylon strings are easier on fingers - which makes them the ideal choice for fingerpicking styles of music (such as classical). Steel string acoustic guitars have a more forceful sound, and while steel strings can also be fingerpicked, they are more painful to use for this fingerstyle playing. One thing to note is you should NEVER put steel strings on a guitar built for nylon strings - steel strings have much higher tension and it will cause the neck of the guitar (which was designed for nylon strings with less tension) to bow.

Acoustic guitars are almost always made of wood, and the choice of wood used in making the guitar give it a distinctive tone. Cheaper acoustic guitars are made from cheap plywood (or laminate), while expensive acoustic guitars are made from premium solid wood. Economical hybrids have some parts made of solid wood, and some from cheaper laminates. The different parts of an acoustic guitar (normally having six strings) that contribute to its sound are the back, sides, top, neck and fingerboard. Most musicians agree that the top wood of an acoustic guitar (the part with the soundhole cut in it) is by far the most important factor in the sound of the acoustic guitar. Spruce is a very popular top, but since white spruce trees are now hard to find in the US, Sitka Spruce is often used. Many cheaper guitars also use Spruce for the top while saving costs by using laminates for the rest of the construction.

The back and sides also play an important role in the sound of an acoustic guitar. Click for information on Acoustic Guitar Parts. Expensive acoustic guitars have premium solid wood for the back and sides, while cheaper guitars may have all or some laminate parts. The shape and size of the guitar body also is an important factor in its sound, and as the back and sides essentially define the body of the acoustic guitar - the combination of size, shape and wood used makes a dramatic impact on the quality of sound. The neck provides tension to the strings, and while a steel bar inside the neck takes most of the stress, the wood used for the neck also affects the sound of the guitar. The fretboard that runs under the strings (and has the frets embedded in it) also contributes to the sound that guitar can make. All acoustic guitars have to be "broken in", the wood has to be seasoned with age to produce its best sound. The guitar top is what provides the resonance, and it tends to take on the characteristics of the music style that is played on that guitar. If your music style is with heavy bass, that guitar will tend to develop a good bass "boom" over time. If you tend to play more treble such as blues notes, that , you know, guitar will develop a well defined trebly "twang" as it ages. Note that an acoustic guitar can take 5 to 10 years to break in. When you buy a new acoustic guitar, always choose one that sounds good - as it ages, it will sound even better. On the other hand, a lousy sounding acoustic guitar will only sound less bad over time. One trick that guitarists use, is to lean the new acoustic guitar against a stereo (or boom box) that is continously playing the style of music they intend to play with that guitar. The theory goes that the vibrations from the speakers will "break in" the guitar faster. Wether this is true or not is not known, but it is a popular urban legend among guitarists.

Acoustic guitars come in different sizes and scales. The Dreadnaught is the largest and loudest acoustic guitar (some call it a GAT) size (also called the "D" size). The full size acoustic guitar is the normal size. Some manufacturers have an Orchestra Model (OM) size which is a little smaller than full size, other guitar makers use the term Concert Size. The 00 and 000 sizes are smaller and less thicker, which is good for smaller sized guitarists. The Travelling size acoustic guitar is very compact and is meant for portability, although the sound quality leaves a lot to be desired. For small children around 5 years of age there is the 1/2 (half) scale guitar, which is smaller and shorter which makes it suitable for kids. The 3/4 (three quarter) scale guitar is for larger and older kids, which is a little smaller than a 000 size guitar so they can hold it comfortably.

There are variations in the length of the neck scale as well, with shorter scale acoustic guitars having the frets closer together. The guitar neck comes in two types; the "C" neck (rounded back shaped like a C), and the "V" neck (sharper back shaped like <). The neck shape does not affect the sound of the guitar, it is a matter of choice and comfort based on the size of your hands. The width of the fingerboard affects the spacing between the six strings, and should also be considered for comfort based on your hand size and finger length. Fingerboards can vary from 1.5 inches to 2 inches, the wider fingerboards make it easier for fingerstyle playing - as the strings are further apart, making it easier to get your fingers under the string for plucking. Narrower fingerboards are easier to play with a pick, as there is less effort required to strum the strings which are closer together.

Most acoustic guitars have only 12 or 14 playable frets. The shape of the body prevents easy access to the rest of the neck. To get around this limitation, some acoustic guitars have a "Cutaway" where the neck meets the lower body. This allows easier access to the higher frets, but it does affect the amound and quality of sound as the shape of the guitar has changed internally. Since the cutaway allows access to more frets, some of these acoustic cutaway guitars have more frets as well. This affects the playability of the guitar, since its frets are closer together to accomodate the extra frets. Some newer acoustic and acoustic-electric guitars (such as Ovation guitars) have plastic backs with odd bulges. This is supposed to increase the volume and retain the sound quality, but its a matter of opinion and choice. Acoustic-electric guitars have a built in "pickup" microphone, so you can either play it acoustically or plug it into an amplifier (amp) for more volume. There are also add-on acoustic pickups that can be easily added to any acoustic guitar, some are mounted inside the body while others clip onto the soundhole without any installation.