Acoustic Guitar

The term acoustic guitar came about after electric guitars came on the scene. Electric guitars require amplification to be heard.

photo of acoustic guitarBecause the displacement of air from the guitar string is small, something needs to be done to increase the volume. The sound board and a sound box are used. The entire body of an acoustic guitar is hollow. The vibration of the strings pass the sound through the bridge to the soundboard. That produces a much more audible sound than the strings alone.

The soundboard vibrates. The sound waves come from both the back and front faces. The box provides support for both the resonant cavity and the sound board. The chamber/box is a resonator. The sound coming from it when the air is in phase is increased by approximately 3 decibels. If the air from the strings is not in phase the air is reduced by the same amount. Some sound from an acoustic guitar is projected through the sound hole.

During this process the back of the acoustic guitar will vibrate some but less than the front. There are some acoustic guitars that do not have the sound hole, but sound resonating similar to that of a violin. All of the coupling and mixing of the sound waves and vibrations create the sound. Due to the difference in style, one acoustic guitar may vary substantially in tone from another. The complex mixture of the harmonics give the guitar its beautiful sound.

Since there is no external energy connected to the acoustic guitar, there is no amplification. The loudness of the sound is provided by the technique used in plucking the strings. The main function of the system is maximizing the intensity of sound. However due to the fact that total energy remains in a constant state, it comes at the expense of decay time.

A guitar that is not amplified will have a low volume. The strings however, would vibrate for a much longer period. This is similar to the tuning fork. The reason for this is a damped harmonic oscillator will decay exponentially. This means the life is inversely proportional to the process of damping. And example would be, the more volume is increased, the shorter the length of the sound.

Amplification

There are several different methods by which an acoustic guitar can be amplified. Either a microphone or a pickup can be used. "Piezo" pickups are mounted on the guitar under the bridge saddle. They are plugged into either an amplifier or mixer. The magnetic pickups are different. These are mounted directly within the sound hole and resemble those in electric guitars.

There is a style of guitar that was introduced by Martin that creates louder volume. It's popularity is in line with the greater volume produced in the acoustic guitar.

Acoustic Guitar Prices

Guitars are available in a wide range of prices and levels of quality. A beginner who is beginning to take acoustic guitar lessons can find a decent guitar for around $100. Professional musicians can easily spend $1,500 or more on high end, hand crafted instruments.

Types of Acoustic Guitars

The types of acoustic guitars vary as much as the people who play them. Modern and historical guitars are varied much more than their electric counterparts. Some of the more important varieties of an acoustic guitar are those with nylon strings. These are classical guitars. There are also steel stringed versions and the lap steel stringed acoustic guitar.

There are several types of guitar that use nylon or gut strings.

  • Baroque

  • Romantic

  • Renaissance

  • Flamenco

  • Classical. This is the modern design of the original with nylon strings.

Guitars that use steel strings:

  • Twelve string guitar. This is know as a steel string acoustic guitar, western guitar or country guitar.

  • Resonator

  • Battente

  • Archtop

  • Parlor

  • Lyre

  • Manouche

There are also acoustic base guitars and the Russian guitar. Along with the traditional guitars, come the novelty guitars.

Some of these include the banjo, lute, harp guitar and pikasso guitar.

Whatever the name, the mellow sound or the vibrant sound that does resonate from an acoustic guitar is unmatched by other instruments. There are many opportunities to teach yourself the basics of playing or you can hire a professional teacher for acoustic guitar lessons to carry you a bit further down the path. Whatever you prefer to do, the process of learning the fingering, the tuning, the actual playing of the guitar is something that will bring you pleasure for years to come.