Amplification of Sound Now that we have a good understanding of how sound waves work and how they relate to the guitar, lets take a deeper look into how exactly the sound is amplified in both acoustic and electric guitars. You may think that all guitars amplify sound the same way, but this is not true. Each guitar has its own very distinct way of amplifying sound. http://www.wikihow.com/Make-an-Acoustic-Guitar-Sound-Like-an-Electric-Guitar Acoustic Guitars Acoustic guitars (like the one shown on the left in the photo above) have a very interesting way of amplifying the sound throughout the instrument. When a string is plucked at a certain frequency, it causes the bridge to also vibrate at the same frequency. As the bridge vibrates, it causes the rest of the body of the guitar to vibrate at that same frequency as well. As the body vibrates, it causes compressions and rarefactions (sound waves) to radiate outwards. This compressed air that is inside the body of the guitar is forced out through the path of least resistance (the sound hole) and thus much louder than the sound would have been if it were only the amplification of the string. http://www.guitarfriendly.net/the-parts-of-the-guitar/ Electric Guitars Electric guitars amplify the sound in a very different way than acoustic guitars do. First, let's take a look at a diagram of an electric guitar and analyze how the sound is produced step by step. http://www.guitarfriendly.net/the-parts-of-the-guitar/ Similarly to the acoustic guitar, sound is ultimately produced by the vibration of the strings at certain frequencies. Although unlike an acoustic guitar, the sound is not amplified by the vibration of the body of the guitar. In an electric guitar, as the name would suggest, the sound is produced through an electromagnetic process. When a string is plucked and begins to vibrate, the vibration is detected by the magnetic field that is produced by the pickups on the body of the guitar. These pickups consist of some sort of magnet (oftentimes either a bar magnet across all the strings, or individual magnets at each string) that produces a magnetic field. These magnets have a coil wrapped around them (usually around 7,000 times) which in turn creates the magnetic field. As the string is vibrating right above the pickup, this causes a change in the magnetic flux of the system. According to Lenz's Law, if there is a change in magnetic flux, an induced current will be produced such that the induced magnetic field opposes the change in flux. This change in the magnetic flux through the closed loop, generates a voltage (or emf) by Faraday's Law. This produced voltage sends the induced current to the "amplifier" where the sound can then by adjusted in a multitude of different ways. Once the induced current has traveled to the amplifier, it now can be distorted in any way, shape or form that the musician desires using a series of different resistors, transistors, and many other electrical circuitry. The current then vibrates the diaphragm of the speaker inside the amp at the original frequency of the string to produce the same pitch. http://www.guitaradventures.com/beginner-guitar-guide/electric