How to amplify an acoustic guitar

There are may ways to amplify an acoustic guitar, the most frequently used are:

Piezoelectric transducer

Some crystals exhibit piezoelectric properties, that is they can generate a small electric voltage when you subject them to mechanical stress. The most common piezoelectric pickup is made of a small block of crystal or ceramic material with a metal or plastic cover, using its physical properties to capture the vibrations of the stringed instrument and transduce them into sound. Very often it is positioned under the saddle of the bridge (under-saddle pick up), an optimal place to capture most of the vibrations. It can also be placed on the soundboard with adhesive materials or screws, or under the bridge. The most common piezoelectric pickups are active, that is, are connected to a preamplifier usually running on a 9V battery that can be equipped with volume and EQ controls. This preamplifier, sometimes featuring also a digital tuner, can be hosted in an opening on a side of the guitar, or inside the soundhole.

Magnetic Pick up

Just like a pick up for the electric guitar, it is positioned on the soundhole, so that no irreversible modifications of any kind are made to the instrument. In the past, this solution did not allow to capture all the nuances of the tone of the guitar, as the soundbox of the instrument influenced marginally the global sound. Today, thanks to more sophisticated electronics and hybrid systems that can handle more pickups simultaneously, the performances of magnetic pick up reached levels that gained the appreciation of professionals in the most diverse musical genres, thanks to the definition and the power of the tone.

Using microphones to amplify the sound of the acoustic guitar is the method that offers the best performances, so it is the preferred solution by professional musicians. Of course the final results depend a great deal on the type of microphone used, on its positioning, on the skills of the sound technician and on those of the musician itself, who must be able to handle correctly the distance between the guitar and the microphone. If the guitar player must of course pay attention not to hit the microphone, he or she can use creatively the guitar-microphone distance to create dynamic, volume and feedback effects, to reach higher levels of expression.