Contact (sounding board and under-saddle) elements
Contact elements are immediately put on the guitar and they receives signal and then convert the vibrations of the instrument, which can be amplified as sound. Some people suggest contacting elements such as piezo elements. Generally speaking, there are two different places where an element can be mounted on the guitar: on the soundboard, or under the seat.
The soundboard is simply the top of the guitar. The top of the guitar vibrates and produces sound as you play and that makes it a good place to put your contact element. Soundboard Elements resemble small slices, not much larger than a coin of 50 cents, and you usually put two or three on the soundboard to capture the sound of the instrument. For a less permanent installation of these elements, it can also be placed on the outside of the top sheet. For a more permanent installation, place them in the guitar at the bottom of the top.
Under-saddle elements look like a small wire rod made of a piezoelectric material, and they are, as the name suggests, located under the saddle of your best beginner guitar. The saddle is a piece of plastic (or leg) over which the strings are located at the point where the bridge is attached to the upper blade. Under-saddle elements are probably the most popular inverters used by performing artists. They are almost immune to feedback, as soundhole elements, but give much clearer and more precise the sound of the instrument, almost as well as a microphone. Compared with other elements, under-saddle elements are probably the hardest to install, because you may need to drill a hole for the wire and you have to make the saddle slot wider or deeper.
Review of elements
Now that you know a bit more about the different types of elements, it is good to have a few, or several, to try to see how they are doing it on your guitar. Some elements may have the upper registers are popping out, others may have more coming out of mid-range and others can make the loudest bass sound.
As a rule of thumb, an expensive element does not necessarily lead to “better”. So try to, listen to and read reviews about various elements incredibly important.
Where you basically have to look at when it comes to sound matters is how well the elements reproduce the natural sound of your guitar; that means that the element must have a fairly balanced EQ display, or sliders, and buttons that you can get a balanced EQ display. The best way to see the EQ display is the element directly to a PA system to connect and not on an acoustic amplifier, because it will add its own texture. A direct connection gives a very close approximation of the natural sound. If you can not arrange to have a decent tone comes out, then chances are that you should not have that element.