The Meridian Preamp features a unique mid frequency control system that lets you dial-in a studio quality acoustic guitar tone while holding feedback at bay. The Meridian microphone has one serious advantage over an internal guitar mic. It is NOT inside the guitar. The true guitar sound logically happens outside the guitar body. Inside there are, aside from an excessive amount of bass frequencies, various sound reflections that do not represent the true tone of your instrument. An external mic captures the guitar sound as YOU hear it.