Resonance. When the frequency of an externally applied periodic force on a body is equal to its natural frequency, the body rapidly begins to vibrate with an increased amplitude. This phenomenon is known as resonance. Jeon Ailisue. Music, her first love. Piano, the medium through which she expresses her love. Choi Soobin. The voice she fell in love when she first heard it. Being in love with that voice came just as naturally to her like being in love with music. And this is their story.All Rights Reserved