dbx CX-3-mkII is a control amplifier that can be used in two ways: as an audio preamplifier in a hi-fi stereo system or as a control center for a video system. It features various input and output connectors, making it compatible with various audio and video components. The CX-3-mkII also boasts unique features like three types of surround processing, which can enhance the audio experience for movies and music. Additionally, it has tone controls for bass, mid, and treble, allowing you to customize the sound to your liking.