Designed to replicate the sound and feel of our 4x12 cabinets we started with mathematical calculations to define the size and ports for matched frequency response, then used the same resonant construction of our 4x12 and fine tuned the cabinet by ear for a near perfect match. Since the early 90's these cabinets have replaced the stiff 80's style units to become the industry standard for stereo and wet-dry-wet rigs as well as home recording, after all microphones think they face a 4x12. Closed back with dual front ports, plenty of low end with nice bell like highs. Comes standard with a Celestion Vintage 30 at 16 ohm.