Sealed Enclosure

• A sealed subwoofer enclosure is a subwoofer box that contains no opening. These enclosures are often much smaller then any other enclosure, but do not produce as much low frequency bass.
  
  

Vented Enclosure

• Vented enclosures are subwoofer enclosures similar to sealed enclosures, except they contain a port near the rear of the enclosure that is tuned to a certain frequency. These enclosures provide better audio reproduction and substantial bass, but can wear out a subwoofer quicker if overdriven.
  
  

Sealed vs Vented Enclosures

• The vented enclosure is better in terms of overall quality, but sealed enclosures require less room and maintain a long speaker life.