The enclosure design and model frequency response are shown below.
- 10" 4 ohm subwoofer
- O-Audio 500 Watt plate amplifier
- Freq Response: 25Hz up to chosen x-over point.
- Overall Dimension: 21"x 12.75"x 20"
For more details on how to make it please read more http://diyaudioprojects.com/Speakers/HiVi-DIY-Subwoofer/