100w 6.5 Inch High-power Subwoofer Speaker Home Passive Subwoofer Audio Diy Home Theater Hifi Fever Large Magnetic Steel Speaker - Speakers - AliExpress
I built a subwoofer for my home theater! - YouTube
How to Design Your Own DIY Subwoofer - TurboFuture
DIY HiVi SP10 Subwoofers - DIY Audio Projects Photo Gallery