I have picked the MAD1259 Polypropylene subwoofer for my project.
This well known woofer had shown nice performances in many subwoofer projects around the world. This is an advanced version of the old NHT 1259 and was mafe by Foster. It was especially designd for sealed enclosure subwoofer boxes and suits music high end critical listening apllicaions.
* The MAD1259 is not availble right now but you can pick a very good alternative as the Dayton RSS315HF-4 12 and it will do a great job just pay attention to its cuts dimentions.
The silicon diy ring for sealing.
The woofer with the dried silicon is glued with a fresh silicon to the box.
