2.1 System question ???

[Dxvideo]

Hi all,

Last YEAR i started to make a 2.1 system with 3 x TDA1514A. Yea somebodys warned me in this forum that "do not use TDA15A" but i tried. I worked hard and finished. And at the moment that three amplifiers work well. No noise no hum no mrr but good sound performance. Everything looks like wonderfull.... Until SUBWOOFER;

- I have a very good 16cm (6.5") Westra driver and i want to use it for my subwoofer,
- When i use it with a 24dB LPF + TDA1514A (in 4 ohm 50W) + 25 liter ported box, yes i can hear deep bass but its not like my logitech x230 (it has only 5" subwoofer, appx 7 liter ported box and just 20W RMS) logitech has a deeper bass and very soft feel.
- When i use it with the Linkwtiz transform circuit + same configuration i hear a lot of noise, and the driver moves like crazy but still no deeper and soft bass...

How can i design a subwoofer equaliser to work it like a cheap China made 5" subwoofer?