Thread: how do you know if your subwoofers are shitty?

i have 2 of these http://www.cardiscountstereos.com/catalog%20page.asp?Product+%23=HFI12D4 subwoofers and i built my own box but they dont seem right the make like a weird sound when the bass gets loud and dont really hit but when they arent up loud they sound good with the bass while with my other subs they were always good??

you know yoru subs are shitty when they retail for 19 new and if you dont know anything about building a box maybe you shouldnt make your own if you just make the port any size that looks right you will never get anywhere if you want something that sounds good invest in a better sub and have a professional build you a box