blown, popped speakers

How can you tell if your speaker are blown or popped? What does it sound like? I have installed some sony explod speakers, and they viberate or shake when the bass hits them.  (Not the kind viberation i want). Could these be blown? I put black tape on one of them and the viberating stop when the bass hits..

What could the problem be?

Well when you say some i assume 2. There are many things that could be wrong with the limited info you have given. If the sub was blown it would not play. If it is just damaged it could be playing just sound like junk. Where did you put the "tape"

Be a little more specific because right now there is not much we have to go on to help you. You could have a bad surround, box ,your subs could be out of phase there is no telling. Please be more specific.

Good that was one thing i thought could be wrong. Most likely it is a busted surround to the speaker. the air is escaping through the surround. You can re-glue it and it can be fine if it is on the cone side. or just leave it taped if you dont care about the looks.