Blown Subs?

Is there a way to tell if a sub is blown by looking at it? I don't know, I haven't ever seen or heard one... If a sub is blown, will it not work at all? (Sorry, again, never heard a blown sub, don't know if you can, lol..) Thanks.

if it is completely blown it iwll not work at all....if it is on its way it will sound like ass and will be all scrachy... to tell jsut by looking at it move the cone and listen carefully...if you hear a scrathing like noise coming from the coil it is blown or is on its way....

Awesome, thanks Fryman. I think my current subs are "On the way" lmao. Damn debiesi subs. >.<