if ur choosing to purchase subs or amps that were previously hookd up, can't be tested....what signs can tell u the speaker/amp has been abused?

 

MORE INFO NEEDED
where and how i.e ebay ,in a home ,in a shop, or on the web

 

when u have em in ur hand and lookin at em

 

not even then, you cant tell shiit until you hook it up.

 

very difficult. Sometimes you can see damaged parts, burnt tinsel leads, fresh glue from a recone or surround repairs, and mechanical noises when the cone is pushed can give indications of damged coils, mis-aligned suspension or poor repair, but not always.

 

Easy stuff to do would be

Open up the amp and see if anything looks burned.

If its a sub, just move the cone up and down and see how stiff it is. If it is very loose, odds are you shouldn't buy it.

For all drivers, look for tears in the surround, If when you move the cone you can hear rubbing then that's no good was well.

 

if you can move the sub cone without hearing grinding, that is always a good thing.
if it doesnt move smoothly, dont buy it.