What's the sound difference between blown out speakers and needing new foam?

Question

I have a pair of beat up JBL MRV308's, however all the foam on the outside of each speaker is missing, and I suspect some of the speakers may be blown out (especially the top, higher-frequency portions). I'm not particularly knowledgable on speakers however I want the experience of fixing one.

How do I tell if a speaker is blown out or if it just needs new foam around the cone? Or if the foam doesn't impact sound quality at all please let me know as well.

The speakers currently sound much much quieter then you'd expect, and at high volume there is crackling (although I think it's mostly just from the higher frequency portion of the speaker)

Again I'm mostly looking for something to fix up, although I want to know if this is a lost cause.

Answer 1

Throw those in the bin, unless you want to replace all the drivers.

Anything allowed to get into that state isn't even worth opening to see what may be salvageable.

The cones are free-floating on their own magnets - so the coils are destroyed.

They've been wet, so the cones are destroyed.