Speakers can deteriorate with age. The flexible foam surround that allows the speaker to oscillate (and generate sound) can start to disintegrate.
The speaker foam, or rubber surround holding the cone to the speaker frame can deteriorate with age and become perished. If this happens, the speaker or speakers will not work in the way they were originally designed. If you have another speaker of the same age and cone type, this is also probably about to fail. It’s likely both will need to be refoamed. The repair can prolong the speaker’s life. It will save you buying a new pair, plus you’re doing your bit to save the speaker from landfill.
This video shows you how to repair and replace the foam surround, and get your speaks back to sounding as good as new…
Can be found on this page: How to Repair Your Speaker – Replace the Foam Surround (Refoaming): (Opens in a new window / tab)