Speaker Surround Question

Do all speakers have surrounds? My vintage Jensens have 12 inch drivers with no visible surround. The cone looks like paper all the way to the edge. What does a surround, such as foam, do for a speaker? (It must have some function other than rotting! :confused: I've lost three sets of bookshelf speakers over the years due to foam rot. :mad:)

Bobby Dipole
 

nac134

Member
2008-09-04 1:47 pm
B and W also has made many kevlar midrange drivers with no surrounds. The purpose of the surround is to allow the cone to move back and forth without the cone having to flex. Thats why subwoofers often have big surrounds - the cone has to be free to move a large distance back and forth.
When a driver has no surround, it is the cone itself that it flexing when it moves. This of course only works if the cone does not have to move very far.