The LA of 1974 would have a Masonite ring with a 9” paper cone in a 12” basket, designed that way specifically to prevent bottoming. So either the inverted foam surround is perforated or there is another air leak somewhere…or you are overdriving them. They should handle a 125W amp easily, but you may have more. Are you boosting the low end? Don’t. People used to stack pairs to increase their output. They had impressive bass but there are limits!
Large Advents (1974) woofer pops with deep bass.
I have taken the woofer out of cabinet and swapped it to the other speaker to se if it might be a problem with capacitor but it still did the same in other cabinet. Seems to Pop on deep bass when cone is traveling out. Can I repair this or should I replace the woofer?