Bought a pair of MTX Blue Thunders in 1992, 10 inch woofers, still kicking ass all these years later. Purchased a pair of JBL 8 inch woofers at the same time, 10 years ago the JBL surrounds of butyl rubber were shot, they also featured reverse phase, ie. the positives markings were actually negative, a nine volt battery test confirmed the polarity. i now prefer the rolled edge woofers over foam. I have experimented with a variety of woofers from different manufacturers over the years. Cerwin Vega rolled edge, Kicker rubber, and MTX rubber have stood the test of time. I have a pair of EV 12 inch 2 way horn speakers that were born in the late 60’s and still sound good. The vinyl wrap is peeling, but the speakers still work well. Some speakers age well.