Never blew JL's subs. As far as the gauge of wiring, 4 then went to 1 amp still melted them both. Fosgate amps are very power hungry, i just think that the newer ones are not as up to par as most of the older series fosgates. They look nice though!!
As far as cranking new speakers past distortion, NO, moderate play even set the gain to a 1/4 turn and the bass and sub level on the deck below 2db's. I think the second one that went was just a freak spike though.
