I have a homebrew roadshow music/PA system with 421's in 815 cabinets. I drive them pretty hard with souped-up bi-amped Hafler D-500's. They are definitely tougher than 515's, but can really handle the work. Never lost a voice coil, but I have shattered one cone. Maybe it failed from age/brittle. Has made good money for me for over 12 years now with very little maintenance.

The top end is MR64 horns and 291H drivers.

Comments run from 'turn it down!' (ignored), to 'That stuff sounds awesome'....

DG

ps...A tip: never point the bins at each other...one good thump from a kick drum and the opposite HF horn driver diaphragm will shatter...the horn works both ways (think funnel).