lmao @ this thread.
Crazycornnuts, Im not sure how you can be asking your question and be serious. You are asking why 2 subs at 600 watts would be louder than one of those subs at 300 watts. How can the notion that the dual sub setup will have twice the displacement potential escape you? Not trying to be a smart ***, but your question is so basic it borderlines on illogical.
Kid has sub in trunk with 300 watt amp. Kid adds second sub with second 300 watt amp. You are seemingly asking why the second setup would be louder.... it should be obvious, its moving twice as much air.
Arguing about 'twice as loud' is pretty irrelevant guys. Its just words and their definitions. Such as, 'of course you'll hear the difference, its twice as loud'. Its like saying 'of course you can see the difference, its twice as purple'. About the only quantifiable info you get from that statement is that it will be enough of a difference to be noticeable. What "2X" it is would be anyone's guess... or interpretation of a mathematical equation. This same arguement sprouts up here every couple weeks, dont you guys ever get tired of it? lol