yea i had one 12 l7 in a sealed 2cuft and it was ok but not super loud and put 850rms to it and i wasnt happy, hooked up another a dual 12" box pushed them with bout 500rms and it was better than one, then went to aeroport in a 5.2cuft net tuned to 34hz with only 400rms per sub and it was a major difference now i am waiting on my zx1500
but for only 750rms for sealed is not going to be superloud so i would suggest a 15" for cone area