Wiring 3 Subs at 1ohm

I have a Clif Designs 1500 watt amp that is capable of running at one ohm, which is how I used to have it ran on my previous system. I just recently installed one more 12" sub and obviously installed a triple box as well. My problem now is that I don't think I have it running at 1ohm and it seems like I should definetly be getting more bass than I am. Do you think that the new sealed triple enclosure is just making it sound quieter compared to the vented box that I used to have in the trunk, or does it just sound like it is not running at one ohm anymore? By the way, I had my gain on the amp at just over half before, and now it's over 3/4 and it seems that the old setup was pretty comparable in bass.

This image is what I used to wire everything up. The subs I am running are Audiopipe TXX-BC12's. Any input would be greatly appreciated.

3 subs / Dual Voice Coil - 2 ohms x 2

The main prob I am seeing is that Those subs are Rated at 700 Watts RMS and with this setup is that even if the Cliff Amp is putting out the whole 1500 watts at one ohm ( which I doubt it is) you are still underpowering those subs.....

The subs are only getting about 500 watts apiece if the amp is running at max output and getting a 14 volt feed...

Also the fact that you did switch from a ported enclosure to a sealed one is also contributing to the sound you are getting now...

Thats my dime...