Need Help! Drywall has bulge where new and old wall meet

[aesmith207]

Let me start by making a long story short...Against my better judgement and the encouraged highly by the wife, my father in law and I constructed a wall in our house that would enclose a room. Studs, door, everything went up fine. The problem came when we hung the drywall. Where the new wall and the existing wall came together, it appeared that new wall slightly thicker then the existing wall creating a kind of bulge. Taking the advice of my father-in-law we starting putting joint compound up and taping the joint. It was explained to me that we would just smooth out the joint compound over a couple applications and "the bulge" would go away.

Needless to say after a couple of applications and painting "the bulge" is still there. If I lay stright edge from the new wall to the existing wall I would say there is about a 1 inch gap between the stright edge and the old wall.

My question is this, how do I fix this? I have thought of just applying more compound and trying to smooth it out, I don't really think that is going to work. I have thought of tearing down the existing drywall and putting some sort of spacer on the studs to get the extra thickness needed and then redrywalling the wall.

If you have any other ideas please let me know. I want to try to do this an easly as possible and save face with the wife and father-in-wall.

If photos would help please let me know.