It's the source.
Believe it or not. A lot of dubstep songs have that clicking in the back. Most especially if they are not high quality recordings.
Almost always it is timed with the beat of the song.
I noticed them when as I got more detailed/revealing iems and headphones.
So. maybe it's just testament that despite the hella bass and "muted" mids and highs, the XB500s are better than your titans?
Yes I like the xb500s a lot better than the titans so far. The only think I don't like besides the clicking is noise leakage. But honestly, the bass level is just perfect for me. I'm going to try some higher quality recordings of the same tracks I had problems with and see if that solves my problem