I recently got the astro mixamp and some AD700's. I used the zalman clip on mic but my friends constantly told me they could never hear me so I decided I need a boom mic. I had heard about fragtality's velcro mod but I wanted something more elegant so I decided to actually install a jack in the headphones for a removable mic. I ran the mic cable with the stock AD700 cable through braided sleeving and it splits off into the 3.5mm audio and mic terminations. I used Neutrik 231-BG connectors for the end terminations and the female jack in the headphones. The mic was around $.40 on Amazon and works perfectly. There is no point of this without pics so here they are:
I hope you like it!