Presented herein are intra-operative techniques for setting the angular insertion depth of a stimulating assembly during implantation into a recipient's cochlea. In certain embodiments, the angular insertion depth is monitored in real-time and advancement of the stimulating assembly is terminated when a selected angular insertion depth is achieved. In further embodiments, a linear insertion depth that corresponds to a selected angular insertion depth is intra-operatively calculated and advancement of the stimulating assembly is terminated when the calculated linear insertion depth is achieved.