I did not make any changes to the crossover. I wanted to find a replacement driver that was resonable in cost, size and overall characteristics. The XR-5 mids crosover @1.4hz up to 7khz. The HiVi has a range of 700hz-10khz. The HiVi's dimentions were the closest to the original mids. I made a templet for the opening and cut from 3/4" plywood, a patch for each speaker just smaller than the opening of the original midrange and used urethane glue to glue in the patch. The glue expands, making an excellent seal. This allowed me to use a hole saw for a very clean installation. Most of the patch was cut away with the hole saw. The HiVi's dropped right in. Before I did anything I tried to locate original replacement drivers. Next I tried to find replacement coils to rebuild the mids. I pretty much gave up on both. I have the original mids and if by chance I come across coils that fit and are the correct resistatance, they will be rebuit.