I have done it a few different ways over the years. If I was using a kit (such as Pearl) that has a Kick tom mount with two holes and there were no toms mounted on my kick( I usually used a rack or mounted my toms on stands), I would run it through one of the unused holes. If my kit did have toms mounted, than I would drill a small hole in the top of the bass drum, just large enough to tightly fit an XLR cable end that has a square outer edge that can be screwed into the drum with 4 small screws. I would then solder the 11/2 foot cable(inside the kick) to the mounted XLR end. Kinda like Pearl and Ddrum are doing now days with their hybrid kits. Sometimes I would just cut the end of of a mic cable, run it through a vent hole in my kick drum, than solder the end back on.