I dont have a shelf actually ...there is NOTHING there . Below the throttle and below the seat to the right where the "body" comes up to the dash there is nothing under there . The steering box hangs down at least 4 inches from the bottom of the dash . Im more concerned about the panel on the side . It a huge unused area , there is zero cup holders or storage on the helm or even close to the helm . As far as the speakers go , im not looking for great sound quailty honestly because i already have 8 6.5s, 2 8s and 2 10s in the boat . Would basically just be to plug the holes haha !! When the piece arrives i will take some pictures and show my idea on how to make it work !!