M.B.
Some cats prefer a horizontal scratching area..... one of my cats absolutely LOVES the corrugated cardboard scratchers.. I would get the one that is about 8-10" wide (instead of the 4" wide one) to give them plenty of movement area.
Sprinkle the new scratcher with catnip to encourage him to go there... and go over and scratch it with your fingernails to get him curious about the sound..... then PRAISE and pet when the do use that scratcher.