Silverado Ext cab, the 99-03 body styleWhat vehicle? Single 15 should be running out of excursion unless you're tuned a bit higher and aggressively using subsonic filter. Low notes require a LOT of displacement and as you tune low to control the cone low you'll lose cone control away from (above) tuning. Are you wired to 2 ohms as well?
I'm not sure if 147.5 is even good considering I have an *** load of power on a Team AA but I imagine I can get closer to a 148 or 149 and maybe even a 150+ if I mess with the box orientation. Sub up port up would no doubt do much better
Good to hear I'm right in thinking it's normal to have it bottoming out outside of that range, one of the reasons I plan on getting a second Team AA and different box.