Help! Why does my hair NEVER smell good?!?

I seriously am at the end of my rope with this. Minutes after getting out of the shower, my hair takes on this musty smell like old books or a dusty attic... it's horrible! I've tried more shampoo, less shampoo, no shampoo, all different shampoos, washing more, washing less, various products and drying/styling methods... always the same icky smell. Have you ever experienced anything like this or do you know anything that can be done about it? I'm so self-conscious.