My towels smell.HELP?

Okay, i figured it was the laundry det. so i changed it. no change.Everytime i wash towels they smell great coming out of the washer but as soon as i take them out of the dryer they smell kinda moldy. Well we ended up just buying some new w/d (front loaders) and they still do the same thing. And keep in mind its only the towels that smell.Even my new ones. What can i do?