To theories:
Calling: Calling to sound like prey or foe
1)Coyote howls and whimpers, wolves are very aggressive against coyotes and these may work.
2.) I have had wolves come to elk calls, deer calls and deer rattling. I'm sure other typical prey noises might work.
The other theory would be that I would not make any noise, wolves are secretive and inquisitive and might check out a bait or come through an area being undisturbed, but if noises are made that they might associate with man activities or smell, wrong time of year or etc. they might head for the hills. You might also deter from your bear hunt by calling, etc.