Sounds like your stand hunting. I would change your tactic if you have seen nothing and go to spot and stock. Use it as a locating call and hit the lost cow while walking throught he woods intill you get a response.
Hunt the mornings trying to find the feeding areas.You want and try to intercept them between feeding and bedding area. Stay out of the bedding area.It's not an easy deal to hunt Elk that is why preseason scouting is so important.
I didn't have a chance to scout myself and have been hunting 10 days straight with no success. The rut is nearing in my area anyway and they might become a bit more vocal to help out in locating.
Finding them believe it or not is the easy part, getting a clean shot at a mature bull with a bunch of cows eyes looking around is another story.
Good luck